Microbiowiki - Recently Updated Pages

The Microbiowiki Homepage

flattail — Tue, 15 Sep 2009 12:57:48 CDT

The Microbiowiki is an educational site for college-level introductory microbiology students. It is open for anyone to join and edit. If you are a teacher or class who wants to use this extensively please talk to Kevin about how it could best be modified for your use. Welcome, and have fun!

First Introductions		How Microbes Function
1. What is a Wiki and What do I do? 2. What is Life? What is a Microbe? 3. How are Microbes Grown? 4. Historical Tour of Microbiology		1. Microbial Nutrition and Growth 2. Microbial Metabolism 3. Microbial Genetics
Getting Sick, Getting Better		Killing Microbes
1. How to Get a Communicable Disease 2. Your General Defenses 3. Your Specific Defenses 4. Diagnosing Infections		1. Physical and Chemical Control 2. Controlling Microbes with Drugs
Diverse Life Forms		Bad Bugs!
1. What is a Prokaryotic Cell? 2. What is a Eukaryotic Cell? 3. What is a Virus?		1. Killer Cocci 2. Gruesome Gram-positive Bacilli 3. Nasty Gram Negative Bacilli 4. The Squiggly Wiggly Bad Guys 5. DNA Viruses 6. RNA Viruses
Microbes Aren't All Bad!		Lab Procedures
1. Probiotics and Normal Flora 2. Bioremediation 3. Making Food and Beverages 4. Genetic Engineering 5. The Circle of Life		1. The Gram Stain 2. Specialized Media
Specific Microbial Diseases		Just for Fun
1. Tetanus 2. Syphilis		1. Sandbox 2. Humor 3. Student spotlights
Microbes in the Media		Special Reports
1. Cool Things with Microbes 2. Diseases in the Media 3. Swine flu updates		1. Microbiology in Your Career 2. Maggot Therapy
Class Logistics		Other Online Resources
1. Homework, Assignments, and Exam Schedule 2. Communications from Kevin 3. Discussion Board 4. Lecture Recordings 5. Test Prep and Study Tips

Unrelated to Swine flu, but very interesting, super-sized Mimivirus has been photographed in great detail!

	The Microbiowiki was originally created by students and their teacher in Provo and Brigham City, Utah between Jan and April 2008. It is currently being modified by new students. We are using Foundations in Microbiology, by K. Talaro, 6th edition (ISBN-13: 978-0073305400). If you have the 5th or 7th editions, that is fine. I will be posting messages to the students here on a regular basis. People outside of our class are also welcome to participate in this wiki. ~Kevin Check out recent activity on the What's New page or the Discussion Board.

Harvard has made available many short movies of bacteria moving. They are taken with fluorescence microscopy and you can really see the flagella well. Very cool! Breaking News (12 Jan 09). Peanut butter recall in response to widespread Salmonella poisoning. Experimental Evidence that sleeping more reduces your risk of catching a cold! The study concluded that "those who got less than seven hours of sleep a night were almost three times as likely to have clinical symptoms as those who got eight or more" (I typed this at 1 AM. Oops!) Anti-bacterial soap...new findings suggest that it might not be as safe as we thought. Some of the chemicals found in it may affect sex hormones, interfere with the nervous system, and may even cause Autism in children. Click on this link to read the details! http://www.webmd.com/news/20080529/safety-debate-on-antibacterial-soap Fighting a deadly Superbug....MRSA in hospitals, what medical personal can do to prevent the spreading of MRSA, proper techniques of disposing of gowns, gloves ect. (see also video of IMPROPER techniques I found on a You Tube video of Maggot Therapy-see Microbes in Media section for that video) http://www.comcast.net/data/fan/html/popup.html?v=1068838094
If you are in Logan or Brigham City, here is the link to Dr. Kaiser's Lab Manual, that we will be using (no labs in Provo). It's a pretty big file, so be patient with the download. You can save a copy on your computer and just print out the pages as you need them, or you could take the file to a printer and have the whole thing printed and bound. . . however you want to do it will end up cheaper than if you bought a lab book from a publisher. Thanks Dr. Kaiser for letting us use this!
There are pdf files of lecture slides posted on Blackboard. There are also lecture notes there (and at the bottom of this page).
You can find flash cards made by others or create your own at Flash Card Exchange. If you decide to create some flash cards, please post links to them on the appropriate pages here (ask me if you need help with this).

Inner Life of the cell:

Also of interest

Benefits of Bacteria

flattail — Tue, 11 Aug 2009 22:03:13 CDT

A new skincare product line, called Nude, uses pre and pro-biotics!

Beneficial Bacteria? 7 Amazing Jobs Your Gut Bacteria Do

Trillions of microbes live inside you. But don't be frightened; some bacteria do good things

By Katherine Hobson

Posted February 2, 2009

Don't look now, but your gut is teeming with microbes—as many as 100 trillion of them. It may unnerve you to know that you're providing a home to a population of bacteria and other tiny organisms, but they're not just squatters; some beneficial bacteria help you digest food and can protect against infection. Scientists are also discovering that the microbes, which vary in makeup from person to person, may influence a host of physiological processes that at first glance have little to do with the digestive system. The National Institutes of Health in 2007 launched the Human Microbiome Project, which will sequence the genomes of hundreds of different human-dwelling microbes, so the research into these critters will only continue. But we already know, suspect, or theorize they have the ability to:

1. Influence disease in your gut. It's probably not so surprising that the gut microbes affect the organ in which they live; indeed, bacteria in the gut send signals to various stomach and intestinal cells and vice versa, says Emeran Mayer, director of the Center for the Neurobiology of Stress at UCLA. Microbes are suspected to play a role in inflammatory bowel disease, including Crohn's disease and ulcerative colitis, for example. Research in mice published last year suggested that while one strain of bacteria, H elicobacter hepaticus, can promote IBD when introduced into the digestive tract, a molecule produced by another strain of bacteria, B acter oi des fragilis, may signal immune cells to suppress the disease's characteristic inflammation.

2. Give you the stomach-flu blues. "Most people who have severe gastroenteritis know that it has a major effect on your well-being," says Mayer. But on top of the obvious unpleasantness of their diarrhea and nausea, sufferers often withdraw socially, don't want to do anything, and are generally bummed out. It's still in the realm of theory, but it's possible that the gut bacteria could be talking to your so-called vagal nervous system, which sends signals from the gut to the brain. If microbes "speak" to any of the thousands of sensory nerve cells that lie within the gut walls, either directly or through nearby cells, it might influence your emotions. (Evidence that supports such a mechanism has been found in rodent experiments.) "Is our general sense of well being due to this bacterial-to-vagal system?" wonders Mayer. For now, it's speculation, but planned studies with brain imaging may shed some light on the notion.

3. Influence asthma and allergies. Gut bacteria are also thought to influence the immune system, says Les Dethlefsen, a researcher at Stanford University. Too much of one kind of immune response—led by Th1, or T-helper cells 1—has been associated with autoimmune diseases, while an overactive response led by another kind of immune cell, Th2, can result in allergies. Certain normal gut bacteria are known to influence the balance of the two responses, and some studies have associated changes in the gut bacteria with an increased risk of allergies.

4. Play a role in obesity. The particular mixture of microbes in your gut may be influencing your ability to absorb nutrients from food and, thus, your tendency to gain weight. Research suggests that the obese are home to different microbe populations from the thin, though it's not yet known whether the variations cause the weight differences or whether the same diet or other factors that contribute to obesity also change the bacterial population. There are hints of a causal role; one recent study by researchers in Arizona suggests that certain microbes that improve nutrient digestion, and are present in about 10 percent of the population, occur almost exclusively in the obese and not in people who are normal weight or who have had gastric bypass surgery. Despite the accumulating evidence, though, the field is still in its infancy, says John DiBaise, a gastroenterologist at the Mayo Clinic in Arizona and an author of the study. That means it's far too early to try to manipulate your own gut bacteria through probiotics or prebiotics with an eye to losing pounds.

5. Cut the risk of developing painful kidney stones. One microbe, Oxalobacter formigenes, can break down the substance that makes up most kidney stones, calcium oxalate. Last year, researchers from Boston University reported that people with the O. formigenes bug in their guts had a 70 percent lower risk of kidney stones. It's not clear yet whether those without naturally occurring O. formigenes could reduce their risk by ingesting the bacterium, but researchers are looking into it.

6. Affect cancer risk. Microbes living in the gut may play a role in cancer—for good and for bad. H. pylori , for example, is linked to ulcers and stomach cancer but may have a protective role, too, fighting gastroesophageal reflux disease, or GERD, and one potential complication, a type of esophageal cancer. Meredith Hullar, a scientist at the Fred Hutchinson Cancer Center in Seattle, is part of a team looking at how diet and gut microbes might interact to alter one's cancer risk. Some of the chemicals called isoflavones, found in soy, can be metabolized by certain gut bacteria into a compound called equol that may play a role in cancer prevention, Hullar says. (Equol binds to estrogen receptors in the body and reduces exposure to the actual hormone, lowering the risk of some forms of breast and other cancers.) "You either have those bacteria or you don't," says Hullar. Cooked broccoli may contain another compound that requires certain bacteria to digest it into cancer-preventing components.

7. Help out someone else. The obvious question is whether it's possible to fight disease or improve bodily function by altering an individual's microbe population, which is thought to stay fairly stable from early childhood to old age. Research into the potential of both diet and probiotic or prebiotic supplements to manipulate the makeup of the gut microbiome is ongoing; scientists say there's far more to learn about the diversity and function of bacteria. But in extreme cases of illness brought on by a severe, recurrent infection by the bacterium C. difficile, the healthy balance of gut bacteria can be restored by a gross-sounding sort of procedure called a fecal transplant. A healthy person "donates" his or her normally functioning gut bacteria via filtered stool, which is inserted into the infected person by enema or using a tube snaking down the nose and into the gut.

Microbes in the Media

flattail — Tue, 11 Aug 2009 19:37:15 CDT

This page needs to be reorganized! We should have subpages for
1. Cool Things with Microbes
2. Diseases in the Media
3. Swine Flu Updates
4. Benefits of Bacteria

Vitamin B Makes bacteria generate more electricity

Kombucha Benefits

WHY IS H-PYLORI MORE COMMON IN PEOPLE WITH TYPE O BLOOD? According to the New York Times it is because the antigens on RBC's and the stomach cells of people with type A, B, or type AB have different chemistry than those of people with O blood so as a result people with O blood type have more receptors for the H-pylori bacteria. Ulcers are 1.5-2 time more common in people who are type O. For more info go to www.nytimes.com
FUN FACTS ABOUT H-PYLORI

in the US 20 % of the population is infected by the time they are 20, and 50% of people 60 and older have had h-pylori, and worldwide 80% of the population is infected by the time that they are 10
for nearly 100 years scientist and doctors thought that ulcers were caused by spicy foods, stress, and alcohol, and to much stomach acid, it wasn't until 1982 that it was discovered to be caused by a bacteria.

Salmonella blamed for killing dozens of Utah birds

April 20th, 2009 @ 10:03pm

By Whit Johnson

SALT LAKE CITY -- A growing number of common backyard birds are dying, and experts are blaming salmonella. The event is occurring nationwide, but there have been at least a couple dozen reported cases in Utah. Experts say some of us are making the problem worse. The Pine Siskin is smaller than the House Finch and usually has yellow and dark streaks down its body. These birds are common in Utah, but now they're running into trouble. "Some birds recover, get better and move on, and some birds don't," said Bill Fenimore, owner of the Wild Bird Center of Layton.

Experts believe birds become infected with the salmonella when they eat birdseed that has come in contact with their droppings.

Across the Wasatch Front, there have been at least 30 reports of Pine Siskins dead from salmonella. Fenimore says the birds are likely infecting each other around feeders. "They gather around in large flocks and as they defecate and that falls onto the ground, any seed that may fall on the ground can become contaminated with those droppings," Fenimore said. "What happens is the bacteria gets built up on their bird food and then it goes from one bird to the next," explained. Leslie McFarlane, with the Utah Division of Wildlife Resources. DWR has been watching the problem since dead bird reports began popping up in Idaho. Experts say when the birds are sick, they become lethargic, more approachable and their wings may droop. "They get really thirsty, so you'll see them maybe around your bird baths and things like that," McFarlane said. Experts say clean your bird feeders frequently with a 10 percent bleach solution, replace old bird seed and rake up seeds that may have fallen on the ground below. "It's kind of like if we went to the Jazz game and there's 14,000 screaming fans, every once and a while you'll notice someone sneezing, coughing and shaking hands with other people," Fenimore said. Experts believe the salmonella is not coming from the bird seed itself. They also say it's important to keep your bird feeders clean to protect your pets and young children.

Cool articles relating to bacteria and viruses

Bacteria Invade Genomes	Do bacteria crave chocolate?	Studies show that bacteria are common in the snow
Bacteria still alive-after 8 million years!	Probiotics and your metabolism	Bacteria fool immune system with human-like proteins
Yet another E. coli meat recall	New Bacteria Strain is Striking Gay Men in San Fansisco, and Boston	Day Care, Siblings, and Asthma--Please Sneeze on My Child (New England Journal of Medicine)
Viruses useful in wound treatment	New way to control a parasitic ameba that kills and eats human cells	Drugs on tap -- in our drinking water
Mousepox "SuperBug" Test Riles	Six Gym Health Hazards	Killing cancer cells
Dirty Lemons: a restaurant threat	Frog skin to the rescue!	Finding a breakthrough on bird flu
The Wonderful World of E. coli	Do antibacterial wipes spread more bacteria?	Montana cow tests positive for brucellosis
Clostridium difficile become even more difficult	Did the Tomato Scare Start with Excessive Hygiene?	Zapping HIV with lasers
Was this the mastermind behind the anthrax killings or an innocent victim of innuendo?	Is this excessive hype or sound government advice?	"Sputnik" virushijacks other viruses!
New bacterial species found in human mouths	People exposed to 1918 flu virus as children are still immune to it in their old age	"Sniffer rats" can detect tuberculosis with much greater speed than other methods!
5 Next Generation antibiotics that may save your life!	Can Malaria be eradicated in 10 years??	Honey effective in killing bacteria, even biofilms!
'Friendly' Bacteria Protect Against Type 1 Diabetes	Enoki Mushrooms Contaminated with Listeria Recalled	AIDS cured after bone marrow transplant
Chicken Pox Parties	Beneficial Bacteria	Number of Utah RSV cases triples in one month Human respiratory syncytial virus(RSV) is a negative-sense, single stranded RNA virus of the family Paramyxoviridae, which includes common respiratory viruses such as those causing measles and mumps. RSV is a member of the paramyxovirus subfamily Pneumovirinae.
Vitamin D lowers risk of respiratory infections	Platelets help control malaria	AIDS cured after bone marrow transplant!
Remember the catalase test? And that your own cells produce catalase? Well, it looks like catalase production decreases as we age, which explains why your hair goes gray!	Ancient Microbes Found
This video is on Maggot Therapy used to help treat MRSA, however, the reason I posted this video pertains to the improper MRSA preventing techniques the Doctor exhibited while treating this patient. Notice at the beginning that the Dr.'s gloved hand leaves the screen and seems to have gone to his face, like he wiped his brow or something. Then notice when he takes one of his gloves off, how he touches the other glove, handles a syringe with his bare hand contaminating his free hand and probably his nose since he seemed to keep touching it. This is one of the biggest problems today in fighting the battle with MRSA (or any other infectious bacteria): the lack of proper handling or disposing of contaminated gloves, gowns, etc by medical personnel! This is one of the main causes of this bacteria spreading. There is also a news video from CBS on this very problem, It cannot be embedded here, but you can watch "Fighting a deadly superbug" by clicking on the link.		Here is a video on maggot therapy that does more to show the actual use of maggots (amazing how quickly they grow!)
colonoscopy patients have hepatitis	Is there danger lurking in your lunch?
Playing in the dirt may lift your seratonin levels	Hospital workers and mobile phones, "superbug" scare	Evolution-proof Insecticides May Stall Malaria Forever
Lizard blood kills spirochete that causes Lyme disease!	Great article about Craig Venter making synthetic life and being amazed by what real microbes can do	Novel treatment of Staph infections using nanoparticles to deliver Nitrous Oxide
Article discussing reasons to vaccinate your children--do you agree?	Interesting article on biofilms in Discover magazine	Treating Staph infections with bacteriophages

Bed Bugs
Here is a video showing how Utah is trying to save money by using bacteria to help improve the water treatment plants. Very interesting. Methane gas producers.

The Human Gut Is A Real Melting Pot

Talk of the Nation, November 21, 2008 · Scientists found 5,600 different species or strains of bacteria living in human intestines, making gut bacteria 10 times more diverse than expected. David Relman, one of the authors of the study, explains the findings and how a common antibiotic disrupts this bacterial community.

To have a listen go here: http://www.npr.org/templates/story/story.php?storyId=97303406

Stomach Bacteria Could Prevent Asthma

Talk of the Nation, July 18, 2008 · Several years ago, researchers proposed the provocative idea that bacteria living in the human stomach could be responsible for the development of some stomach ulcers — and the doctors found that treating those bacteria, H. pylori, with antibiotics could reduce ulcer risk. New research suggests, however, that those bacteria may not be all bad — they could help prevent the development of childhood asthma.

To have a listen go here: http://www.npr.org/templates/story/story.php?storyId=92677188

Gut Bacteria May Cause And Fight Disease, Obesity

Who lives here in the large intestine? What do they do?

All Things Considered, November 4, 2008 · Quick question: Whose genes matter most to you? Your mom's? Your dad's? Or genes inside the trillions of bacteria living in your intestine, your mouth, your nasal passages and a lot of places we'd rather not mention? The answer: Obviously, your parents' genes matter, but it turns out we humans have two sets of genes in us: the ones we inherited from our human ancestors and the ones that walk in through our mouths starting when we're just hours old.

To read more or to listen, go here: http://www.npr.org/templates/story/story.php?storyId=95900616

Bacteria, Where Would We Be Without You?

Talk of the Nation, January 26, 2007 · Without bacteria, we probably wouldn't be here. Infections can help as well as harm us. Joe Palca talks about infection — both the good and the bad — with researcher and writer Gerald Callahan, the author of Infection: The Uninvited Universe.

To listen, go here: http://www.npr.org/templates/story/story.php?storyId=7039533

Sick of Getting Sick? Embrace Your Inner Bacteria! by Deborah Franklin

Morning Edition, August 24, 2006 · No one has time to be sick anymore, not even for a fiercely raw throat or a nasty sinus infection. But will an antibiotic help or hurt? The answer depends on how your garden grows.

To read or listen to more, go here: http://www.npr.org/templates/story/story.php?storyId=5697054

Enjoy! I love NPR and have been a fan for years. There's plenty more out there if you care to search for them.
Bacteria are found thriving beneath Antarctic glacier

Cold, dark » They have survived millions of years, living on sulfur and iron compounds.

By Randolph E. Schmid
The Associated Press

Updated: 04/18/2009 06:00:08 PM MDT

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Click photo to enlarge

** EMBARGOED UNTIL 2:00 P.M. THURSDAY, APRIL 16, 2009 ** This undated... (The Associated Press)

Washington » Hidden in the bone-chilling dark beneath an Antarctic glacier, a colony of strange bacteria is thriving.
Scientists investigating the flow of blood-red water from beneath the glacier discovered the bacteria, which have survived for millions of years, living on sulfur and iron compounds, they report in Friday's edition of the journal Science .
"Among the big questions here are: 'How does an ecosystem function below glaciers?', 'How are they able to persist below hundreds of meters of ice and live in permanently cold and dark conditions for extended periods of time, in the case of Blood Falls, over millions of years?" said lead researcher Jill Mikucki, of Harvard University.
Blood Falls, flowing from beneath Taylor Glacier, has long evoked curiosity because of its color. The researchers determined that iron compounds provide the color, and in the process of their research they discovered bacteria in the water, an extremely salty pool.
John Priscu, of Montana State University, said that because the ecosystem has been isolated for so long in extreme conditions, it could help explain how life might exist on other planets, and serve as a model for how life can exist under ice.
The researchers believe the pool of water was trapped about 1.5 million years ago when the glacier moved over a lake. It doesn't freeze because it is four times saltier than the ocean.
The pool is so deep under the ice and so far back from the edge that the researchers couldn't drill down to it, but they were able to collect some of the outflow for testing.
"When I started running the chemical analysis on it, there was no oxygen," Mikucki said. "That was when this got really interesting, it was a real 'eureka' moment."
Most of the bacteria she found were descended from marine microorganisms -- not from those found on land -- and they were able to live without the food and light sources of the open ocean.
The researchers concluded that the ancestors of the bacteria probably lived in the ocean millions of years ago and when the Antarctic valleys rose, a pool of seawater was trapped and was eventually capped by the flow of the glacier.
The research was funded by the National Science Foundation, Canadian Institute for Advanced Research, Harvard Microbial Sciences Initiative and the National Aeronautics and Space Administration.

You can listen to Microbial Podcasts

Latest Microbial News from the New York Times

Latest Microbial News from Science Daily

Mousepox 'Superbug' Test Riles

flattail — Wed, 24 Jun 2009 15:14:56 CDT

SAN FRANCISCO, Nov. 1, 2003

(Photo: AP)

“The whole focus was to contribute to the biodefense agenda of the country.
Mark Buller
research team head

(AP) A research team backed by a federal grant has created a genetically engineered mousepox virus designed to evade vaccines, underscoring biotechnology's deadly potential and stirring debate over whether such research plays into the hands of terrorists.

The team at Saint Louis University, led by Mark Buller, created the superbug to figure out how to defeat it, a key goal of the government's anti-terrorism plan.

The researchers designed a two-drug cocktail that promises to defeat their exceptionally deadly virus. They hope to publish their work soon in a peer review journal.

“The whole focus was to contribute to the biodefense agenda of the country,” Buller said.

Buller spliced a gene known to suppress the immune system into the mousepox virus, then injected the combined strand into vaccinated mice. All of them died.

Mousepox can't be passed to humans, but it's a close relative to smallpox, making it an ideal virus to study in animals.

The research highlights a contentious discussion among scientists and security experts: Does publication of such work help or hinder the biodefense effort? Should such studies be conducted at all?

In response to heightened security concerns, many scientific journals have censored studies with national security implications. When Buller presented his results last week at an international biodefense conference, it prompted debate.

Some feared that publication of such information, regardless of whether scientists' intentions are altruistic, could help terrorists create biological weapons laced with genetically modified superbugs. Such germs are created by splicing drug-resistant genes in viruses normally defeated by vaccines.

“In the Soviet Union, there was some research trying to develop genetically engineered smallpox,” said Ken Alibek, a former top scientist in the Soviet biological weapons program who came to the United States in 1992. “It wasn't very successful, but now with all the new advances in technology, know that it's pretty much obvious that it can be done.”

Alibek, a director of George Mason University's National Center for Biodefense, believes Buller's work and similar research should be confidential to impede terrorists and rogue nations from acquiring knowledge about genetically engineered bioweapons.

Buller counters that publicizing such work will deter terrorists by showing that scientists can build defenses against souped-up bioweapons. Buller also believes scientists must genetically engineer pathogens to understand how to defeat them.

“All this is out there,” Buller said of bioweapons research. “There are cookbooks easily attainable on how to make this stuff.”

Buller said his work replicated a nearly 3-year-old Australian study, which the scientific community continues to debate.

In that study, scientists trying to beat back an overabundance of mice in Australia spliced a single foreign gene into a typically mild mousepox virus in hopes of creating a genetically engineered sterility treatment. Instead, they created a mousepox strain so powerful that it killed even those mice inoculated against the virus.

Buller's team improved upon the Australian accident, said Larry Kerr of the White House Office of Science and Technology Policy.

“They did a more thorough analysis,” Kerr said. “It's more substantive and it went a step further: They developed a counter measure.”

Buller said infected mice recovered when treated with a combination of anti-viral drugs, providing hope that a treatment against genetically engineered smallpox could be developed.

Smallpox historically kills about a third of its victims and can be transmitted from person to person, unlike anthrax and other biological weapons.

Smallpox has plagued humans for centuries, and it's believed to have killed more people than all wars and epidemics combined. Death typically follows massive hemorrhaging.

Kombucha group project

flattail — Wed, 24 Jun 2009 15:10:55 CDT

Kombucha

The History Of Kombucha

Kombucha dates back to the Qin Dynasty in China. The Chinese called this drink "the immortal health elixir." It was said to aid in digestion and allow the body to focus on healing. Kombucha eventually reached Russia and Europe.

What is it?

Kombucha contains many different cultures along with several organic acids, and polyphenols. Depending on how the Kombucha is made it may also contain B vitamins.

Health Benefits of Kombucha

People who drink kombucha report benefits like enhanced wellbeing, increased energy and even weight loss. Research has shown that kombucha may have anti-microbial effects against harmful bacteria like E. coli, a range of vitamins and minerals, and possibly anti-fungal properties as well

Cool Things with Microbes

flattail — Wed, 24 Jun 2009 15:07:58 CDT

There is no abstract available for this page revision.

Diseases in the Media

flattail — Wed, 24 Jun 2009 15:07:27 CDT

There is no abstract available for this page revision.

Swine flu updates

flattail — Wed, 24 Jun 2009 15:05:28 CDT

Feel free to post links to articles you find important, or embed websites into this table. You can also get breaking news at the World Health Organization (WHO) website.

	11 June. It's official! Swine flu declared a pandemic! Fortunately mortality rate in the first 28,000 cases has been only 0.5% (99.5% you would survive if you got this disease). Still, if it spreads widely enough it could have a large total impact. "A move to level 6 is not a verdict on the severity of the virus," she said. "It simply means that the extent of global spread now fulfills the definition of a pandemic."
Swine Flu update as of April 30, 2009 7:00 AM ET
Utah has plan in place to deal with swine flu
US declares swine flu public emergency	click here to read news story on deadly flu outbreak!	Origin of Swine Flu Discovered!

April 28, 2009 11:00 AM ET

U.S. Human Cases of Swine Flu Infection
(As of April 28, 2009 11:00 AM ET) State # of laboratory
confirmed cases

California	10 cases
Kansas	2 cases
New York City	45 cases
Ohio	1 case
Texas	6 cases
TOTAL COUNT	64 cases
International Human Cases of Swine Flu Infection See: World Health Organization

The human swine flu outbreak continues to grow in the United States and internationally. Today, CDC reports additional cases of confirmed swine influenza and a number of hospitalizations of swine flu patients. Internationally, the situation is more serious too, with additional countries reporting confirmed cases of swine flu. In response to the intensifying outbreak, the World Health Organization raised the worldwide pandemic alert level to Phase 4 . A Phase 4 alert is characterized by confirmed person-to-person spread of a new influenza virus able to cause “community-level” outbreaks.” The increase in the pandemic alert phase indicates that the likelihood of a pandemic has increased. CDC has activated its emergency operations center to coordinate the agency’s emergency response. CDC ’s goals are to reduce transmission and illness severity, and provide information to help health care providers, public health officials and the public address the challenges posed by this swine influenza virus. Yesterday, CDC issued a travel warning recommending that people avoid non-essential travel to Mexico. CDC continues to issue interim guidance daily on the website and through health alert network notices. CDC’s Division of the Strategic National Stockpile (SNS) is releasing one-quarter of its antiviral drugs, personal protective equipment, and respiratory protection devices to help states respond to the outbreak. The swine influenza A (H1N1) virus is susceptible to the prescription antiviral drugs oseltamivir and zanamivir. This is a rapidly evolving situation and CDC will provide updated guidance and new information as it becomes available.

Just in 04/24/09: DEADLY NEW FLU BREAKS OUT IN MEXICO, US!!

This just in... Updated today. The fear is it's already spread to Texas and California. This strain is unique in that it is infecting people who have never worked on a farm. And in that it is a mixture of Avian, swine and human flue strains... from all over the world Asia and Eurpoe to mention a few. It does however seem to respond to meds.

MEXICO CITY – Mexico City is suspending all public events for 10 days as officials try to contain an outbreak of a deadly new swine flu. Mayor Marcelo Ebrard says the city has enough medicine to treat those infected, but the city's focus is on containing the spread of the strain. City Health Secretary Armando Ahued says 10 new possible cases of infection have been discovered. Officials say some 1,004 people have been infected nationwide. Tests show 20 people have died of the swine flu, and 48 other deaths were probably due to the same strain. The H1N1 virus is a mix of human, pig and bird viruses that has epidemiologists around the world deeply concerned. The World Health Organization says the outbreak has "pandemic potential."

Final Exam Study Guide

flattail — Tue, 23 Jun 2009 16:21:51 CDT

Main Concepts By Chapter

PROVO CLASSMATES!!

The final exam will focus on material primarily from the first four tests, but with some questions on the newer material as well. There will be at least 1 question from each chapter that you have seen previously on a test. As I said, at least 20 of your questions will be familiar to you.

Topics to Review

Chapter 1

Prokaryotes vs Eukaryotes

what are the major differences between the groups?
What are some major groups of eukaryotes?
Is a protozoan a eukaryote or a prokaryote?

Infectious diseases and the human condition

Statistics of worldwide infections
How have microbes changed over time?
How have people and society changed over time?

Major contributors to the history of microbiology

Contributions of Antonie van Leeuwenhoek, Louis Pasteur & Robert Koch
Semmelweis and Lister and aseptic techniques

Chapter 3

Variations of light microscopes

Bright field, dark field, contrast, fluorescent

Types of stains

Simple, differential, special (pg 85)

What type of stains are Gram stain and acid fast stain?

"Five I's"

What is involved in Inoculation, Incubation, Isolation, Inspection, Identification?

Chapter 4 (Procaryotic Cell Structures)

Bacterial Appendages

What are the roles of pili, flagella, fimbrae

Cell envelope

What are the components of the cell envelope and the function of the major parts?

Cell wall

Understand the structure of the cell wall
What are the differences between gram-positive and gram-negative cell walls?

Cell membrane

What's up with the phospholipid bilayer?

Chapter 18: Cocci of medical importance

Staphylococcus and Streptococcus

How do you differentiate between these groups? (catalase test)
How can you differentiate between S. aureus and other Staph?
What are some of the major virulence factors for S. aureus?

Group A strep (Streptococcus pyogenes)

Major virulence factors and diseases

Rheumatic fever and heart troubles

Streptococcus pneumoniae

What is bacterial pneumonia?

Neisseria (a gram-negative coccus)

gonorrhea
meningitis (N. meningiditis)

Chapter 5: Eucaryotic Cells

What are the major groups (kingdoms) of eucaryotes?
What is the endosymbiotic theory?

Who discovered this?
Chloroplasts: what are they and what is their role?

Locomotor appendages

Cilia versus flagellae

Chapter 6: Intro to viruses

Classification of viruses (DNA, RNA)
How to culture viruses in the lab

Role of chicken embryos and other animal tissues

How to make a vaccine against a virus
Animal virus replication

adsorption, penetration, replication, assembly, release

Chapter 7: Microbial nutrition, ecology, and growth

Nutritional categories of microbes

autotrophs versus heterotrophs?

Adaptability of microbes to the environment

pH, oxygen, temperature, other organisms, water, etc.

Nutrition of microbes

macronutrients versus micronutrients
inorganic nutrients versus organic nutrients

Cellular transport

diffusion, facilitated diffusion, osmosis, active transport, phagocytosis

Chapter 19: Gram-positive bacilli of medical importance

The endospore formers: Bacillus and Clostridium

Bacillus: aerobic; B. anthracis
Clostridium: anaerobic; botulism, gas gangrene, and tetanus. Also, C. difficile

Acid-fast staining: the Mycobacteria

Chapter 8

What are the differences between enzymes, coenzymes, cofactors, and substrates?
The basic pathways of the oxidation of glucose (glycolyis, TCA or Kreb's Cycle, and ETC)
What are the differences between aerobic and anaerobic respiration.

What is the difference between anaerobic respiration and fermentation?

Chapter 9

Be able to define: genetics, heredity, genome, chromosome, gene, DNA, and protein

Understand the structure of DNA (string of nucleotides; adenine pairing with thymine, guanine pairing with cytosine)

Understand difference between DNA and RNA (and structurally RNA contains uracil instead of thymine)

What is an intron?
What is an operon?
Understand some of types of genetic mutations

missense, nonsense, point mutations, frame shifts

What does an Ames test measure?

Chapter 11

Physical methods for controlling microbes

moist heat, dry heat, radiation, cold temp, filtration, and dessication

What are the effects of chemicals on the cell wall and the cell membrane?

How do the chemicals break these down?

Thermal death point versus thermal death time: how are these defined?

Chapter 20: Gram-negative bacilli of medical importance

Endotoxic shock (pg 601) due to lipid A
Pseudomonas: aerobic, multi-drug resistant; biofilm former
Escherichia: facultative anaerobe. E. coli O157:H7, nosocomial infections (UTI)
Salmonella: facultative anaerobe; GI infections (including typhoid fever); role of poultry
Yersinia pestis: facultative anaerobe; plague; role of fleas and rodents, and the enzyme coagulase

Chapter 12

Five targets of drug action

cell wall, cell membrane, DNA & RNA, protein synthesis, and metabolic pathways

Tests for drug susceptibility

Kirby-Bauer, MIC and Therapeutic Index (TI)

Mechanisms of drug resistance

drug inactivation, decrease in permeability, change of drug receptors, biofilms, and enzymes to break the drug

Chapter 13: Microbial-human interactions

Normal flora of GI tract, skin, mouth, genitals

Role of normal flora in preventing some infections and causing others (super infections)

Lipid A of Gram-negative cell walls and endotoxic shock
Different portals of entry and exit (skin, respiratory tract, digestive tract, genitals, etc)

Chapter 14: Nonspecific host defenses

First, second, and third lines of defense

What are the components of each?

Different cell types of second line of defense

relative percentages of different cell types and what their roles are (e.g. neutrophils, basophils, eosinophils, etc)

Inflammatory response

rubor, calor, dolor,
general mechanisms and results of inflammation

Chapter 15

What are antigens?
T-cells versus B-cells

Where are they formed? Where do they mature?
What are their functions?

Antibodies

Plasma cells, memory cells
Classes of antibodies (e.g. IgA, IgG, IgE)

Classification of acquired immunity

natural, artificial, passive, active

RNA Viruses

flattail — Tue, 23 Jun 2009 16:21:23 CDT

The RNA Viruses that Infect Humans

Virus Classification

Group: Group V ((-)ssRNA)

Family: Orthomyxoviridae
Genera

Influenzavirus A
Influenzavirus B
Influenzavirus C
Isavirus
Thogotovirus

Orthomyxoviruses

• Enveloped, segmented ssRNA
• 2 types of enveloped glycoprotein spikes
– Hemagglutinin (HA) – binds to host cells
– Neuraminidase (NA) – hydrolyzes mucus & assists viral budding & release
• Genome constantly changes
– Antigenic drift -minor change caused by mutations
– Antigenic shift -major alteration occurring when segments recombine

Q: What are hemagglutinin and neuraminidase?
a. Exotoxins produced by the influenza virus
b. Glycoprotein receptors on influenza's target cells
c. Glycoproteins on influenza virus that contribute to virulence
A: Glycoproteins on influenza virus that contribute to virulence

Influenza type A
• Acute, highly contagious respiratory illness
• Seasonal, pandemics • Among top 10 causes of death in US
• Respiratory transmission
• Binds to ciliated cells of respiratory mucosa
• Causes rapid shedding of cells, stripping the respiratory epithelium, severe inflammation fever, headache, myalgia, pharyngeal pain, shortness of breath, coughing
• Treatment: amantadine, rimantadine, zanamivir & oseltamivir annual trivalent vaccine

Tested by inserting a swab into the nasopharyngeal area and testing the mucus on the swab. It can also be detected using what is called a nasal wash (shown below) where approximately 1 cc of saline is placed into a syringe with a hose attached to the syringe. (where the needle would be) The tubing is then placed up the nostril and the saline is shot up into the nostril. The saline is then sucked back into the syringe, collecting mucus in the process. Afterwards the solution is sent to the lab for testing. These tests can be performed to detect Influenza A and B. In the state of Utah if a Influenza B is detected it is sent to the State lab for verification.

Pandemics
Flu spreads around the world in seasonal epidemics, resulting in the deaths of hundreds of thousands annually — millions in pandemic years. Three influenza pandemics occurred in the 20th century and killed tens of millions of people, with each of these pandemics being caused by the appearance of a new strain of the virus in humans. Often, these new strains result from the spread of an existing flu virus to humans from other animal species. An avian strain named H5N1 had until recently posed the greatest risk for a new influenza pandemic since it first killed humans in Asia in the 1990s. Although H5N1 virus has not mutated to a form that spreads easily between people, in April 2009 a novel H1N1 flu strain that combined genes from human, pig, and bird flu, initially dubbed the "swine flu," emerged in Mexico, the United States, and several other nations. By late April, the H1N1 swine flu was suspected of having killed over 150 in Mexico, and prompted concern that a new pandemic is imminent.
The 2009 flu outbreak in humans that is widely known as "swine flu" apparently is not due to a swine influenza virus. It is due to a new strain of influenza A virus subtype H1N1 that derives from one strain of human influenza virus, one strain of avian influenza virus, and two separate strains of swine influenza virus. The origins of this new strain are unknown, and the World Organization for Animal Health (OIE) reports that this strain has not been isolated in swine. It passes with apparent ease from human to human, an ability attributed to an as-yet unidentified mutation. The strain in most cases causes only mild symptoms and the infected person makes a full recovery without requiring medical attention and without the use of antiviral medicines.

Reassortment: most important for pandemic influenza viruses
It is the mixing of the genetic material of two similar viruses that are infecting the same cell. In particular, reassortment occurs among influenza viruses, whose genomes consist of eight distinct segments of RNA. These segments act like mini-chromosomes, and each time a flu virus is assembled, it requires one copy of each segment.
If a single host (a human, a chicken, or other animal) is infected by two different strains of the influenza virus, then it is possible that new assembled viral particles will be created from segments whose origin is mixed, some coming from one strain and some coming from another. The new reassortant strain will share properties of both of its parental lineages.
Reassortment is responsible for some of the major genetic shifts in the history of the influenza virus. The 1957 and 1968 pandemic flu strains were caused by reassortment between an avian virus and a human virus, whereas the H1N1 virus responsible for the 2009 swine flu outbreak had an unusual mix of swine, avian and human influenza genetic sequences.

1918-1919 Flu Pandemic
-One out of every five people on earth were infected, with a 2.5% mortality rate (typical influenza is less than 0.1% fatal).
-The disease progressed very quickly and was sometimes fatal within hours.
-Some believe it to have been the avian flu
-It was most deadly for people between the ages of 20-40 years old which is an unusual pattern for influenza.
-675,000 Americans died which was 10 times more than in WWI.

This link has the full history of the1918 flu pandemic, incredible!

http://health.discovery.com/centers/coldsflu/germs/influenza.html

Q: What type of vaccine is the current flu vaccine?
a. Recombinant
b. Killed, whole virus
c. Toxoid
A: Killed, whole virus

Avian Influenza A (H5N1) Bird Flu
Influenza A (H5N1) is an influenza A virus subtype that occurs mainly in birds. It is highly contagious among birds and can also be deadly to them.
H5N1 virus usually does not infect humans but have on rare occasions. Most of these cases have been from direct or close contact with infected poultry. There is no immune protection against the human population. Infected birds shed influenza virus in their saliva, nasal secretions, and feces. Susceptible birds become infected when they have contact with contaminated secretions or excretions or with surfaces that are contaminated with secretions or excretions from infected birds. Domesticated birds may become infected with avian influenza virus through direct contact with infected waterfowl or other infected poultry, or through contact with surfaces (such as dirt or cages) or materials (such as water or feed) that have been contaminated with the virus.
Infection with avian influenza viruses in domestic poultry causes two main forms of disease that are distinguished by low and high extremes of virulence. The “low pathogenic” form may go undetected and usually causes only mild symptoms (such as ruffled feathers and a drop in egg production). However, the highly pathogenic form spreads more rapidly through flocks of poultry. This form may cause disease that affects multiple internal organs and has a mortality rate that can reach 90-100% often within 48 hours.

Mumps

• Epidemic Parotitis
• Self-limited, associated with painful swelling of
parotid salivary glands
• Humans are the only reservoir
• 40% of infections are sub-clinical
• 300 cases in US/year
• Incubation 2-3 weeks fever, muscle pain & malaise,
classic swelling of both cheeks
• In 20-30% of infected males, epididymis & testes become
infected; sterilization is rare
• Live attenuated vaccine MMR

Measles
• Caused by Morbillivirus
• Also known as red measles & rubeola
• Different from German measles
• Very contagious
• Transmitted by respiratory aerosols
• Humans are the only reservoir. Less than 100 cases/yr in US
• Virus invades respiratory tract
• Sore throat, dry cough, headache, conjunctivitis, lymphadenitis,
and fever, skin rash and oral lesions called Koplik's spots

RSV
• Also called Pneumovirus
• Infects upper respiratory tract & produces giant multi-nucleate cells
• Most prevalent cause of respiratory infection in children 6 months
or younger; most susceptible to serious disease
• Epithelia of nose & eye portal of entry
• Replicates in nasopharynx
• Rhinitis, wheezing, otitis, croup
• Treatment: Synagis, a monoclonal antibody that blocks attachment,
and ribavirin 5 out of a 1000 babies will be infected.

Rabies
-Rhabdovirus family; genus Lyssavirus
-Bullet-shaped, enveloped virions
-Slow, progressive zoonotic disease
-Virus enters through bite, grows at trauma site for a
week, enters nerve endings & advances toward the
ganglia, spinal cord & brain.
-Furious form of rabies – agitation, disorientation,
seizures, twitching, hydrophobia
-Dumb form of rabies – paralyzed, stuporous
-Often diagnosed at autopsy – intracellular inclusions
(Negri bodies) in nervous tissue
-Raccoons are the most common carriers U.S., but
bats are most likely to infect humans.
-Skunks and foxes also a carrier
-Few cases reported in wolves, coyotes, bobcats, and ferrets
-Smaller rodents (squirrels, mice, rabbits)-not a typical carrier
-10% of cases become fatal and 90% of infections are from dogs
-Vaccine can stop infection after infection has started
-Often autopsy diagnosed-intracellular inclusions & nervous tissue
-Treatment is passive and active post-exposure immunization
-Louis Pastuer made first vaccine for

Coronavirus (SARS)
A large RNA virus with distinctively spaced spikes on their envelopes. They are very common in domesticated animals. Three types or Coronaviruses have been characterized: HCV causes a cold, an enteric virus, and SARS which is transmitted air born and is 10% fatal.

Guillian Barre Syndrome
a neroligical complication that can arise in approxiamtely one in 10,000 vaccine recipients.
syndrome appears to autoimmunity induced by viral proteins and marked by varying degress of demyelenation of the peripheral nervous system, leading to weakness and sesnsory loss.
most patients recover function, but the disease can also be debilitating and fatal

Rubella (German Measles)
• Caused by Rubivirus,a Togavirus
• ssRNA with a loose envelop
• Teratogenic effects- cataracts, other congenital defects
• Transmitted through contact with respiratory secretions
• Postnatal rubella – malaise, fever, sore throat, lymphadenopathy, rash, generally mild
• Congenital rubella – infection during 1st trimester most likely to induce miscarriage or multiple defects such as cardiac abnormalities, ocular lesions, deafness, mental & physical retardation
• Attenuated viral vaccine MMR

Arboviruses
Since vertebrates are hosts to more than 400 viruses tranmitted primarily by arthropods, they are often lumped together in a loose grouping called the arboviruses (arthropod-borne viruses).
Epidemiology
Because arthropod vectors (mosquitoes, ticks, flies & gnats) are found worldwide, so too are the arboviruses they carry. Prevalence tends to be in the tropics and subtropics, but they are also prevalent in wilderness areas. All aspects of the arbovirus life cycle are closely tied to the ecology of the vectors. Factors that weigh most heavily are the arthropod's life span, the availability of food and breeding sites, and climatic influences such as temperature and humidity. Most arthropod vectors become infected by feeding on the blood of hosts. Infections show a peak incidence from late spring through early fall, when the arthropod is actively feeding and reproducing. Warm-blooded vertebrates also maintain the virus during the cold and dry seasons. Humans can serve as dead-end accidental hosts or they can be a maintenance reservoir.
Arboviral diseases have a great impact on humans. Although exact statistics are unavailable, there is a consensus that millions of people acquire infections each year and thousands of them die. The uncertain nature of vector and viral cycles frequently results in sudden, unexpected epidemics, sometimes with previously unreported viruses. Travelers and military personnel entering endemic areas are at special risk because, unlike the natives of that reigion, they have no immunity to the viruses.

• First signs of AIDS are opportunistic infections such as Pneumocystis Carinii Pneumonia (PCP) and cancers such as aposi sarcoma
• HIV attaches to CD4 & a co-receptor, XCR4
• HIV fuses with cell membrane; reverse transcriptase makes a DNA copy of RNA
• Viral DNA is integrated into host chromosome (provirus)
• Can produce a lytic infection or remain latent

Tested with a simple blood test. It can be tested with the regular blood test that may take several days to a week. It can also be tested with a rapid H.I.V. test, which is more beneficial for persons who may have recently been exposed to blood. The rapid test is more beneficial, because if H.I.V. is detected, anti-viral medications can be administered after the rapid test is finished (only four hours).

Questions:	Q&A~~Home Page~~Top of Page

Progression of HIV disease
• Initial infection – mononucleosis-like symptoms that soon disappear
• Asymptomatic phase 2-15 years
• Antibodies are detectable 8-16 weeks after infection
• HIV destroys the immune system
• When T4 cell levels fall below 200/μL symptoms appear including fever, swollen lymph nodes, diarrhea, weight loss, neurological symptoms, opportunistic infections & cancers
• Treatments, inhibit viral enzymes: reverse transcriptase, protease,
• Integrase, inhibit fusion, inhibit viral translation
• No vaccine
• Prevention, monogamous sexual relationships, condoms,and universal precautions

AIDS
• First emerged in early 1980s
• HIV-1 & HIV-2 are not closely related
• HIV-1 may have originated from a chimpanzee virus
• 1959 first documented case of AIDS • HIV is found in blood, semen, & vaginal secretions.
• HIV is transmitted by sex, sharing needles, and mother to child.
• HIV does not survive long outside of the body.

Risk Factors for AIDS
-Homosexuals or bisexual males- 45%
-Intravenous drug users- 30%
-Heterosexual partners of HIV carriers-11%
-Unapparent or unknown risk-9%
-Blood transfusions are no longer a serious risk due to testing
-Congenital or neonatal- can be reduced with antiviral drugs
-Medical and dental personnel- 1/500 needle-stick

Poliomyelitis (Polio)
-Acute enteroviral infection of the spinal cord that can cause neuromuscular paralysis
-It is also called the infantile paralysis because it often affects small children
-Has a naked capsid that confers chemical stability and resistance to acid, bile, and detergents
-Virus survives gastric environment and other harsh conditions, which contributes to its ease in transmission
-Is more pronounced during the summer and fall
-Is passed within the population through food, water, hands, objects contaminated with feces, and mechanical vectors.

Diagnosis of Polio
Polio is mainly suspected when epidemics of neuromuscular disease occur in the summer in temperature climates. It can usually be isolated by inoculating cell cultures with stool or throat washings during early part of the disease. The stage of the patients infection can also be demonstrated by testing serum samples for the type and amount of antibody.

Treatment and Prevention of Polio
The mainstay of prevention is vaccination as early in life as possible, usually in 4 doses starting at about 2 months old. Adult candidates for immunization would be travelers and members of the army.
There are 2 forms of the vaccine currently in use, the inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV). Both are prepared from animal cell cultures, are trivalent and are effective.

THIS IS A LITTLE BIT MORE COMPACT VERSION OF WHAT WE NEED TO KNOW FOR CH 25 RNA VIRUSES

-False negative vs. false positive - try to minimize false negatives
-Phenylketonuria (PKU) - test babies for enzyme and if they can metabolize it
-Influenza
.....-enveloped
.....-antigens (spikes) change
..........-drift - minor
..........-shift - major
.....-harvard has a library of antibodies and one works well against the base of flu spikes rather that the tip of spikes
.....-w/in top 10 causes of death world wide
.....-respiratory transmission
.....-infect all sorts of things and can jump to different hosts ie. humans and bird flu
.....-fever, headache, throat pain, but NOT VOMITING
.....-classified by numbers
.....-becomes more and more resistant each year
.....-post war 1918-1919 20-40 million deaths
.....-25 times more leathal than normal
.....-10 times more deadly than the war was
-bird flu
.....-very close proximity to birds
.....-person to person, but never person to person to person
-Mumps
.....-uncommon
.....-German measles (Reubella)
..........-could cause birth defects
.....-regular measles
..........-white spots inside mouth
-Rabies
.....-enveloped
.....-effects brain and changes behavior
.....-don't want water
.....-can still get antibodies after infection
..........-only one like that
.....-most common in dogs
..........-look for dark inclusions in brain/spinal cord
-Retrovirus
.....-HIV
..........-comes in as RNA and goes to DNA and then inserts in to our DNA
.....-AIDS
..........-less than 200 T-cells per MM of blood
..........-attacks T-helper cells and macrophages
..........-destroys immune system and other illness kill you
-Polio
.....-fecal/oral - intestinal
.....-usually doesn't infect nervous system
.....-most people had it in the 1950's
-Hepatitis
.....-A and C - RNA
.....-B - DNA

Questions: Q&A~~Home Page~~Top of Page

1. Which receptors of the influenza virus are responsible for binding to the host cell?
a. hemagglutinin
b. neuraminidase
c. type A
d. capsid proteins

2. The primary site of attack in influenza is the
a. small intestine
b. respiratory epithelium
c. skin
d. meninges

3. Which of these happens in the case of antigenic shift in influenza A?
a. single mutations in hemagglutinin
b. recombination of RNA segments between bird and human strains
c. change from influenza A to influenza B
d. both a and b

4. Infections with ______ virus cause the development of multi-nucleate giant cells.
a. rabies
b. influenza
c. pneumo
d. corona

5. Which virus is responsible for Korean hemorrhagic fever?
a. Ebola virus
b. hantavirus
c. arena virus
d. flavivirus

6. For which disease is an exanthem (skin rash) not a symptom?
a. measles
b. rubella
c. coxsackievirus infection
d. parainfluenza

7. A common, highly diagnostic sign of measles is
a. viremia
b. red rash
c. sore throat
d. Koplik's spots

8. Viruses that cause serious diseases in infants are ____ and _____.
a. mumps, calicivirus
b. respiratory syncytial virus, rotavirus
c. coxsackievirus, HTLV II
d. bunyavirus, cardiovirus

9. Rabies virus has an average incubation period of
a. 2 to 3 weeks
b. 1 to 2 years
c. 4 to 5 days
d. 1 to 2 months

10. For which disease are active and passive immunizations given simultaneously.
a. influenza
b. yellow fever
c. measles
d. rabies

11. Which of the following is considered to be the next pandemic?
a. mumps
b. avian influenza
c. measles
d. west Nile virus

12. Measles and the German measles are caused by the same virus Morbillivirus?
a. True
b. False

13. Which of the following is considered dangerous for infants and hospitals try to prevent?
a. Pneumonvirus
b. Morbillivirus
c. mumps

14. Which of the following has bullet-shaped virions?
a. RSV
b. Mumps
c. Influenza
d. Rabies

15. This animal is the most common carrier of rabies in the US...
a. dogs
b. skunks
c. foxes
d. raccoons

16. Polio and hepatitis A viruses are _______ viruses.
a. arbo
b. enteric
c. cold
d. syncytial

17. Which of the following cells is a target of HIV infection?
a. dendritic cells
b. monocytes
c. helper T cells
d. all of these can support infection

DNA Viruses

flattail — Tue, 23 Jun 2009 16:20:39 CDT

Introduction to Viruses that Infect Humans:

The DNA Viruses

Naming viruses
-No taxa above Family (no kingdom, phylum)
-19 families of animal viruses
-Family name ends in viridae
-Genus name ends in virus

Capsids
All viruses have a protein coat called a capsid that encloses and protects the nucleic acid. A capsid is constructed from identical subunits called capsomers, which are made of protein. There are two types of capsids: Helical and icosohedral.

Host Range
A cell has to have a specific structure or receptor on its surface for a virus to be able to attach to it. A cell has to contain all of the enzymes and materials needed to produce new variations. It can be for one species or for many different ones. Most are specific and infect just humans, dogs, and plants.
The difference between Phage and animal virus replication:
1. Animal virus replication is MORE complex than phage replication because host cells are more complex
2. Animal Viruses cannot inject their DNA
3. Lysogeny for phage, latency for animal viruses

Animal Virus Replication
1. Absorption
2. Penetraion/ uncoating of genome
3. Duplication/synthesis
4. Assembly
5. Release

Ways Cells Are Damaged By Viruses
-changes in size and shape
-cytoplasmic inclusion bodies
-nuclear inclusion bodies
-cells fuse to form multi-nucleated cells
-cell lysis
-alter DNA
-transform cells into cancerous cells

Cell Lysis Multinucleated Cell Cancerous Cell

Viruses
Are obligate parasites that infect animals, plants, and other microbes. Viruses are limited to a particular host or cell type. Most DNA viruses bud off of the nucleus and most RNA viruses multiply and are released from the cytoplasm. Viral infections can range from very mild similar to a cold, to life threatening like HIV. Several viruses are able to cross the placenta and cause developmental disturbances. The term teratogenic is used for the cross infection from mother to the embryo or fetus. A virus can become a permanent resident of the host cell and just stay latent at times. Some cell changes from virus infections are visible to the naked eye ex: inclusion bodies seen from Rabies victims.The first known virus, tobacco mosaic virus, was discovered by Martinus Beijerinck in 1898, and now more than 5,000 types of virus have been described.The study of viruses is known as virology, and is a branch of microbiology.

POXVIRUSES
-produce eruptive skin pustules called pocks or pox that leave scars
-largest and most complex animal viruses
-have the largest genome of all viruses and multiply in the cytoplasm in well defined sites called factory areas which appear as inclusion bodies infected cells.
-multiply in cytoplasm in factory areas
-they are an enveloped DNA virus
-Variola - cause of smallpox
- Vaccinia - (agent of cowpox) closely related virus used in vaccines
- Monkeypox
- Cowpox
-Molluscipox

Smallpox (Variola)

-first disease to be eliminated by a live vaccination (due to Edward Jenner)
-exposure through inhalation (respiratory route) or skin (scabs) contact
-infection associated with fever, malaise, prostration and rash
-Variola major - highly virulent-caused toxemia, shock and intravascular coagulation(20-40% mortality)
-Variola minor - less virulent (1% mortality) milder symptoms and a lower death rate.
-killed majority of some tribes of Native Americans, and people of Hawaii.
-routine vaccination ended in US in 1972
-the last naturally occuring case of smallpox occured in 1977
-vaccine was reintroduced in 2002 because of possible bioterrorism. Mainly inlisted officers/military receive the vaccine when traveling overseas
-Infection includes fever, malaise, prostration. Later a rash begins in the pharynx, spreads to the face, and progresses to the extremities.
-Smallpox caused 300-500 million deaths during the 1900's. As recently as 1967, 2 million people died from smallpox. WHO declared smallpox to be eradicated in 1979.
The CDC and its equivalent in Russia each kept samples of the virus. Threat of bioterrorism has brought the vaccine back.

Q: Which statement regarding the poxviruses is incorrect?
a. They multiply in the cytoplasm.
b. They are non-enveloped DNA viruses.
c. Their sites of multiplication within infected cells appear as inclusion bodies.
A: They are non-enveloped DNA viruses

Q: Which is the causative agent of smallpox?
a. Vaccinia virus
b. Monkeypox virus
c. Variola virus
A: Variola virus

Here is Dr. Larry Brilliant telling the fascinating tale of the eradication of smallpox:

Diagnosing Infections

flattail — Tue, 23 Jun 2009 16:19:41 CDT

Chapter Overview

The ability to identify microbes that are responsible for a patients symptoms is central to infectious disease microbiology. Diagnosis might be considered an art and a science, involving multiple health care providers and clinical personnel.

In order to successfully identify an infectious agent, the specimen containing that agent must be properly collected, handled, and stored.
1. Accurate diagnosis depends on the ability to differentiate the causative organism from normal flora or contaminating microbes.
Most diagnostic tests fall into two categories: presumptive data, which place the microbe in a preliminary category, and more specific data which provide definitive evidence of a species.
1. G+C relative to A+T can place a microbe in a preliminary category, but specific DNA sequences could identify it to a species level.
Microbiologists use phenotypic, immunological and genotypic techniques to identify bacteria.

Phenotypic identification methods assess a microbe's appearance, growth characteristics, and/or chemicals and enzymes.
Most lab tests are phenotypic identification methods. Usually several tests need to be done in a sequence before identification can be made. A "dichotomous key" of "flowchart" guides the testing.
Specimens are often inoculated into differential and selective media to define characteristics such as fermentation patterns and reactions (lysis) in blood.
Microscopic observation of specimens is a rapid method to determine preliminary characteristics of a microbe.

DNA sequences that are unique to an organism can be used to “probe” for that organism.
1. PCR is often used to amplify DNA present in samples.
2. PCR depends on DNA polymerase from hot springs bacteria Thermophilus aquaticus (Taq polymerase)
3. Here are two videos: one with a good explanation of how PCR works, and the second is a corny song of scientists singing about how great PCR is ("PCR, when you need to find out who your daddy is...").
Serology deals with in-vitro diagnostic testing of serum, has a high degree of specificity and sensitivity, and is based on the specificity an antibody has for its antigen.
1. Agglutination testing is based on the cross-linking of antigens and antibodies to form visible clumps
2. Precipitation reactions involve the precipitation of a soluble antigen by an antibody.
3. Western blot analysis uses antibodies to identify specific proteins that have been transferred onto a filter.
4. Complement fixation tests can be used to determine the presence of specific antigen-antibody complexes.
5. Monoclonal antibodies can be labeled with a fluorescent dye and used to detect a specific antigen in a solution or used to react with an Fc portion of another antigen.
6. The ELISA involves the interaction of antibodies and antigens and can be used to determine an unknown antibody (indirect) or antigen (direct or capture).

Tests by Type

Microbiologists use three categories of techniques to diagnose infections: phenotypic, genotypic, and immunological.

Phenotypic Tests	Immunological Tests	Genotypic Tests
Direct examination of specimen -Gram stain -Acid-fsat stain -DFA (Direct Fluorescence Antibody) -Direct antigen testing (rapid testing)	Agglutination Testing -Widal test -Latex agglutination	Nucleic acid sequencing and rRNA analysis
Biochemical testing -Carbohydrate fermentation -Hydrolysis of gelatin, starch -Enzyme actions (catalase, oxidase, coagulase) -Byproducts of metabolism	Precipitation testing	Polymerase chain reaction
Phage typing	Western Blot	G+C base composition
Animal inoculation	Compliment fixation
Antimicrobial sensitivity	Toxin neutralization -Treponema pallidum immobilization (TPI) -Quellung
	Fluorescent antibodies/immunofluorescent testing -Direct vs. indirect
	Immunoassays -Radioimmunoassay (RIA) -Enzyme-Linked Immunosorbent Assay (ELISA)
	T cell and B cell differentiation testing
	In vivo testing -Tuberculin test

Phenotypic Methods
The main phenotypic methods include the direct examination of specimens, observing the growth of specimen cultures on special media, and biochemical testing of specimen cultures.
Microscopic Morphyology-Traits that can be valuable aids to identification of cell shape and size, Gram-stain reaction, acid-fast reaction and special structures, including endospores, granules, and capsules. Electron microscopes can pinpoint additional features such as: cell wall flagella, pili, and fimbriae.

Macroscopic Morphology-Traits that can be assessed with the naked eye are also useful in diagnosis. These include the appearance of colonies, including texture, shape, size, pigment, speed of growth, and patterns of growth in broth and gelatin.

Physiological/Biochemical Characteristics-Bacterial identification: Enzymes and other biochemical properties of bacteria are reliable and stable expressions of the chemical identity of each species.Diagnostic tests exist for determining the presences of specific enzymes and to assess nutritional and metabolic activities. Test examples: fermentation of sugars, capacity to digest or metabolize complex polymers such as proteins and ploysaccharides; production of gas; presence of enzymes such as catalase, oxidase, and decarboxylase; and sensitivity to antimicrobic drugs.

Chemical Analysis-This involves analyzing the types of specific structural substances that the microorganism contains, such as the chemical composition of peptides in the cell wall and lipids in the membrane.

Genotypic Methods-Identifying and classifying bacteria. There are many advantages of genotypic methods over phenotypic methods, when they are available. The primary advantage is that actually culturing the microorganisms is not always necessary. There are many microorganisms we can't grow in the lab, compared to how many we can. Another advantage is that genotypic methods are increasingly automated, and results are obtained very quickly, often with more precision than with phenotypic methods.

Immunological Methods-bacteria and other microbes have surface and other molecules called antigens that are recognized by the immune system.On immune response to antigens is the production of molecule called antibodies that are designed to bind tightly to the antigens.The nature of antibody response can be determined from blood or other tissue samples. The presence of specific antibodies to a suspected pathogen is highly suggestive of infection.This is an easy test for microbes, especially in the case of viral infections. (Example: HIV testing). Laboratory kits immediately identify the number of pathogens.

Specimen Collection
In sites that normally contain resident microflora, care should be taken to sample only the infected site and not the surrounding areas. For example, throat and nasopharyngeal swabs should not touch the tongue, cheek or saliva. Saliva is an especially undesirable contaminant because it contains millions of bacteria, of which are normal flora. Sputum, the mucous secretion that coats the lower respiratory surfaces, especially the lungs, is discharged by coughing or taken by a catheterization to avoid contamination with saliva.
Also the mucous lining of the vagina, cervix, or urethra can be sampled with a swabbed or applicator stick.
Additional sources of specimens are the vagina, eye, ear canal,nasal cavity (all by swab), and diseased tissue that has been surgically removed (biopsied).

Urine is taken aseptically from the bladder with a catheter. Another method is called a "clean catch" is taken by washing the external urethra and collecting the urine in midstream. Some diagnostic techniques require first-voided "dirty catch" urine.

Sterile materials such as blood. cerebrosspinal fluid, and tissue fluid must be taken by sterile needle aspiration.

Overview of Laboratory Techniques
1.Direct testing using a microscope, immunological, or genetic methods that provide immediate clues as to the identity of the microbe or microbes in sample and 2. cultivation, isolation, and identification of pathogens using a wide variety of general and specific tests (such as blood or other fluids).

Most tests fall into two categories:presumptive data, which place the isolated microbe in a preliminary category such as genus, and more specific, confirmatory data, which provide more definitive evidence of a species.

Some diseases are diagnosed with out the need to identify microbes from specimens. Serological tests on a patients serum can detect signs of an antibody response. One method that clarifies whether a positive test indicates current or prior infection is to take two samples several days apart and see if the antibody titer is raising. Skin testing can pinpoint a delayed allergic reaction to a microorganism. These tests are important in screening the general population for exposure to an infectious agent such as rubella or tuberculosis.

Immediate Direct Examination of Specimens
Direct microscope observation of a fresh or stained specimen is one of the most rapid methods of determining characteristics. Stains most often employed for bacteria are the gram stain, they do not work on some organisms though. Direct florescence antibody (DFA) test can highlight the presence of the microbe in patient specimens by means of labeled antibodies. This test is useful for bacteria such as syphilis spirochete, that are not readily cultivated in a laboratory or if rapid diagnosis is essential for the survival of a patient.

Isolation Media
In most cases, specimens are also inoculated into differential media that define such characteristics as reactions in blood(blood agar) and fermentation patters (mannitol salt and MacConkey agar. A patients blood is usually cultured in a special bottle of broth that can be periodically sampled for growth. Work must be done from isolated colonies or pure cultures, working with mixed or contaminated cultures give misleading and inaccurate results.From such isolates, clinical microbiologist obtain information about a pathogen's microscopic morphology and staining reactions, culture appearance, motility, oxygen requirements, and biochemical characteristics.

General Guidelines	For Specimen	Collection
Type of Specimen	Collection Method	Comments
Abcess of skin or membrane or decubitus ulcer	Debride surface with sterile wipe; suction fluid with sterile needle and syringe	Aspiration of tissue samples preferred to swab; transfer to anaerobic transport system.
Anaerobic cultures	Collect from deeper tissue below the surface, using sterile syringe	Sample must not be exposed to air; transported immediately in anaerobic system to lab
Blood	prep area of skin eith iodine; use vacutainer blood collection tubes	Inoculate blood culture bottle immediately
Bone marrow	Prepare site for surgical incisiton; extract sample with special needle.	Most samples are taken from sternum or ilium; placed in blood bottle for culture
Cerebrospinal fluid (CSF)	Remove CSF aseptically by lumbar puncture	Place CSF into sterile tubes; do not refigerate; transport immediatiely to lab for processing
Feces	Take a small specimen into sterile container, cover, and transport	Refrigerate samples held over one hour; culture is mainly to rule out enteric pathogens; special kits available to detect systs and trophozoites of protozoans and ova and larvae of intestinal worms
Genital/urinary tract	Sterile swab of cervical mucus; swab urethral membrane or insert into lumen and twist.	Plate directly onto selective culture media with high CO2 atmosphere; or collect wiht anaerobic transport swab system; process immediately.
Respiratory tract, lower	Have patient cough to loosen phlegm and expectorate sputum into sterile cup for transport	Patient should brush teeth and rinse mouth with water prior to any sampling. If coughing does not work, induce sputumby having patient inhale sterile saline from a nebulizer.
Urine	Sampling is usually done with sterile catheter or by clean midstream cath into a sterile container.	Patient must wash hands and clean external genitalia, separate labia (female) or pull back foreskin (male) and urinate for a short time; followed by collection of 100-200 cc sample (midstream); samples not immediately processed must be refigerated.
	Catheter must be sterile and inserted into bladder; urine is drainded into sterile container	Clean and rinse the urethral opening; only a specimen catheter should be used ot sample for bladder infection; patients wiht indwelling catheters will always have microbes in their bladders.

Questions: Q&A~~Home Page~~Top of Page

1. Which of the following methods is most sensitive for identifying different strains of a microbe?
a. microscopic examination
b. radioimmunoassay
c. DNA typing
d. agglutination test

2. In agglutination reactions, the antigen is a ______; in precipitation reactions, it is a ________.
a. soluble molecule, whole cell
b. whole cell, soluble molecule
c. bacterium, virus
d. protein, carbohydrate

3. Which reaction requires complement?
a. hemagglutination
b. precipitation
c. hemolysis
d. toxin neutralization

4. A patient with a _______ titer of antibodies to an infectious agent generally has greater protection than a patient with a ________ titer.
a. high, low
b. low, high
c. negative, positive
d. old, new

5. Direct immunofluorescence tests use a labeled antibody to identify _____.
a. an unknown microbe
b. an unknown antibody
c. fixed complement
d. agglutinated antigens

6. The Western blot test can be used to identify
a. unknown antibodies
b. unknown antigens
c. specific DNA
d. both a and b

7. An example of an in vivo serological test is
a. indirect immunofluorescence
b. radioimmunoassay
c. tuberculin test
d. complement fixation

Definitions

Phenotypic: The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences.
Genotypic: the genetic constitution of an individual, that is the specific allele makeup of the individual, usually with reference to a specific character under consideration
Probes: Mechanical devices equipped with sensors that enable us to gather information without direct human contact.
Serology: The branch of science dealing with the measurement and characterization of antibodies and other immunological substances in body fluids, particularly serum.
Widal Test: the Widal test is a presumptive serological test for Enteric fever or Undulant fever.
Titer: A measurement of the amount of antibodies in the blood
Lysin: any substance (such as an antibody) or agent that can cause lysis
Complement Fixation: an immune response in which an antigen-antibody combination inactivates a complement
Treponema pallidum immobilization (TPI): A test for syphilis in which an antibody other than Wassermann antibody is present in the serum of a syphilitic patient; in the presence of complement, the patients serum causes the immobilization of actively motile Treponema pallidum obtained from testes of a rabbit infected with syphilis. Also called TPI test.
Immunoassays: Are extremely sensitive alternative methods that permit rapid and accurate measurements of trace antigen or antibody.

Your Specific Defenses

flattail — Tue, 23 Jun 2009 16:18:47 CDT

Adaptive,Specific Immunity and Immunization

Production of specific antibodies by dual system of B and T lymphocytes in response to an encounter with a foreign molecule, called an antigen.
Antigen- any foreign molecule, they tend to be big and complex. The are molecules on the surface of a bacteria or a virus.

Primary and Secondary Response to Antigens
Primary Response- after first exposure to an Ag immune system produces IgM and a gradual increase in Ab titer(concentration of antibodies) with the production of IgG.
Secondary Response- after a second contact with the same Ag, immune system produces a more rapid, stronger response due to memory cells- anamnestic response.

Monoclonal Antibodies
-Pure preparation of antibody
-Single specificity antibodies formed by fusing a mouse B cell with a cancer cell.
-Used in diagnosis of disease, identification of microbes and therapy.

Two features that characterize specific immunity:
Specificity- antibodies produced, function only against the antigen that they were produced in response to
Memory- Lymphocytes are programmed to "recall" their first encounter with an antigen and respond rapidly to subsequent encounters

Classifying Acquired Immunities:

1. Blood with antibodies is taken from humans or animals who have had the infection recently.

2. Blood serum containing antibodies is separated from the blood, processed, and injected.

3. Antibodies either attack a current infection or provide short-term protection.

Q: Which of the following is an example of artificial passive immunity?
a. A person who recovers from an infectious disease
b. A person who receives immune serum during treatment for hepatitis
c. A newborn receiving antibodies in breast milk while breast feeding
A: A person who receives immune serum during treatment for hepatitis

Here are a couple videos that may help explain the connections between macrophages, helper T-cells, and B-cells.
Hope they help!

Definitions

Alloantigens- cell surface markers of one individual that are antigens to another of that same species.
Superantigens- potent T cell stimulator's; provoke an overwhelming response.
Allergen- antigen that provokes allergy.
Autoantigens- molecules on self tissues for which tolerance is inadequate.
Natural immunity- acquired as part of normal life biological experiences
Artificial immunity-acquired through a medical procedure such as a vaccine
Natural active immunity- acquired upon infection and recovery
Natural passive immunity- acquired by a child through placenta and breast milk
Artificial active immunity-acquired through inoculation with a selected Ag
Artificial passive immunity-administration of immune serum or vaccine (antibodies) from human or animal donor
Active immunity- results when a person is challenged with antigen that stimulates production of antibodies; Creates memory, takes time and is lasting
Passive immunity- preformed antibodies are donated to an individual; does not create memory, acts immediately, and is short term.

Your General Defenses

flattail — Tue, 23 Jun 2009 16:17:57 CDT

Host Defenses: The Immune System
Learning Objectives

1. Learn about and describe the interconnecting network of host protection against microbial invasion

a. What generally constitutes the first line of defense
b. What generally constitutes the second line of defense
c. What generally constitutes the third line of defense

2. Define the immune system

a. Name the 4 major subdivisions of this system
i. Define the RES or reticuloendothelial system and the role it plays in immunity
ii. Define the ECF or extracellular fluid and the role it plays in immunity
iii. Describe the role the blood vascular system plays in immunity
1. Describe the differences between the specific and non-specific defenses of the blood
a. Define the two components of the specific immune response and the role they play in immunity
iv. Describe the three function of the lymphatic system in regard to host immunity
2. Name some important sites in the body with lymphoid tissues

3. Learn about and be able to describe the actions of the second line of defense
a. Define Toll-like receptors and the role they play in activating the immune response

b. Define and describe the four symptoms of inflammation
c. Define the role of fever in the immune response

i. What causes fever ii. How does it help protect the body

d. Define Macrophages and Neutrophils (PMN’s), and their role in the body’s immune response
e. Define complement and explain its role in the body’s immune response

We can’t see them. Nevertheless, millions of them are everywhere around us, clinging to us, bent on getting inside of us. If unstopped, they would soon take us over completely.

With life’s beginning, the virus and bacteria wars begin, and they will not end until the last breath is drawn. For months before birth, the fetus is gearing up for battle, producing weapons for the immune system.

“By the age of two or three months, ... weapon manufacturers in the red bone marrow and thymus are working flat out. When the child is ten years old, the human immune system is at its strongest, armed to the teeth. Thereafter, its powers gradually deteriorate.”–The Body Victorious, pages 34-5.

Therefore, our response to viral and bacterial infections, and their destructive ability, is war. It is total war between these disease-carrying alien invaders and our body’s immune system. No quarter asked, none given. Our lives hang in the balance, it is them or us. Usually we win, but not always. The outcome depends on how quickly our immune system is stimulated for the fight.

The immune system is one of the most incredible and complex features of our amazing bodies. The immune system has an incredible ability for dealing with information, for learning and memory, and for creating, storing and using information. It recognizes molecules that have never been in the body before and can differentiate between what belongs there and what doesn’t.

The immune system, which is made up of special cells, proteins, tissues, and organs, defends people against germs and microorganisms every day. In most cases, the immune system does a great job of keeping people healthy and preventing infections. But sometimes problems with the immune system can lead to illness and infection.

The primary functions of a healthy functioning immune system can be summerized as:
1. Surveillance of the body
2. Recognition of foreign material such as pathogens
3. Attack and destrution of foreign invaders

White blood cells formed in the bone marrow are responsible for most of the reactions of the immune system, including antibody production, phagocytosis, and many aspects of inflammation. Lymphoid organs such as the spleen, lymph nodes, and thymus are also intimately involved in these defense mechanisms. Cells of the immune system are able to travel freely among different areas of the body because of the interrelationship between the blood, the lymphatic system, and the reticuloendothelial system. Communication between cells of the immune system is facilitated by the release of chemical messengers such as cytokines. These chemicals stimulate a variety of beneficial responses: They increase blood flow and the migration of white blood cells; they initiate fever; or they destroy virally infected cells. The inflammatory response is a complex reaction to infection that works to fight foreign agents and limit further damage to the body. White blood cells known as phagocytes help to clear foreign organisms from the body. The complement system acts to lyse cells that have been identified as foreign.

Defense Mechanisms of our body

Line of Defense	Innate / Acquired	Specific or Nonspecific	Development of Immunological Memory	Examples
First	Innate	Nonspecific	No	Physical barriers: skin, tears, coughing, sneezing Chemical barriers: low pH, lysozyme, digestive enzymes Genetic barriers: resistance inherent in genetic makeup of host (pathogen cannot invade).
Second	Innate	Nonspecific	No	Phagocytosis, inflammation, fever, interferon
Third	Acquired	Specific	Yes	T lymphocytes, B lymphocytes, antibodies

So what is the first line of defense?

In actuality there are several types of barriers that protect organisms from infection, including mechanical, chemical and biol ogical barriers. The immune system consists of three overlapping lines of defense, the first two of which provide nonspecific protection against anything seen as being foreign to the body. The first line of defense consists of barriers to foreign objects, while the second is responsible for protecting the body once foreign matter has entered. The third is more unique and is in relation to how the genetic makeup of an individual predisposes that individual to be more vulnerable to some pathogens and immune to others.

Physical Barriers of an Organisms Body
The waxy cuticle of many leaves, the exoskeleton of insects, the shells and membranes of externally deposited eggs, and skin are examples of the mechanical barriers that are the first line of defense against infection. However, as organisms cannot be completely sealed against their environments, other systems act to protect body openings such as the lungs, intestines, and the genitourinary tract. In the lungs, coughing and sneezing mechanically eject pathogens and other irritants from the respiratory tract. The flushing action of tears and urine, also mechanically expels pathogens, while mucus secreted by the respiratory and gastrointestinal tract serves to trap and entangle microorganisms.

Chemical Defenses
Chemical barriers also protect against infection. The skin and respiratory tract secrete antimi crobial peptides such as the β defensins. Enzymes such as lysozome and phospholipase A2 in saliva, tears, and breast milk are also antibacterials. Vaginal secretions serve as a chemical barrier following menarche, when they become slightly acidic, while semen contains defensins and zinc to kill pathogens. In the stomach, gastric acid and proteases serve as powerful chemical defenses against ingested pathogens.
Within the genitourinary and gastrointestinal tracts, commensal flora serve as biological barriers by competing with pathogenic bacteria for food and space and, in some cases, by changing the conditions in their environment, such as pH or available iron. This reduces the probability that pathogens will be able to reach sufficient numbers to cause illness. However, since most antibiotics non-specifically target bacteria and do not affect fungi, oral antibiotics can lead to an “overgrowth” of fungi and cause conditions such as a vaginal candidiasi (a yeast infection). There is good evidence that re-introduction of probiotic flora, such as pure cultures of the lactobacilli normally found in unpasteurized yogurt, helps restore a healthy balance of microbial populations in intestinal infections in children and encouraging preliminary data in studies on bacterial gastroenteritis, inflammatory bowel diseases, urinary tract infection and post-surgical infections.

Genetic Defenses
Some pathogens have such specificity that the genetic makeup of a person could be enough to make them immune to those pathogens. Viruses are an excellent example as they attach themselves to a specific host receptor, if the host doesn't have the receptor the virus needs, then there is nothing to attach too and thus is not infected. Another example of a genetic defense is an individual that carries the gene for sickle-cell anemia are resistant to aquiring malaira. This also holds true for susceptibility to tuberculosis, leprosy, and some systemic fungal infections, if the individual has a gene that provides a resistance to them.

Test yourself: What is the first line of defense? What are examples of it? Is it innate or acquired? Nonspecific or specific? Why is the skin considered a defense against microbes? What are some examples of physical or anatomical barriers at the body’s surface? How does the ciliary escalator guard the respiratory tract against microorganisms? What are the nonspecific chemical defenses of the skin and eyes? What is the chemical defense found in tears and saliva, and how does it protect against bacteria? What do skin cells secrete that acts as an antimicrobe? How does this chemical work? How are the stomach, intestines, semen, and vagina inhibitory to pathogens?

The Second Line of Defense.
Organisms that manage to penetrate the body's first line of defense then encounter another hurdle: the body's nonspecific immune system. The term nonspecific means that this line of defense goes into operation whenever any kind of foreign material enters the body. The immune systems of animals have developed the ability to tell the difference between its own cells, that is, cells produced by the body, and any other kind of material. The foreign matter might be another kind of organism, such as a bacterium or virus; cells from another animal; or inanimate matter, such as coal dust, pollen, cigarette smoke, or asbestosis fibers. Anything that causes an immune response in an animal is said to be an antigen.
Identification of foreign particles as "not-me" cells is made by a group of white blood cells known lymphocytes. Lymphocytes search out antigens in the bloodstream and destroy them by phagocytosis. Phagocytosis is the process by which one cell surrounds a second cell and engulfs it. Once the foreign cell has been swallowed up by the lymphocyte, it is digested by enzymes released from the lymphocyte.
The invasion of antigens can also produce an inflammatory response. Suppose you cut your finger on a tin can. The cut soon becomes red, swollen, and warm. These sign s are evidence of the inflammatory response. Injured tissues send out signals to immune system cells, which quickly migrate to the injured area. These immune cells perform different functions. Some destroy bacteria by phagocytosis. Others release enzymes that kill the bacteria. Still other cells release a substance called histamine. Histamine causes blood vessels to dilate (become wider), thus increasing blood flow to the area. All of these activities promote healing in the injured tissue.
Allergic reactions are examples of an inappropriate inflammatory response. When a person is allergic to pollen, the body's immune system is reacting to pollen (a harmless substance) as if it were a bacterium and an immune response is prompted. When pollen is inhaled, it stimulates an inflammatory response in the nasal cavity and sinuses. Histamine is released, which dilates blood vessels and causes large amounts of mucous to be produced, leading to a "runny nose." In addition, histamine stimulates the release of tears and is responsible for the watery eyes and nasal congestion typical of allergies.
To combat these reactions, many people take drugs that deactivate histamine. These drugs, called antihistamines, are available over the counter and by prescription. Some allergic reactions result in the production of large amounts of histamine, which impairs breathing and necessitates prompt emergency care. People prone to these extreme allergic reactions must carry a special syringe with epinephrine (adrenalin), a drug that quickly counteracts this severe respiratory reaction.

Test yourself: What is the 2nd line of defense? What are examples of it? Is it innate or acquired? Nonspecific or specific?

Question: Why and how does an allergic reaction occurs in the nasal cavity.

A colored scanning electron micrograph of a white blood cell. (Reproduced by permission of Photo Researchers, Inc.)

The Third Line of Defense

The body's third line of defense against invasion by foreign organisms is the specific immune system. The specific immune system consists of two kinds of lymphocytes known as T lymphocytes and B lymphocytes. The two kinds of cells are sometimes known simply as T cells and B cells. Both kinds of cells are produced in bone marrow. T cells then migrate to the thymus (which gives them the T in their names), where they mature. No one knows where B cells mature. T cells and B cells differ from nonspecific lymphocytes in that they attack only very specific antigens. For example, the blood and lymph of humans have T cell lymphocytes that specifically target the chicken pox virus, T cell lymphocytes that target the diphtheria virus, and so on. When T cell lymphocytes specific for the chicken pox virus encounters a body cell infected with this virus, the T cell multiplies rapidly and destroys the invading virus.
Two kinds of T cells exist: killer T cells and helper T cells. Killer T cells go directly to the target antigen and attack it. Helper T cells have many different functions, including to help in the development of B cells. Another function is to stimulate the formation of other T cells and the release of various chemicals that aid in the destruction of antigens.

Helper T cells have an especially crucial role in the immune system. Thus, any disease that destroys helper T cells has a devastating effect on the immune system as a whole. HIV (human immunodeficiency virus, which causes AIDS [acquired immunodeficiency syndrome]), for example, infects and kills helper T cells, thus disabling the immune system and leaving the body helpless to stave off infection.

Memory cells. After an invader has been destroyed, some T cells remain behind. These cells are called memory cells. Memory cells give an animal immunity to future attacks by the original invader. Once a person has had chicken pox, memory cells are created. If the person is later exposed to the chicken pox virus again, the virus is quickly destroyed. This secondary immune response, involving memory cells, is much faster than the primary immune response.
The procedure known as vaccination makes use of the above process. Vaccination is the process by which a killed microorganism (or parts thereof) are injected into a person's bloodstream. The presence of these particles prompts the formation of memory cells without a person's having to actually develop the disease.
the third and final line of defense- acquired specific immunity is the product of a dual system the the B and T lymphocytes are composed of. During fetal development the lymphocytes undergo a selective process that specializes the for reacting only to onr specific antigen. During this time Immunocompetence, the ability of the body to react with myriad foreign substances, develops. An infant is born with the theoretical potential to acquire millions of different immunities.

B cells and the antibody response. When helper T cells recognize the presence of an invading antigen, they stimulate B cells in the blood and lymph to start reproducing. As the B cells reproduce, they also undergo a change in structure and become known as plasma cells. Those plasma cells then begin to secrete compounds known as antibodies. Antibodies are chemicals released by B cells that attach themselves to the surface of an antigen. The presence of an antibody helps other cells in the immune system recognize the antigen and mark it for destruction.

granulocytes- leukocytes which have lobed nuleus
Neutrophils- distinguished by their lobed nuclei and bu their fine, pale lavendar granules, released by bone marrow, make up 55-90% of circulating leukocytes
Eosinophils- stain orange to red granules and bilobed nucleus, more numerous in the bone marrow and the spleen, only 1-3& of the WBC count, used for the immune system sometimes, granules contain perioxidase, lysozome, and other digestive enzymes, also involved in inflammatory and allergic reactions
basophils-pale stained, constricted nuclei and very psominet dark blue to black granules. share morphologicals and functional similarities with mast cells

How to Get a Communicable Disease

flattail — Tue, 23 Jun 2009 16:17:00 CDT

Microbe--Human Interactions

How we get sick

Step one: Contact (to touch)
To come in contact with microbes. Contact does not lead to much.
typhoid mary history page
Step two: Colonization (to settle)
Does not mean you will get sick, most microbes cannot even colonize on our bodies

*The majority of the microbes that we come in contact with are considered transients which means that they are removed or destroyed by our bodies defenses long before they are able to colonize.

Step three: Infection (the spread of disease)
Microbes start living where they should not be.

Infection- condition where pathogenic microorganisms penetrate the hosts defenses, enter the tissues and multiply.

Localized Infection- microbes enter the body and remain confined to a specific tissue.

Step four: Disease (any deviation from health where tissues and organs are damaged and disrupted) -Disease-
Leads to disease.

The human body provides a favorable habitat for microorganisms which includes: *Stable temperature, *Extensive surfaces upon which to colonize, * Constant source of nurishment, and a *Relatively stable pH
Although, acids in the stomach prevent it from being colonized by most microbes

Remember
Contact usually does NOT result in an infection.
Infection usually does NOT result in a disease.
Sign- objective evidence (Fever, chest sounds, leukopenia, or tachycardia)

Symptom- subjective evidence (chills, nausea, itching, or headache) These are not measurable except by the patient.

Sequelae- long-term permanent damage to tissue or organs

Acute Infection- sudden onset; generally short-lived (flu)

Chronic Infection- persistent, continuous infection.

Q: What term is defined as any deviation from health where tissues and organs are damaged and disrupted?
a. Disease
b. Infection
c. Transient
A: Disease

Axenic = uncontaminated; germfree (FYI)

Resident flora:
• includes bacteria, fungi, protozoa, viruses andarthropods
• most areas of the body in contact with the outside environment harbor resident microbes; large intestine has the highest numbers of bacteria
• internal organs & tissues & fluids are microbe-free • bacterial flora benefit host by preventing overgrowth of harmful microbe

Sites that harbor a normal flora:

Skin and its contiguous mucous membranes

Upper respiratory tract

Gastrointestinal tract (various parts)

Outer opening of urethra

External genitalia

Vagina

External ear and canal

External eye (lids, lash follicles)

Q: What greatly influences the presence and numbers of transient flora?
a. Occupational exposure
b. Hygiene
c. Humidity
A: Hygiene

Colonization of newborns
While in the mothers womb a fetus is in a sterile environment.
After the expecting mother's water breaks the baby is exposed to vaginal microbes that enter the womb.
More comprehensive exposure occurs during the birth process as the baby while the baby comes into contact with the birth canal exposing them to streptococci, staphylococci, and lactobacilli.
Breast fed babies gain the intestinal flora of the Bifidobacterium species which metabolizes sugars into acids that protect the infant from infection.

Flora of the Skin:
The normal flora of the skin only resides in or on the dead cell layer (epidermis) or in follicles and glands.
There are two cutaneous populations of flora:

The transients (exposed flora) cling to the skin surgace but do not ordinarily grow there. These are aquired by contact and greatly influenced by hygeine.
The resident population lives and multiplies in the deep layers of the epidermis and in glands/follicles. normal skin residents consist of bacteria (staph, corynebacterium, and propionibacterium) and yeasts. Moist areas of the skin are more likely to be colonized with these bacteria.

Flora of the Mouth
The oral cavity has flora that is among the most diverse and abundant of the body. The most common residents are earobic streptococcus species :

s. sanguis, s.salviarius, and s. mitis colonize the smooth epithelial surfaces
S. mutans and s. sanguis are major dental carries and establish the basis for biofilm

Saliva has a very high bacterial count of 5x10^9 cells per mL making human bites especially dangerous. This high concentration of bacteria makes mouthwashing quite ineffective.

Flora of the Large Intestine
The Large intestine consists of the cecum and colon. The microbes located in the large intestine and rectum are so abundant that they make up 10-30% of the fecal volume.
The intestinal environment favors strictly anaerobic bacteria( bacteroides, bifidobacterium, fusobacterium, and clostridium.) And coliforms (E.Coli, Enterobacter, citrobacter) are found in smaller numbers.
The bacteria ferment waste generating vitamins and acids of potential value to host.

Flora of the Respiratory tract
Respiratory tract= nasal passages and pharynx

Oral streptococci colonize the upper respiratory tract.
Staph Aures resides in the nasal entrance, nasal vestibul, and anterior nasopharynx
Neisseria species reside in mucous membranes and behind soft palate.
Haemophilus colonize the tonsils and lower pharynx.

Flora of the Genitourinary Tract
Women: vagina and outter opening of urethra have microflora

The shortness of the urethra in women frequently causes UTI's

Men: Anterior urethra contains microflora

Internal reproductive organs are kept sterile through physical barriers.
The composition of normal flora changes with changes in physiology such as puberty.

Pathogen
Pathogen a microbe whose relationship with its host is parasitic and results in infection and diseases. True pathogens (primary pathogens) are able to cause disease in anyone whether or not they are healthy. They can be as mild as a cold or as serious as rabies. Opportunistic pathogens cause disease when the host's defense's are compromised or when they become established in a part of the body that is not natural to them. One is not known to cause disease in humans, and four is highly contagious and highly virulent. Host deficiencies are the most important cause of disease, and also the most important factors contributing to the outcome of someone who is sick.

Portal of Entry (becoming established---step 1)
The portals of entry are usually located where normal flora is. The most common sites are the skin, GI tract, respiratory tract, and the GU tract. Most pathogens have a specific portal of entry but some can enter multiple portals. Effects of the same pathogen can differ depending on which portal the pathogen enters through. The respiratory system is the portal for the largest amount of pathogens. The source of exogenous, originating from a source outside the body (the environment or another person or animal), or endogenous, already, already existing on or in the body (normal flora or latent infection)

Bacterial pathogens attach most often by the following mechanisms:
1. Fimbriae (pili)
2. Flagella
3. Capsules
4. Adhesive slimes

Portals of exit
• Respiratory, saliva
• Skin scales
• Fecal exit
• Urogenital tract
• Removal of blood

Infectious agents that enter the skin
Any break in the skin is big enough to let bacteria through to cause boils, impetigo, tetanus, and a number of other infections. Entry into the skin could be caused by mosquito bites or ticks, which are vectors. Some microbes are able to enter through sweat glands and also hair follicles. When microbes enter through a route other than the digestive tract it is called the parenteral route. These include injections, bites, wounds, cuts, and surgical sites.

Gastrointestinal Portal
The GI tract is a portal for pathogens that are contained in food, drink and other ingested subtances.
These pathogens are adapted to survive digestive enzymes and extreme pH.
Although the Anus is not normally a portal of entry in becomes one during anal sex.

Respiratory Portal
The oral and nasal cavities are gateways to the respiratory tract. (portal of entry for the greatest number of pathogens)
Pathogens that are inhaled into the lower regions of the respiratory tract can cause pneumonia. The size of the microorganism affects the extent to which an organism is carried into the bronchial tree following inhalation.

Urogenital Portal
Portal of entry for sexually transmitted pathogens also known as Venereal diseases or STD. These diseases account for 4% of infections worldwide.
The microbes of STD's enter the skin or mucosa of the penis, external genitilia, vagina, cervix, and urethra.
Not all urogenital infections are STD's. Some of these infetions are cause by displaced organisms or buy opportunistic overgrowth of normal flora (yeast infections).
*The flow of urine helps to keep the kidney, ureter, bladder and upper urethra sterile.

Pregnancy that infect during pregnancy or Birth:
The placenta is usually an effective barrier against microorganisms in the maternal circulation but a few microbes such as the syphilis spiochete can cross the placenta and spread into fetal tissues.
Other infections such as genital herpes occur perinatally when the child is contaminated by the birth canal.
STORCH infections can cause spontaneous abortions, congenital abnormalities, brain damage, prematurity, and still birth.

Step 2---Attaching to the host: Adhesion Properties of Microbes

Microbe	Disease	Adhesion Mechanism
Neisseria gonorrhoeae	Gonorrhea	Fimbriae attach to genital epithelium
Escherichia coli	Diarrhea	Well-developed fimbrial adhesion
Shigella	Dysentery	Fimbriae can attach to intestinal epithelium
Vibrio	Cholera	Glycocalyx anchors microbe to intestinal epithelium
Treponema	Syphillis	Tapered hook embeds in host cell
Mycoplasma	Pneumonia	Specialized tip at ends of bacteria fuse tightly to lung epithelium
Pseudomonas aeruginosa	Burn, lung infections	Fimbriae and slime layer
Streptococcus pyogenes	Pharyngitis, impetigo	Lipotechoic acid and capsule anchor cocci to epithelium
Streptococcus mutans, S. sobrinus	Dental caries	Dextran slime layer glues cocci to tooth surface
Influenza virus	Influenza	Viral spikes react with receptor on cell surface
Poliovirus	Polio	Capsid proteins attach to receptors on susceptible cells
HIV	AIDS	Viral spikes adhere to white blood cell receptors
Giardia lamblia (protozoan)	Giardiasis	Small suction disc on underside attaches to intestinal surface

Step 3----Surviving Host Defenses:
Microbes are likely to encounter resistance from host defences when first entering the portal of entry. Phagocytes can engulf pathogens and destroy them.
Some microbes have antiphagocytic factors which make them resitant to phagocytes.

CAUSING DISEASE:
Virulence factors:
• exoenzymes – digest epithelial tissues & permit invasion of pathogens
• Toxigenicity – capacity to produce toxins at the site of multiplication – endotoxins – lipid A of LPS of gram-negative bacteria – exotoxins – proteins secreted by a living gram-positive and gram-negative bacteria • antiphagocytic factors – help them to kill or avoid phagocytes, include leukocidins and capsules
** A very virulent microorganism has an ID of one.

Differential Characteristics of Bacterial Exotoxins and Endotoxins

Characteristic	Exotoxins	Endotoxins
Toxicity	Toxic in tiny amounts	Toxic in higher doses
Effects on the body	Specific to a cell type	Systemic: fever, inflammation
Chemical Composition	small proteins	lipopolysaccharide of cell wall
Heat Denaturation @ 60 Deg. C	unstable	stable
Toxoid Formation	Can be converted to toxoid	cannot be converted to toxoid
Immune response	stimulate antitoxins	does not stimulate antitoxins
Fever stimulation	usually not	yes
manner of release	secreted from live cell	released from cell wall during lysis
Typical sources	A few gram positive and gram negative	All gram-negative bacteria

Stages of Infection-

Incubation period: Time between contact and first appearance of the signs or symptoms of infection. (2-30 days)
Prodromal period: A short period (1-2 days) of discomfort, when vague, notable symptoms of infection appear.
Invasion period: (Period of illness) When disease is most acute. Worst period.
Covalescence period: Signs and symptoms subside, one regains strength.

***Can be contagious in all stages.***

Sign- objective evidence (Fever, chest sounds, leukopenia, or tachycardia)

Symptom- subjective evidence (chills, nausea, itching, or headache) These are not measurable except by the patient.

Common signs and symptoms of infectious diseases

Signs	Symptoms
Fever	Chills
Septicemia	Pain, ache, soreness, irritation
Microbes in tissue fluids	Nausea
Chest sounds	Malaise, fatigue
Skin eruptions	Chest tightness
Leukocytosis	Itching
Leukopenia	Headache
Swollen lymph nodes	Nausea
Abscesses	Abdominal cramps
Tachycardia	Anorexia
Antibodies in serum	Sore throat

Sequelae- long-term permanent damage to tissue or organs

Acute Infection- sudden onset; generally short-lived (flu)

Chronic Infection- persistent, continuous infection.

PATTERNS OF INFECTION
A localized infection enters the body and stays in a specific tissue. A systemic infection is when the infection spreads to different sites and in the fluids (usually the blood). A focal infection is when the infection breaks free from the local infection and is then carried into other tissues. A mixed infection is when two or more infectious agents infect the same site.

Endemic- Disease that exhibits a relatively steady frequency over a long period of time in a particular geographic locale.
Sporadic- When occasional cases are reported at irregular intervals.
Epidemic- When prevalence of a disease is increasing beyond what is expected.
Pandemic- Epidemic across continents.
Prevalance- The total number of existing cases with respect to the entire population.
Incidence- The number of new cases over a certain time period.

TOXEMIA
A pattern of infection where the infection itself remains localized at the portal of entry, but the toxins produced by the pathogen are carried by the blood to the actual target tissue.

SEPTICEMIA
Clinical term for bacteria multiplying in the blood.

Factors that weaken host defenses and increase susceptibility to infection:

Old age and extreme youth (infancy, prematurity)

Genetic defects in immunity and acquired defects in immunity (AIDS)

Surgery and organ transplants

Organic disease: cancer, liver malfunction, diabetes

Chemotherapy/immunosuppressive drugs

Physical and mental stress

Other infections

Portal of Exit :Vacating the Host

Respiratory and Salivary Portals of Exit:
Mucus, Sputum, nasal drainage, and other moist secretions are the media of escape for the pathogens of the respiratory tract. Coughing and sneezing is very effective to release pathogens.
Droplets of saliva are the exit route for several viruses.

Epithelial Cells:

Fecal Exit:

Urogenital tract:

Removal of Blood or Bleeding:

Persistance of Microbes
In chronic infections the infectious agent retreats into a state call persistence or latency. Can periodically become active and produce a recurrent disease
Some diseases leave sequela in the form of long term or permanant damage to tissues or organs.

Sources and Spread of Microbes
Living Reservoirs
A carrier by definition is an individual who inconspicuously shelters a pathogen and spreads it to others without any notice.

Asymptomatic Carriers- are infected carriers but they show no symptoms.

incubation carrier-spread infection during incubation period

convalescent carrier-spread infection during the time they are recuperating and have no symptoms

chronic carrier-carries a latent form of the infection ("Typhoid Mary")

Passive Carrier- Process in which pathogens are picked up mechanically and transferred to other people. Most common in medical and dental personnel.

Nosocomial Infections - occur in the presence of compromised patients and pathogen in hospitals. These infections occur when indwelling medical devices are used or when treatments utilizing reusable instruments are implemented. The use of effective infection control measures helps to contribute to the management of nosocomial infections.

VECTOR is a live animal that transmits an infectious from one host to another (such as a mosquito)

Koch's Postulates- the principal criteria for determining the etiologic or causitive agents of an infection.
STEPS...
1- Find evidence of a specific type of microbe in every case of disease.
2- Isolate the microbe from an infected subject and cultivate it artificially in the lab.
3- Inoculate a healthy subject and observe results.
4- Reisolate the agent from this subject.

Controlling Microbes with Drugs

flattail — Tue, 23 Jun 2009 16:16:02 CDT

Drugs, Microbes, Host--The Elements of Chemotherapy
Antibacterial antibiotics

Penicillin- Derived from the mold Penicillium. Called a "semi-synthetic" when produced through microbial fermentation, and then chemically altered. Penicillin is still the drug of choice for gram-positive bacteria.

Semisytnhetic penicillins (ampicillin, carbenicillin, and amoxicillin) have a broader spectrum.

Alexander Fleming:

In 1928 he was studying staphylococci. He was already known as a great researcher, but also as a careless lab technician. After being away he noticed that many of his lab cultures had grown fungus around them. He threw them into disinfectant, but when someone asked what he had been working on he retrieved them. It was then that he saw a zone around the invading puss where bacteria could not seem to grow. He continued to isolate and extract from moldy bread and was able to identify it as being Penicillin. He began to investigate its antibacterial affect especially on gram-positive bacteria. Fleming published his findings, but not much attention was given to it. He found that is was too hard to isolate the antibiotic agent. Soon after Fleming had given up his research with Penicillin, Ernst Chain and Howard Florey began researching and mass producing it. When D-Day arrived they had enough to treat all the wounded soldiers.

Cephalosporins- Relatively new, but are the most commonly administered group of antibiotics. Produced from the mold Cephalosporium. Similar in structure and function of penicillins, but have a few advantages like: relatively large spectrum, resistant to penicillinases, fewer allergic reactions. There are 3 generations with each more effective than the last. These drugs will have "cef, ceph, or kef" in thier names. Most are given parentally, but some are given orally.

Aminoglycosides- Is made from Streptomyces (filamentous fungi-like soil bacteria.) Relatively broad spectrum because they inhibit protein synthesis.

Streptomycin & gentamicin are newer and less toxic. They are good to treat gram-negative rods like Escherichia, Psuedomonas, Salmonella, Shigella.

Tetracycline antibiotics- Semisynthetics derived from a species of Streptomyces. Blocks protein synthesis, effective against a wide variety of bacteria. Used to treat several types of STD's as well as Rocky Mt Spotted Fever, Lyme Disease, typhus, cholera, acne.

Side Effects: Toxic to growing teeth and bones, causes birth defects, can cause GI upset, sensitivity to sunlight, and can discolor tooth enamel. Can cause a superinfection, and should never be given to pregnant women, or children. Any woman taking a Tetracycline antibiotic would also be on some sort of birth control. Tetracycline can cause severe birth defects.

Chloramphenicol- Is a Streptomyces antibiotic, is a broad-spectrum, also blocks protein synthesis. Very toxic and only used when other options are not available.
New classes- Always looking for new antibiotics.

Competitive inhibition- drug competes with normal substrate for enzyme's active site.

Synergistic effect- an additive effect, achieved by multiple drugs working together, requiring a lower dose of each

Interferon- Anti viral therapy. It is a natural compound produced by many types of cells. It's activity is species specific. It appears to act by interfering with translation functions once the virus has entered the cell. It is produced by infecting human lymphocytes, lymphoblasts, or fibroblasts with a virus or exposing them to a chemical inducer. The cells respond by releasing interferon into the medium, and the material is then purified by a number of complex chemical steps. Alternatively, the gene for interferon production can be inserted in bacteria, allowing large-scale and efficient production of this complex protein (Cecil Textbook of Medicine,1988).

CHARACTERISTICS OF THE IDEAL ANTIMICROBIAL DRUG

Selectively toxic to the microbe but non toxic to host cells
Microbicidal rather than microbiostatic
Relatively soluble and functions even when highly diluted in body fluids
Remains potent long enough to act and is not broken down or excreted prematurely
Not subject to the development of antimicrobial resistance
Complements of assists the activities of the host's defenses
Remains active in tissues and body fluids
Readily delivered to the site of infection
Not excessive in cost
Does not disrupt the host's health by causing allergies or predisposing the host to other infections
Quinine
Inhibition of cell wall synthesis
Inhibition of nucleic acid synthesis, structure or function
Inhibition of protein synthesis
Disruption of cell membrane structure or function

Pathogen Targets of Antimicrobial Drugs
cell wall	cell membrane	ribosomes	DNA/RNA	Metabolic Pathway
penicillins	macrolides	erythromycin	fluoroquinolones	sulfa
cephalosporins	azoles	chloramphenicol	cyclovirs	trimethoprim
bacitracin	amantidine	aminoglycosides	flucytosine
vancomycin		tetracycline	rifampin

Here is another table organizing the information of pathogen targets of antimicrobial drugs in a different way

	Drugs Organized by Origin and Structure
	Beta-lactams		Aminoglycosides	Tetracyclines	Chloram phenicols	Sulfonamides
Names	Penicillins	Cephalosporins	Streptomyces derivatives	aureomycin terramycin		sulfa drugs
Brand/Generic names	Amoxicillin, Trimox, Penicillin VK	Keflex, Cephalexin				septra, bactrim sulfisoxazole, silver sulfadiazine, trimethoprim
Cell Target	cell wall	cell wall	protein synthesis	protein synthesis	protein synthesis	metabolic pathway
Side-effects	renal failure, neutropenia thrombocyto-penia,rash, seizures	renal failure seizures,	renal failure,vertigo, neuropathy,deafness, respiratory arrest,	photo-sensitivity, rash,	irreversible damage to bone marrow, anemia	allergic rash, renal failure, goiter,anemia,

Drugs that affect the bacterial cell wall
• Most bacterial cell walls contain a rigid girdle of peptidoglycan (protects cell from rupture in hypotonic environments).
• Penicillin and cephalosporin block synthesis of peptidoglycan by reacting with the enzymes required to complete this process, causing the cell wall to lyse.
Most of these drugs are active only in young, growing cells - old, inactive, or dormant cells don't synethize peptidoglycan.
• Penicillins do not penetrate the outer membrane and are less effective against gram-negative bacteria.
• Broad-spectrum penicillins and cephalosporins can cross the cell walls of gram-negative bacteria.

Test yourself:
- What drugs affect the bacterial cell wall? How do they do this?
- Why aren't penicillin and cephalosporins effective against old or dormant cells?
- Are penicllins and cephalosporins considered bactericidal or bacteristatic? Why?
- Are penicillins effective against gram-negative bacteria?

Drugs that inhibit nucleic acid synthesis
• May block synthesis of nucleotides, inhibit replication, or stop transcription
• Sulfonamides and trimethoprim block enzymes required for tetrahydrofolate synthesis needed for DNA & RNA synthesis.
• These types of drugs work by: competitive inhibition – drug competes with normal substrate for enzyme’s active site, or synergistic effect – an additive effect, achieved by multiple drugs working together, requiring a lower dose of each

Test yourself:
- How do drugs inhibit nucleic acid synthesis? (Three ways)
- What drugs inhibit nucleic acid synthesis?
- Two drugs blcok enzymes needed for DNA and RNA synthesis. What are they, and how do they work?
- What two methods do DNA-RNA-inhibiting drugs work by?

Drugs that block protein synthesis
• Ribosomes of eucaryotes differ in size and structure from procaryotes, so antimicrobics usually have a selective action against
procaryotes. But they can also damage the eucaryotic mitochondria.
• Aminoglycosides (streptomycin, gentamicin) insert on sites on the 30S subunit and cause misreading of mRNA.
• Tetracyclines block attachment of tRNA on the A acceptor site and stop further synthesis.

Test yourself:
- How do these drugs block protein synthesis?
- What eukaryotic structure can these drugs harm?

Drugs that disrupt cell membrane function
• A cell with a damaged membrane dies from disruption in metabolism or lysis.
• These drugs have specificity for a particular microbial group, based on differences in types of lipids in their cell membranes.
• Polymyxins interact with phospholipids and cause leakage, particularly in gram-negative bacteria
• Amphotericin B and nystatin form complexes with sterols on fungal membranes which causes leakage.

Test yourself:
- Why does a cell with a damaged membrane die?
- Drugs that damage bacterial cell membranes have specificity based on what?
- What drugs disrupt cell membrane function?
- Which drug works well against gram-negative bacteria?
- Which drugs work well against fungi?

Antimicrobial Drugs that effect metabolic pathways
Sulfonnamides and trimethopim are drugs that act by mimicking the normal substrate of an enzyme in a process called Competitive inhabition. They are supplied to the cell in high concentrations to ensure that a needed enzyme is constantly occupied by the metabolic analog rather than the true substrate of the enzyme. As the enzymeis no longer able to produce a needed product, cellular metabolism slows or stops.Sulfonames and trimethoprim interfere with folate metabolim by blocking enzymes required for the synthesis of tetrahydrofolate, which is needed by bacterial cells for the synthesis of folic acid and eventual production of DNA and RNA and amino acids.

Q: The golden age of antibiotics began in 1928 with Sir Alexander Fleming's discovery of an antibacterial compound he called what?
a. Arsenic
b. Penicillin
c. Sulfonamide
A: Penicillin

Interactions Between Drugs and Microbes
Antimicrobial drugs are used in two different ways. To disrupt the cell processes of bacteria, fungus, or protozoa, or to inhibit virus replication. Drugs should be able to kill microbial cells with out doing any harm to their host cells. This is called selective toxicity. Penicillin is an example of a drug with selective toxicity. It blocks synthesis of the cell wall in bacteria and has low toxicity and little effect on the host cell wall.

Q: Which of the following is not a category of antimicrobial drugs?
a. Those that inhibit protein synthesis
b. Those that interfere with cell membrane structure and function
c. Those that inhibit mRNA processing in the nucleus
A: Those that inhibit mRNA processing in the nucleus

Q: Antimicrobials that block nucleic acid synthesis may act in all but which of the following manners?
a. They can block DNA transcription
b. They can block the synthesis of DNA and RNA nucleotides
c. They can inhibit the action of tRNA
A: They can inhibit the action of tRNA

Interactions Between Drugs and Host:
During an infection the microbe is living in or on a host; therefore the drug is administered to the host though its target is the microbe. So with that in mind the effect of the drug on the host must always be considered. There are three major side effects of antimicrobials are toxicity to organs, allergic reactions, and problems resulting from suppression or alteration of normal flora.

Toxicity to Organs:
Drugs can affect the following organs: the liver (hepatotoxic), kidneys (nephrotoxic), gastrointestinal tract, cardiovascular system and blood-forming tissue (hemotoxic), nervous system (neurotoxic), respiratory tract, skin, bones, and teeth.

Allergic Responses to Drugs:
One of the most frequent drug reactions is heightened sensitivity, or allergy. This reaction occurs because the drug acts as an antigen and stimulates an allergic response.

Suppressing and Alteration of the Microflora by Antimicrobials:
Most normal healthy body surfaces provide numerous habitats for virtual "garden" of microorganisms. These normal colonists are called flora or microflora and is mostly of harmless or beneficial bacteria, but a small number can potentially be pathogens. Antimicrobials that destroy most but not all normal flora allow the unaffected normal flora to overgrow, causing a superinfection.

Considerations in Selecting an Antimicrobial Drug
The three major considerations necessary to choose an effective antimicrobial are the nature of the infecting microbe, the microbe's sensitivity to available drugs, and the overall medical status of the infected host.
The effectiveness of antimicrobial drugs is being compromised by several alarming trends: inappropriate prescription use of broad-spectrum instead of narrow-spectrum drugs, use of higher-cost drugs, sale of over-the-counter antimicrobials in other countries, and lack of sufficient testing before prescription.

External links to drug companies describing various antibacterial drugs

Drug Resistance
You can listen to a podcast from the CDC discussing extensively drug resistant tuberculosis (XDR TB).

Antibacterial Antibiotics

Penicillins: large and diverse group. Can be made in a lab. Major source is Penicillium chrysogenum.

Cephalosporins: the majority of all antibiotics prescribed. Able to alter beta-lactam ring. Broad spectrum and resistant to most penicillin's. Cause fewer allergic reactions. Three generations.

Other Beta-lactam Antibiotics

Imipinem: broad spectrum drug used for infections with aerobic and anaerobic pathogens.

Aminoglycosides: made up of 2 or more sugars and an aminocyclitol ring. Broad spectrum, inhibits protein synthesis. Used on aerobic gram-negative rods and some gram-positive bacteria.

Tetracycline antibiotics: Broad spectrum. Block protein synthesis.

Chloramphenicol: Potent and very broad spectrum. Blocks formation of peptide bonds. Is not derived from a natural source. Very toxic. May cause irreversible damage to bone marrow.

Other Streptomyces antibiotics
Bacillus antibiotics
-new classes

Therapeutic Benefits of Food

Yogurt has been shown to control Staphylococcus infections

Garlic extract can inactivate viruses and destroy bacteria

Cranberry juice research indicates that it can keep E.coli from attaching to tissues

Zinc keeps the common cold virus from attaching

Apple juice, fruit juices and tea contain natural antiviral substances

Questions:	Q&A Page~~Home Page~~Top of Page

flashcards for this chapter are at www.flashcardexchange.com under kevin youngs micro chapter 12

Questions: Q&A Page~~Home Page~~Top of Page

1. When did Sulfa "hit" the market?
a. 1920's
b. 1940's
c. 1950's
d. 1930's

2. During WW II which country started "rediscovering" the effects of Penicillin?
a. England
b. Germany
c. United States
d. France
e. none of the above

3. Who actually discovered compound 606, also known as salvarsan?
a. Robert Koch
b. Louis Pasteur
c. Alexander Fleming
d. Paul Ehrlich

4. A compound synthesized by bacteria or fungi that destroys or inhibits the growth of other microbes is a/an
a. Synthetic drug
b. antibiotic
c. antimicrobial drug
d. competitive inhibitor

5. Which of these are involved in osmotic lysis of the cell well?
a) Penicillins
b) Cephalosporins
c) Cycloserine
d) Vancomycin
e) All of the above
f) None of the above

6. Which of these drugs do not affect the nucleic acid synthesis?
a) Sulfonamides
b) Trimetoprim
c) Polymyxins
c) Chloroquine
d) Quinolones
e) acyclovir

7. Which drugs are competitive inhibitors by occupying the binding site of the enzyme and blocking the substrate from the site?
a) Sulfonamides (sulfa drugs) and trimethoprim
b) Cycloserine and vancomycin
c) Amphotericin B and nystatin

8. Do beta-lactams drugs destroy all of the targeted bacteria cell wall? If not, then why? Why are human cells not effected?

9. What was the first known treatment for syphilis?
a) soybean curd applied topically
b) myrrh and frankincense
c) arsenic and mercury
d) penicillin

10. Which is not a characteristic of an ideal drug?
a) microbicidal and microbiostatic
b) remains potent long enough to act
c) readily delivered to the site of infection
d) doesn’t lead to microbial resistance

11. Chemotherapeutic agents are described with regard to:
a. origin
b. range of effectiveness
c. naturally produces
d. chemically synthesized
e. all of the above

12. Which bacteria would be the best the the drug spectrum for both gram + and gram -?
a. narrow spectrum
b. medium spectrum
c. broad spectrum

13. What inhibits DNA unwinding enzymes or helicases?
a. Penicillin
b. Chloroquine
c. Acyclovir
d. Azidothymidine

14. Tetracycline block the attachment of:
a. mRNA
b. inhibition of 30s subunit ribosome
c. tRNA
d. inhibition of 50s subunit ribosome

15. This was the first penicillin that became the patent for all other "cillins":
a. V
b. G
c. A
d. C

16. The adverse effect of tetracycline given to young children is...
a. allergies
b. joint damage
c. discoloration of teeth
d. dependency on drug

17. Which of these drugs com

18. Which drug is able to alter the beta-lactum ring?
a. penicillin
b. cephalosphorins
c.aminoglycosides
d.tetracycline

19. Yogurt has been shown to control_________.
a. alergies
b. fungus
c. E.coli
d. staphylococcus

20. Most antiheminthic drugs function by:
a. weakining the worms so they can be flushed out by the intestine
b. infibiting worm metabolism
c. blocking the absorption of nutrients
d. inhibiting egg production

21. A patient has a red circular rash on his arm and fever, malaise, and joint pain. The most appropriate treatment is:
a. penicillin.
b. chloroquine.
c. anti-inflammatory drugs.
d. rifampin.
e. no treatment.

22. Some of the benifits of interferon are:
a. reduce the time in healing
b. preventing some symptoms
c. slowing the progress.
d. all of the above.

The Squiggly Wiggly Bad Guys

flattail — Tue, 23 Jun 2009 16:14:42 CDT

Miscellaneous Bacterial Agents of Disease

SPIROCHETES

Spirochetes have a helical form. The majority of spirochetes are free-living saprobes or commensals of animals and are not primary pathogens. They are motile, gram-negative, and have enclosed flagella. They multiply quickly as you can see. Corkscrew-shaped bacteria. Bacteria are simple, unicellular organisms that are classified in the kingdom Monera (also called kingdom Prokaryotae). They have prokaryote cells, which means that they lack a nuclear membrane and other complex features. They move by means of two or more axial filaments, which are bundles of fibers that spiral around the cell body. Spirochetes show no evidence of any sexual life cycle and reproduce asexually by transverse fission, in which the organism divides in two across its width.

Three spirochetes - human pathogens

Treponema- thin, regular, coiled cells. They don't live freely in the environment; humans are the natural host. Extremely fastidious & sensitive. Treponema lives in the oral cavity, intestinal tract & perigenital region.Causes syphilis (both venereal and congenital). These are parasites and if you want to cultivate them in a lab you need to do it on live cells.They stain very poorly because their thickness approaches the resolution of the light microscope. They are delicate organisms requiring pH in the range 7.2 to 7.4, temperatures in the range 30°C to 37°C and a microaerophilic environment.

Leptospira- tight, regular individual coils with a hook at both ends. Bacteria found in urine of many different animals. Also found in skunks. Infection occurs from contact. Mainly tropical. It is caused by bacteria of the genus Leptospira. In humans it causes a wide range of symptoms, and some infected persons may have no symptoms at all. Symptoms of leptospirosis include high fever, severe headache, chills, muscle aches, and vomiting, and may include jaundice (yellow skin and eyes), red eyes, abdominal pain, diarrhea, or a rash. If the disease is not treated, the patient could develop kidney damage, meningitis (inflammation of the membrane around the brain and spinal cord), liver failure, and respiratory distress. In rare cases death occurs.

Borrelia- large, 3-10 coils. Infection transmitted by vectors such as ticks or lice. Causes lyme disease. Can progress to cardiac and neurological damage. Borrelia burgdorferi, also referred to as Lyme Disease is caused by a spirochete. Lyme disease is typically carried by the lxodes family of ticks. These include the deer tick. This gram-negative bacterium is stained by ordinary dyes such as crystal violet and carbofuchsin.

TREPONEMA PALLIDUM

-Humans are the only host and the bacteria cannot survive very long without humans. They are very sensitive, easily destroyed by heat, drying, disinfectants, soap, high oxygen, and pH changes.They can live in the oral cavity, intestinal tract, and perigenital regions of humans.
-Causes of syphilis are: mainly spread through sexual contact. Can be spreed to a fetus in utero. Medical personel can get from contact with body fluids.
-The pathogens are very strict parasites with complex growth requirements that necessitate cultivating them in live cells.
-Brought into direct contact with mucous membranes or abraded skin, binds avidly by its hooked tip to the epithelium
-At the binding site, the spirochete multiplies and penetrates the capillaries. Within a short time, it moves into the circulation, and the body is literally transformed into a large receptacle for incubating the pathogen--virtually any tissue is a potential target.
-Produces no toxins and does not kill cells directly. Despite action of phagocytes and antitreponemal antibodies, the body's cell mediated immune responses are unable to contain it.
-Infectious dose is 57 organisms (low dose compared to other bacteria)
-Very effective treatment is Penicillin G

SYPHILIS
History of Syphilis
Spirochette syphillis on the head of a sperm
Syphilis was first recognized at the close of the fifteenth century in Europe. Outbreaks followed Columbus' return from the New World (he did more than look for gold and spices on his trip...what happens in the New World stays in the New World).

-Syphilis is mainly spread through an infected sexual partner and the risk of transmitting it is 12% to 30%
-Reported cases have decreased in the last decade, but in some populations it is increasing largely among the gay and bisexual population or men in large urban areas. Also in larger metropolitan areas among prostitutes, their contacts, and intravenous drug users.
-Specific factors that account for the virulence of the syphilis spirochete appear to be the outer membrane proteins.
-At the initial point of contact the bacteria multiplies, penetrates the capillaries , and enters the circulation system. The body then becomes a large incubation chamber for this bacteria and virtually any tissue is a potential target. It produces no toxins and does not kill cells directly. Despite action of phagocytes and antirreponemal antibodies, the body's immune system is unable to contain it. During the incubation stage there are no symptoms (this lasts about three weeks), but in the next two stages it makes its self known.
-Untreated syphilis is marked by distinct clinical stages designated as primary, secondary, and tertiary syphilis. Also has latent periods of varying durations during which the disease is quiescent.

Q: Which of the following is not a factor that contributed to the worldwide transmission of syphilis that began in the latter 15th century?
a. The evolution of Treponema pallidum from a related subspecies.
b. Sailors returning with Christopher Columbus from the West Indies brought the disease with them.
c. The European population was sexually promiscuous during this period.
A: Sailors returning with Christopher Columbus from the West Indies brought the disease with them.

Stage	Average Duration	Clinical Setting
Incubation	3 weeks	No lesion; treponemes adhere and penetrate the epithelium; after multiplying, they disseminate
Primary	2-6 weeks	Initial appearance of chancre at inoculation site; intense treponemal activity in body; chancre later disappears(small red bumps). Breaks down and leaves a shallow crater with firm margins, usually on genitals but can also leave on: lips, oral cavity, nipples, fingers and rectum.
Primary latency	2-8 weeks	Healed chancre; little scarring; treponcemes in blood; few if any symptoms. Bacteria still remains busy.
Secondary	2-6 weeks after chancre leaves	Skin, mucous membrane lesions; hair loss; patient highly infectious, fever, headache, sore throat, lymphadenopathy; followed by a full body rash, this are spirochetes. This is the stage that patients are most infectious.symptoms can persist for months
Latency	6 months to 8 or more years	Treponemes quiescent unless relapse occurs; lesions can reappear
Tertiary	Variable, up to 20 years	Fatal to organs if it reaches this stage. aortic wall could rupture, tumors develop,Brain, cranial nerves, spinal cord, Neural, cardiovascular symptoms; gummas develop in organs; seropositivity

PRIMARY SYPHILIS [first stage]:

-3 weeks after initial contact
-Appearance of a hard chancre (the primary sore of syphilis that forms at the site of penetration by treponema pallidum. It begins as a hard, dull red, painless papule that erodes from the center). The chancre enlarges and breaks down, leaving a shallow crater with firm margins.
-Mostly chancres appear on the internal or external genitalia, but about 20% occur on lips, nipples, fingers, or around the anus.
-Tend to be painless so chancres can be unnoticed
-Lymph nodes draining the affected region become enlarged and firm, but systemic symptoms are usually absent.
-The chancre spontaneously heals without scarring in 3-6 weeks, but healing is deceptive, because the spirochete has escaped into the circulation and is entering a period of tremendous growth.
-You can diagnose the primary stage of syphilis through a dark-field microscope
-Treatment is Benzathine, Penicillin G, Aqueous Benzyl, or Procaine Penicillin.

SECONDARY SYPHILIS [second stage]:
-2 to 8 weeks after chancre leaves.
-By now many systems of the body have been invaded, and the signs and symptoms are more profuse and intense.
-Skin, mucous membrane lesions; hair loss; fever, headache, and sore throat, followed by lymphadenopathy and a peculiar red or brown rash that breaks out on all skin surfaces, including palms and soles.
-Like the chancre. the lesions contain viable spirochetes and disappear spontaneously in a few weeks.
-Major complications, occur in the bones, hair follicles, joints, liver, eyes, and brain, can linger for months and years.
- Patient most infectious at this stage.
-Diagnose with dark-field testing; serological tests (+)
-Treatment is just double doses of penicillins listed above.

TERTIARY SYPHILIS [third stage]:
-After resolutions of secondary syphilis, about 30% of infections enter a highly varied latent period that can last 6 months up to 20 years or even more.
-Antitreponeme antibodies are detected but not the parasite itself.
-The final stage of disease is quite rare today because of widespread antibodies to treat other infections.
-When patient reaches this phase, numerous pathological complications occur in susceptible tissues and organs.
-Cardiovascular syphilis results from damage to the small arteries in the aortic walls. (the walls weaken
and the aorta is subject to distension and fatal rupture, and may damage the aortic valves causing heart
failure)
-Painful swollen syphilitic tumors called gummas (a nodular, infectious granuloma characteristic of tertiary syphilis) develop in tissues such as liver, skin, bone, and cartilage.
-Gummas are usually benign and only occasionally lead to death, but can impair function.
-Neurosyphilis can involve any part of the nervous system, but shows particular affinity for the blood vessels in the brain, cranial nerves, and dorsal root of the spinal cord.
-Reactions include severe headaches, convulsions, mental derangement, atrophy of optic nerve, blindness, and the Argyll-Robertson pupil (small pupils that do not react to the light, and is perhaps the most common sign)
-Destruction of part of the spinal cord leads to muscle wasting and loss of activity and coordination.
-Diagnosis: Treponeme may be demonstrated by DNA analysis of tissue
-Treatment is the same as secondary syphilis.

CONGENITAL SYPHILIS: (passage through placenta)
-Treponema pallidum can pass from a pregnant women's circulation into the placenta and be carried throughout the fetal tissues.
-Can occur in any of the three trimesters, though most common in the second or third.
-The pathogen inhibits fetal growth and disrupts critical periods of development with varied consequences, ranging from mild to the extremes of spontaneous miscarriage or stillbirth.
-Usually first detected 3 to 8 weeks after birth.
-Infants show signs of profuse nasal discharge, skin eruptions, bone deformation, and nervous system abnormalities
-The late form gives rise to an unusual assortment of stigmata in the bones, eyes, inner ear, and joints and causes the formation of Hutchinson's teeth (notched, barrel-shaped incisors)

Diagnosing: One rapid, direct method to detect primary, early congenital, and, to a lesser extent, secondary syphilis, is dark-field microscopy of a suspected lesion. Lesions are gently squeezed or scraped to extract clear serous fluid. A wet mount prepared from the exudate is then observed for the characteristic size, shape, and motility of T. pallidum. A single test is not 100% because the patient may have removed the organism by washing, so follow up tests recommended.
-Also a immunofluorescence staining with monoclonal antibodies give a direct test.
-Patient samples can also be tested with a DNA probe specific to various gene sequences.
-If microscopy tests are negative, serological tests looking for presence of antibodies can be diagnostic (but false positive results are possible)
(A) This is tested in premartial blood tests
(B) This is suggested for people in high risk groups
(C) If a patient tests positive, there are more specific tests that can verify an active infection.

Treatment:
-Originally no good treatment, Mercury was used (unfortunately the treatment was worse than the disease)
-Paul Ehrlich developed Salvarsan in 1910
-Penicillin in the 1940's
-Penicillin G is the wonder drug and treatment in all three stages. If allergic to penicillin they will administer tetracycline and erythromycin. Public health departments and physicians are charged with the task of questioning the patients and tracing their contacts. Those people, even if they don't show any signs of syphilis will immediately be given penicillin
-Important to complete the course of antibiotics (at least 7 days)
-Condoms provide good protection
-Vaccine may be available in the future

A NOTE ABOUT A DARK EVENT IN HUMAN EXPERIMENTATION (Kevin did mention this in class)
-One of the most disturbing events in the study of syphilis in the US. In 1932, the US government conducted a study called the Tuskegee Study of Untreated Syphilis in the Negro Male, which eventually involved 399 indigent African-American men living in the South. Infected men were recruited into the study, which sought to document the natural progression of the disease. These men were never told they had syphilis, and were never treated, even after penicillin proved to be an effective cure. The study ended in 1972, after it became public. In 1997, the government issued a public apology for permitting the study to proceed for so long, and began paying millions in compensation to the victims and their heirs.
*2006 cdc statistics
LEPTOSPIRA:

-Marked by tight, regular, individual coils with a bend or hook at one or both ends.
-Only two species in the genus:
-Leptospira interrogans (which causes leptospirosis in humans and animals a zoonosis, such as rodents), and
-Leptospira biflexa (a harmless, free-living saprobe).

These two species are serologically, genetically, and physiologically distinct
-Leptospirosis is a zoonosis (an infectious disease indigenous to animals that humans can acquire through direct or indirect contact with infected animals)
-Skunks, rodents, raccoons, foxes and some domesticated animals; horses, dogs, cattle, and pigs.
-All over the world but mostly in the tropics
-Leptospira interrogans is the one that shed in the urine of an infected animal and can survive in the soil or water for several months (*remember the picture with the cow peeing and the guy laying in the grass behind it.)
-Infections occur almost entirely through contact of skin abrasions or mucous membranes with animal urine
-Not associated with bites, inhalation, or human contact
-In US 50-60 cases per year reported among older kids, and young adults expose to polluted water, and soldiers involved in jungle training.
-Sudden high fever, chills, headache, vomiting are early symptoms
-Damage to kidneys, liver, brain, and eyes if left untreated

Q: How are Leptospira species transmitted from their animal reservoirs to humans?
a. Animal bites
b. Contact with urine from an infected animal
c. Human contact with infected animals
A: Contact with urine from an infected animal

Diagnosis: A fast, specific, effective test call the macroscopic slide agglutination test is most often employees for routine screening. Then live or formalized L. interrogans is mixed with the patient's serum and observed for agglutination or lysis with a dark-field microscope.

Treatment: Early treatment with penicillin or tetracycline reduces symptoms and shortens the course of disease. But delayed therapy is less effective. Strain-specific vaccines made from killed cells are available but these can confer protection only to a specific endemic strain. Vaccination aimed toward combat troops training in the jungle and animal care and livestock workers. The best controls are to wear protective footwear and clothing and to avoid swimming or wading in livestock watering pools.

BORRELIA:

-Distinct from other pathogenic spirochetes. They are lager, and contain 3-10 irregularly spaced, loose coils with many periplasmic flagella
-Human infection is transmitted by some type of arthropod vector, usually ticks or lice
-The two most important diseases caused by borrelia are relapsing fever and Lyme Disease

Relapsing fever
-Usually caused by ticks, but can be spread by squirrels, chipmunks or other wild rodents. [The human is usually an accidental host]
-Tick-borne relapsing fever occurs sporadically in the US but the incidence of infection is higher in tropical areas. Whenever famine, war or natural disasters are coupled with poor hygiene, crowding and inadequate medical attention, the incidence rises.
-The disease begins with a 2-15 day incubation period, causing the host to experience high fever, shaking, chills, headache and fatigue. It progresses to include nausea, vomiting, muscle aches and abdominal pain. Extensive damage to the liver, kidneys and cranial nerves occur in many cases. 50% of patients hemorrhage into organs, and some develop rash. Untreated cases may have a 40% mortality rate.
-The immune system has a difficult time trying to control relapsing fever, since the surface antigens change during growth. This means the initial antibodies produced by the body become useless.
-Blood smears are used to diagnose
-Chloramphenicol, erythromycin and doxycycline are used as treatment

Lyme Disease
-Is caused by Borrelia burgdorferi
-Transmitted mainly by hard ticks
-The cycle of Lyme disease: (complex 2-year cycle involving mice and deer)
1-Newly hatched larvae become infected when they feed on small animals such as mice, which harbor the spirochete. The larvae continue development through this year.
2- In the second year the larvae molt into the nymph, an aggressive feeding stage.
3- The nymph takes blood from a number of hosts, including deer and humans.
4- On deer, the nymph matures into adult male and female ticks, which mate. The female lays eggs in plant litter, where they hatch and once again begin the cycle
-Incidence showing upward trend with greatest concentrations in areas having high number of mice and deer.
-Lyme disease is non-fatal but often evolves into slowly progressive syndrome that mimics neuromuscular and rheumatoid conditions
-An early symptom in 50% to 70% of cases is a rash at the site of a larval tick bite. The lesion, called erythema migrans, can appear something like a bull's eye
-Begins as tick bite and rash, progresses to fever, headache, stiff neck, and dizziness.
-After weeks or months, it can attack joints, cardiac and neurological symptoms (facial palsy) develop and some people acquire chronic neurological complications that are severely disabling
-Diagnosis can be difficult. Blood tests and serum tests are used for earlier stages, and spirochetal DNA tests are used for late-stage diagnosis
-Dogs can also acquire Lyme disease. There is a vaccine for dogs, but the vaccine for humans has been discontinued. Use DEET spray when going into areas where ticks may be!
-Early treatment with tetracycline and amoxicillin is effective
-Later treatment other antibiotics such as ceftriaxone and azithromycin are used.
Precaution measures to avoid Lyme disease
- it is suggested to use deet however this is not as helpful as many would think, from personal experience it seems to have little or no effect on ticks.
- The best preventive measure is to do regular tick checks. while in the field ocasoinally check your clothes to find the tick before they make contact with your skin. Also do a good check all over your body when you are at home when you can remove your clothes.
- Another thing that helps is wearing pants, boots, and long sleeve shirts so you have a better chance finding the ticks before they make contact with your skin.
http://www.cdc.gov/Features/LymeDisease/
ticks
Q: How are Borrelia species able to evade the immune system and avoid destruction in infected humans?
a. They have a capsule that makes phagocytosis difficult.
b. They remain inside the arthropod vector and are never exposed to the immune system.
c. They alter their surface antigens during growth.
A: They alter their surface antigens during growth.

CURVIFORM GRAM-NEGATIVE BACTERIA AND ENTERIC DISEASES

VIBRIO CHOLERAE

-Characteristics: Comma-shaped rods, with a single polar flagella

-The cause of Cholera
-Shares many characteristics with Enterobacteriaceae
-Can be free-living in certain endemic regions
-It ranks among the top seven causes of morbidity and mortality, affecting millions of people in endemic regions of Africa and Asia.
-Spread in the US mainly by contaminated food and water
- After being ingested with food or water. V. cholerae uses several virulence factors to help it survive the acidity of the stomach:

-The size of infection dose is 10^8 cells, due to the hostile environment
-Certain types of food might shelter the pathogen through the stomach environment
-An enterotoxin called cholera toxin (CT) disrupts the physiology of intestinal cells. When the toxin binds to certain intestinal receptors, a second system is activated and the intestinal cells shed large amounts of electrolytes. This causes profuse water loss.

Questions:	Q&A~~Home Page~~Top of Page

-The vibrios penetrate the mucous barrier at the duodenum and jejunum, and rest near the surface of the epithelial cells. They are strictly epipathogens and do not invade the mucosa or enter the cells
-Most dangerous in elderly or very young
-After and incubation period of a few hours to a few days, symptoms begin abruptly with vomiting, followed by copious watery feces called secretory diarrhea (contains flecks of mucous, hence "rice-water stool")
-Fluid losses are nearly one liter per hour in severe cases and an untreated patient may lose up to 50% of body weight during the course of this disease.
-Cases "rice-water" stools, acidosis, potassium depletion, and blood loss in addition to dehydration that causes the patient to have muscle cramps, severe thirst, flaccid skin, sunken eyes, and in some children, coma and convulsions
-Secondary circulatory problems include hypotension, tachycardia, cyanosis, and collapse from shock within 18 to 24 hours
-If left untreated death can occur in less than 48 hours, and mortality rate approaches 55%.
-V. Cholerae can be clinically diagnosed in epidemics, but can also be identified in the lab from stool samples or direct dark-field microscopic observation. V. Cholerae have curved cells with brisk, darting movements
-Treatment is prompt replacement of h2o and electrolytes, tetracycline and some sulfa can stop diarrhea
ORAL REHYDRATION THERAPY: consists of a mixture of electrolytes sodium chloride, sodium bicarbonate, potassium chloride, and glucose or sucrose dissolved in water. When administered early in amounts ranging from 100 to 400 ml/hour, the solution will restore patients within 4 hours. Patients who are unconscious or with severe dehydration will need IV therapy.

Other Vibrio:
-salt-tolerant inhabitants of coastal waters, associate with marine vertebrates.
-Vibrio - gastroenteritis from raw seafood
-Vibrio vulnificus- gastroenteritis from raw oysters.

Helicobacter pylori

-H. pylori thrives in the acidic stomach environment
-peptic ulcers
-Causes inflammatory condition called gastritis as well as 90% of stomach and duodenal ulcers, an apparent co-factor in the development of adenocarcinoma of the stomach
-First detected in 1979 in patients with stomach ulcers by J. Robin Warren. They actually swallowed a good-sized inoculum and both developed a short-term of gastritis. He and his assistant, Barry J. Marshall, were awarded the Nobel Prize in 2005 for their discovery
-Occurs in stomachs of 25% of healthy middle-aged adults and more than 60% of healthy adults over 60
-Probably transmitted person to person by the oral-oral or oral-fecal route. May be spread by houseflies acting as mechanical vectors
-Seems to be acquired early in life and carried asymptomatically until its activities begin to damage the digestive mucosa.
-First it bores through outermost mucus that lines the epithelial tissue, then it attaches to specific binding sites on the cells and then entrenches itself.
-H. pylori shares the same receptor as the O blood type, which means that type O blood have a higher rate of ulcers
-Another protective adaptations the formation of urease, an enzyme that converts urea into ammonium and bicarbonate, both alkaline compounds that can neutralize stomach acid.
-appears to be a cofactor in a stomach cancer
-Diagnosis: H. pylori is isolated from biopsy specimens. Because it gives off large amounts of urease, it can be initially identified by inoculating a test that detects pH changes.
-A less invasive technique is the urea breath test. This test involved swallowing labeled urea that gives off radioactive CO2 in exhaled air if H. pylori is present. Hence, diagnosis can be made with a breath test.
-Treatment: Gastritis and ulcers have traditionally been treated with drugs (tagamet, zantac). They must be taken continuously for indefinite periods and relapses are common. The newest recommended therapy is 2 to 4 weeks of clarithromycin to eliminate the bacterial infection, and drugs that inhibit the formation of stomach acid. this regimen can actually cure the infection and eliminate symptoms.

Campylobacter jejuni
-Slender, short spirals or vibrios with one or more flagella. Often appear S-shaped
-Considered one of the most important causes of bacterial gastroenteritis worldwide.
-In US 2.5 million cases occur every year.
-Common in poultry flocks, this bacterium has become the leading cause of bacterial food-borne diseases in the US. Exposure to a small number of microbes can cause illness. Most infected persons recover within a week.
-Transmitted through contaminated beverages and food, especially water, milk, meat, and chicken.
-When ingested, they reach the mucosa at the last segment of the small intestine (ileum) near its junction with the colon. They adhere, burrow through the mucus, and are taken into intestinal cells and multiply.
Symptoms include: headache, fever, abdominal pain, and bloody or watery diarrhea.
-The mechanisms of pathology involve a heat-labile enterotoxin called CJT that stimulates secretory diarrhea like cholera.
Diagnosis: Made with fecal samples and occasionally blood samples. Examine the feces with a dark-field microscope, which accentuates the characteristic curved rods and darting mobility.
Treatment: In most instances, rehydration and electrolyte balance therapy. In more serious cases, erythromycin, tetracycline, aminoglycosides, or quinolones.

Ricketsia
-Obligate intracellular parasites
-Gram-negative cell wall
-Among the smallest bacteria
-Nonmotile plemorphic rods or coccobacilli
-Ticks, fleas & louse are involved in their life-cycle
-Bacteria enter endothelial cells & cause necrosis of the vascular lining- vasculitis, vascular leakage & thrombosis
-Treat with tetracycline & chloramphenicol

Four Types of Rickettsiosies
1-Epidemic typhus- carried by lice, starts with a high fever, chills, headache, rash.
2-Endemic typhus- harbored by mice and rats, occurs sporadically in areas with high flea infestation, mild symptoms
3-Rocky mountain spotted fever- carried by dogs and wood ticks, most cases are from the east, spotted rash, can damage heart and CNS
4-Ehrlicha genus contains 2 species of rickettsias; tickborn bacteria cause human monocytic & granulocytic ehrlichiosis

Chlamydia
-Obligate intracellular parasites
-small gram-negative cell wall
-alternate between 2 stages; elementary body- small metabolically inactive, extracellular, infectious form. Reticulate body- grows within host cell vacuoles

Chlamydia trachomatis
-Human reservoir, Two Strains
-Trachoma- attacks the mucous membranes of the eyes, genitourinary tract, and lungs
-Ocular trachoma- severe infection, deforms eyelid and cornea, can cause blindness
-Inclusion conjunctivitis- occurs as babies pass through the birth canal, is prevented by prophylaxis
-STD- urethritis, cervicitis, salpingitis (PID), infertility, scaring
-Lymphogranuloma venereum- disfiguring disease of the external genitalia and pelvic lymphatics

Mycoplasma
Naturally lack cell walls, and are highly plemorphic. They require special lipids from host cell membranes. They are treated with tetracycline and erthyromycin. M. pneumonia- primary atypical pneumonia; pathogen slowly spreads over interior respiratory surfaces causing fever, chest pain, and sore throat. M. hominis and Ureplasma erealyticum- weak sexually transmitted pathogens.

Questions: Q&A~~Home Page~~Top of Page

1. Why are certain microscopes used instead of staining to see treponema, leptospira and borrelia spirochetes?

2. What is the major side effect of cholera that can lead to death?
a. fever
b. dehydration
c. heart arrhythmia
d. stroke

3. What was the cause of the London cholera outbreak?
a. unsanitary bathing conditions
b. improper disposal of the dead
c. intake of contaminated water from a street pump
d. eating undercooked meat

4. Which blood type is at higher risk for ulcers?
a. A+
b. B-
c. O
d. B+

5. Which of the following is the common cause of food poisoning?
a. Campylobacter jejuni
b. Vibrio cholera
c. Borrelia burgdorferi
d. Leptospira biflexa

6. Humans are the only natural host for this bacteria and is mainly spread through sexual contact.
a. Rickettsia prowazekii
b. Chlamydia trachomatis
c. Leptospira
d. Treponema pallidum

7. A man was admitted into a hospital while vacationing in Brazil. He had a temperature of 103 C, chills, headache, muscle aches, and conjunctivitis. On testing, they found this pathogen in his blood and cerebrospinal fluid.
a. Treptonema pallidum
b. Leptospira
c. Rickettsia prowazekii
d. Chlamydia trachomatis

8. A gumma is:
a. the primary lesion of syphilis
b. a syphilitic tumor
c. the result of congenital syphilis
d. a damaged aorta

9. The treatment choice for syphilis is:
a. tetracycline
b. antiserum
c. penicillin
d. sulfa drugs

10. Lyme disease is caused by _______ and spread by ______.
a. Borrelia recurrentis, lice
b. Borrelia burgdorferi, fleas
c. Borrelia hermsii, ticks
d. Borrelia burgdorferi, ticks

11. Relapsing fever is spread by:
a. lice
b. ticks
c. animal urine
d. a and b

12. The best therapy for cholera is:
a. oral tetracycline
b. oral rehydration therapy
c. antiserum injection
d. oral vaccine

13. Rickettsias and chlamydias are similar in being
a. free of a cell wall
b. the cause of eye infections
c. carried by arthropod vectors
d. obligate intracellular bacteria

14. Which of the following is not an arthropod vector of rickettsioses?
a. mosquito
b. louse
c. tick
d. flea

15. Chlamydiosis caused by C. trachomatis attacks which structure?
a. eye
b. urethra
c. fallopian tubes
d. all of these

16. A breath test is given to people who may have H. pylori. Urea is swallowed and on exhalation, what is given off if H. pylori is present?
a. radioactive O2
b. radioactive CO2
c. ammonium
d. urine

17. How are R. rickettsii and Lyme disease alike?
a. both are transmitted by ticks
b. both are more common on the western seaboard
c. both have a rash that occurs only on the chest
d. none of the above

18. Ship or Prison fever is another name for...
a. Chlamydia
b. Rocky Mountain spotted fever
c. Rickettsia typhi
d. Rickettsia prowazekii

19. Which of the following causes blindness in babies?
a. Campylobacter jejuni
b. Helicobacter pylori
c. Rickettsia prowazekii
d. Chlamydia trachomatis

20. Which of the following has no cell wall or shape?
a. Mycoplasma
b. Chlamydia
c. Rickettsia
d. Campylobacter jejuni

Ch. 21 Comprehension Questions

Characteristics of spirochetes
What does Treponema pallidum look like?
Characteristics of Treponema pallidum
What is the primary symptom of syphilis?
Where does syphilis’ primary symptom usually occur? What eventually happens to it?
What happens during secondary syphilis?
If left untreated, what happens after secondary syphilis?
What are the symptoms of tertiary syphilis?
Characteristics of congenital syphilis
Symptoms of congenital syphilis?
How is syphilis treated?
Famous or literary people with syphilis
U.S.’s dark history with syphilis
Characteristics of Leptospira
What is leptospirosis?
How does leptospirosis infection occur?
What are the principal targets of leptospirosis?
What are the symptoms of leptospirosis?
Long-term effects of leptospirosis?
Characteristics of Borrelia
Characteristics of Borrelia hermsii
Symptoms of relapsing fever
Why is it called relapsing fever?
How is relapsing fever treated and prevented?
Characteristics of Borrelia burgdorferi
Characteristics of Lyme disease
Treatment & prevention of Lyme disease? Vaccine available?
When and how was Lyme disease discovered?
Characteristics of Vibrio cholera
Characteristics of cholera
Treatment and prevention of cholera?
Vaccine available for cholera?
What is one way people in endemic regions prevent becoming infected by the water?
Cholera and the beginning of epidemiology
Characteristics of Helicobacter pylori
What virulence factor of H. pylori can lead to chronic active gastritis? How does this happen?
When and who discovered Helicobacter pylori?
What kind of person is more likely to develop an ulcer from Helicobacter?
How is H. pylori diagnosed?
Characteristics of Campylobacter jejuni
After C. jenuni is ingested, how does it infect the intestine?
Symptoms of C. jejuni?
Main virulence factor of C. jejuni?
Characteristics of Rickettsia
Where on the body is a common target in rickettsial infections?
Treatment of Rickettsia?
Characteristics of Rickettsia prowazekii
Who is Rickettsia prowazekii named after?
What are the symptoms of Rickettsia prowazekii?
Characteristics of Rickettsia typhi
Characterisics of Rickettsia rickettsia
Characteristics of Chlamydia
Characteristics of Chlamydia trachomatis
What are the two strains of Chlamydia trachomatis?
Characteristics of ocular trachoma
Characteristics of inclusion conjunctivitis
Characteristics of sexually transmitted chlamydial diseases

Ch. 21 Comprehension Answers

Gram-negative cell wall, periplasmic flagella, flexing and crawling motion, major pathogens are found in genera Treponema, Leptospira, and Borrelia
Has 8-20 evenly spaced coils. Very thin, doesn’t stain well, have to use dark-field microscopy to see it. Also can be seen with immunofluorescent staining.
Treponema pallidum: 1. Causes syphilis

Humans are the natural host – which means we could potentially eliminate it.
Extremely fastidious and sensitive, doesn’t survive long outside the host, doesn’t grow well in the lab.
Infectious dose is 57 cells, risk of infection from an infected sexual partner is 12-30%
Transmitted sexually, also through the placenta
Distinct clinical stages: primary, secondary, and tertiary syphilis. Communicable during the first two stages

4. After getting infected, the bacteria incubate from 9 days to 3 months with no symptoms, then a hard, painless chancre (sore) appears at the site of inoculation.
5. Most chancres appear on the internal and external genitalia, but about 20% occur on the lips, nipples, or fingers or around the anus. The chancre heals spontaneously in 3-6 weeks. 6. Secondary syphilis:

There is a latency period of 2-8 weeks before this time. Symptoms go away, but the spirochete is very busy invading many systems of the body.
The person has a fever and then breaks out in a full-body red or brown rash. Very infectious during this stage because the spirochetes are right on the surface.
The rash disappears spontaneously after a few weeks.

7. After resolution of secondary syphilis, the infection becomes latent for up to 20 years. The final stage of syphilis is rare today because of widespread use of antibiotics.
8. Tertiary syphilis symptoms include:

painful swollen gummas that develop in the liver, skin, bone, and cartilage;
neurosyphilis that can destroy the blood vessels in the brain, cranial nerves, and spinal cord nerves;
severe headaches & convulsions;
mental derangement;
atrophy of the optic nerve & blindness;
and the Argyll-Robertson pupil reaction (pupil doesn’t react to light).

9. Congenital syphilis:

Treponema pallidum can pass from a pregnant woman’s circulation into the placenta into the fetus.
Most common in the 2nd and 3rd trimesters.
Inhibits fetal growth and can cause spontaneous miscarriage or stillbirth

10. Infants have nasal discharge, skin eruptions and loss, bond deformation, nervous system abnormalities, and Hutchinson’s teeth (notched, barrel-shaped incisors).
11. Years ago it was treated with mercury, Paul Ehrlich developed Salvarsan for it in 1920 (toxic due to arsenic), now Penicillin G is the best choice. 12. Oscar Wilde’s “The Picture of Dorian Gray” and Charlotte Bronte’s “Jane Eyre” were said to have main characters with syphilis. Winston Churchill’s dad died on it when he was 45.
13. From 1932-1972 the U.S. government did a study on syphilis involving black men – they didn’t know they had the disease and weren’t given treatment for it. Called “Tuskegee Study of Untreated Syphilis in the Negro Male.”
14. Characteristics of Leptospira:

Typical spirochetes marked by tight, regular, individual coils with a bend or hook at one or both ends.

Its two species are L. biflexa (a harmless, free-living saprobe) and L. interrogans (a zoonotic bacteria that causes leptospirosis in humans and animals)

15. A zoonosis associated with wild animals such as rodents, skunks, raccoons, foxes, and some domesticated animals, particularly horses, dogs, cattle, and pigs. The disease is concentrated mainly in the tropics.
16. Infection occurs …

The bacteria is shed in the urine of an infected animal. It can survive for several months in soil or water.

Infection occurs almost entirely through contact of skin abrasions or mucous membranes with animal urine or some environmental source containing urine.

Not associated with animal bites, inhalation, or human contact. 50-60 cases/year in the U.S.

17. Principal targets are the kidneys, liver, brain, and eyes.
18. Symptoms are a sudden high fever, chills, headache, muscle aches, conjunctivitis, and vomiting. During the second phase, there’s a milder fever, headache due to leptospiral meningitis, and Weil’s syndrome, a cluster of symptoms characterized by kidney invasion, hepatic disease, jaundice, anemia, and neurological disturbances.
19. Causes long-term disability and death from injury to the kidneys and liver – primarily with virulent strains or in elderly patients
20. Characteristics of Borrelia:

Comparatively larger spirochete than the others, has 3-10 coils

Borrelioses are all transmitted by some type of arthropod vector, usually ticks or lice.

The two most important diseases are relapsing fever and Lyme disease.

21. Characteristics of Borrelia hermsii:

Causes relapsing fever

Carried by ticks, reservoirs are squirrels, chipmunks, and other wild rodents – humans are an accidental host.

The spirochetes mature and persist in the salivary glands and intestines of the tick.

Epidemics of louse-borne relapsing fever occur whenever famine, war, or natural disasters are coupled with poor hygiene, crowding, and inadequate medical attention (favors lice growth).

Louse-borne fever is most common in parts of China, Afghanistan, and Africa.

22. Symptoms of relapsing fever:
a. After a 2-to-15-day incubation period, patients experience an abrupt onset of high fever, shaking chills, headache, and fatigue. b. Grows into nausea, vomiting, muscle aches, and abdominal pain. c. Extensive damage to the liver, spleen, heart, kidneys, and cranial nerves occur in many cases.
23. The fever fluctuates as the spirochete changes and the immune system attempts to control it. Borrelia changes surfaces antigens during growth, so that, in time, the antibodies formed against the earlier antigens lose effectiveness. Cells with the new antigen survive, multiple, and cause a second wave of symptoms.
24. Treated by tetracycline and amoxicillin. Prevented by using insect repellant containing DEET, also controlling rodents and avoiding tick bites.
25. Characteristics of Borrelia burgdorferi:

Transmitted by ticks

Infected ticks pass through a complex 2-year cycle that involves feeding on mice first as a larva, then feeding on deer as an adult.

Causes Lyme disease, which is the most prominent borreliosis in the U.S.

26. Characteristics of Lyme disease:

Nonfatal, slowly progressive syndrome that mimics neuromuscular and rheumatoid conditions.

50-70% of cases get a bull’s-eye rash at the site of the tick bite.

Early symptoms are fever, headache, stiff neck, and dizziness.

If untreated, it can advance to the second stage, where cardiac and neurological symptoms develop, as well as polyarthritis.

27. Treatment is tetracycline and amoxyclline. Prevention by using insect repellant containing DEET, also wearing long pants and long-sleeved shirt while in the woods. A vaccine for dogs is available, human vaccine discontinued.
28. Lyme disease was discovered in the 1970s in Old Lyme, Connecticut, when Polly Murray was beset for years with it and discovered 30 of her neighbors were too. She investigated more after her son was diagnosed with juvenile rheumatoid arthritis and she became skeptical. 29. Characteristics of Vibrio cholerae:

Causes cholera
Comma-shaped cells with a single polar flagellum
Possesses unique O (somatic) antigens and H (flagella) antigens
10-to–the-8th power infectious dose

30. Characteristics of cholera:

One of the top seven causes of morbidity and mortality in the world.
Warm, monsoon conditions favor outbreaks of cholera.
Ingested with food or water; travels through the stomach and infects the surface of the small intestine – noninvasive, does NOT enter cells or deeper tissues.
The virulence is due to an enterotoxin called cholera toxin that disrupts the normal physiology of intestinal cells. The toxin causes cells to shed large amounts of electrolytes, accompanied with profuse water loss through secretory diarrhea.
Results in watery diarrhea called “rice-water stool”, and dehydration that leads to muscle, circulatory and neurological damage

31. Treatment of cholera is oral rehydration (replace water and electrolytes) and tetracycline. Prevention includes proper sewage disposal and water purification. 32. A vaccine containing live, attenuated vibrios is available for travelers and people living in endemic regions. 33. People in endemic regions will fold a blanket eight times and run their water through it as a filtration system. 34. In 1936, a doctor named John Snow mapped out cases of cholera in London. He traced the cases back to a single water pump called the Broad Street Pump. This was the beginning of epidemiology. 35. Characteristics of Helicobacter pylori:

Its primary habitat is the acidic environment of the stomach.

Curved cells with a multiple sheathed polar flagella – NOT a spirochete.

Causes 90% of stomach and duodenal ulcers.

36. H. pylori produces large amounts of urease, which can neutralize stomach acid. As the immune system attacks the pathogen, certain white blood cells damage the epithelium to some degree, leading to chronic active gastritis. 37. Discovered in 1979 by Dr. J. Robin Warren – he and an assistant swallowed an inoculum and developed a short-term case of gastritis. They were awarded a Nobel Prize in 2005. 38. People with type-O blood have a 1.5-2X higher rate of ulcers – one receptor specific for Helicobacter is the same receptor as type-O blood. 39. H. pylori gives off large amounts of urease and can be initially identified with a test that detects pH changes. Also a urea breath test can also be used – involves swallowing urea that gives off radioactive CO2 in exhaled air if H. pylori is present. 40. Characteristics of Campylobacter jejuni:

Considered one of the most important causes of bacterial gastroenteritis (food poisoning) worldwide.

Primary pathogen transmitted through contaminated beverages and food, especially water, milk, meat, and chicken.

41. Ingested cells travel to the mucosa at the last segment of the small intestine (ileum) near its junction with the colon. They adhere, burrow through the mucus, and are taken in by the intestinal cells where they multiply. 42. After an incubation period of 1-7 days, symptoms of fever, headache, abdominal pain, and bloody or watery diarrhea develop (i.e. food poisoning).

Most people recover within a week.

An occasional sequela of this infection is the neurological disease called Guillain-Barre syndrome.

43. C. jejuni produces a heat-labile (if you heat up the food, you’ll kill the toxin) enterotoxin called CJT that stimulates secretory diarrhea like cholera. 44. Characteristics of Rickettsia:

All obligate to their host cells and require live cells for cultivation – obligate intracellular parasites (can’t live outside a cell)

Gram-negative cell wall

Spend part of their life cycle in the bodies of arthropods (ticks, fleas, and lice), which serve as vectors

Among the smallest bacteria – not much bigger than a virus

Nonmotile pleomorphic rods or coccobacilli (no flagella, no distinct shape)

45. A common target in rickettsial infections is the endothelial lining of the small blood vessels. The bacteria enter and multiply within endothelial cells, causing necrosis of the vascular lining, which leads to vasculitis, vascular leakage, and thrombosis. 46. Treated with tetracycline and chloramphenicol. 47. Characteristics of Rickettsia prowazekii:

Humans are the sole hosts of human body lice and the only reservoirs of R. prowazekii.

Causes epidemic typhus.

48. Named after Dr. Howard Ricketts and Stanislas von Prowazek, who discovered it in the early 1900s. They investigated it, then both died from it.
49. First symptoms are high fever, chills, headache, muscular pain. Within 7 days, a generalized rash appears. After several years a chronic, recurring form of the disease, known as Brill-Zinsser disease, can appear.

First symptoms are high fever, chills, headache, muscular pain. Within 7 days, a generalized rash appears. After several years a chronic, recurring form of the disease, known as Brill-Zinsser disease, can appear.

50. Characteristics of Rickettsia typhi:

Causes endemic typhus.
Occurs sporadically in areas of high flea infestation.
Harbored by mice and rats.
Transmission to humans is chiefly through infected rat fleas that inoculate the skin.
Anne Frank died of typhus two weeks before the war ended.

51. Rickettsia rickettsii:

Causes Rocky Mountain Spotted Fever - the rickettsial disease with greatest impact on people living in North America.
Zoonosis carried by dog and wood ticks.
Most cases occur in the eastern seaboard states in spring and summer, when the tick vector is most active.
Causes a distinct spotted rash over most of the body, can lead to damage of the heart and central nervous system.

52. Characteristics of Chlamydia: a. obligate intracellular parasites b. Small gram-negative cell wall c. Chlamydias alternate between two stages: 1) a metabolically inactive, infectious form called the elementary body that is released by the host cell, and 2) a noninfectious, actively dividing reticulate body that grows within host cell vacuoles. 53. Characteristics of Chlamydia trachomatis: a. Human reservoir b. Two strains – Trachoma strain and Phogranuloma venereum d. Disease is most severe in infants and children. e. Babies can get it while passing through the birth canal. f. The leading cause of blindness worldwide. 54. The two strains of Chlamydia trachomatis: a. Trachoma strain – attacks the mucous membranes of the eyes, genitourinary tract and lungs. Causes ocular trachoma, inclusion conjunctivitis, and the STD. b. Phogranuloma venereum – invades the lymphatic tissues of the genitalia, causes a disfiguring disease of the external genitalia and pelvic lymphatics. 55. Characteristics of ocular trachoma: a. Causes an early, pebble-like inflammation of the conjunctiva and inner eyelid b. Antibiotics taken early on can prevent all complications – especially blindness. c. Caused by Chlamydia trachomatis 56. Characteristics of inclusion conjunctivitis: a. Babies get it while passing through an infected birth canal. b. Routine eye prophylaxis is given to all newborns in the U.S. 57. Characteristics of sexually transmitted chlamydial diseases: a. It’s estimated up to 10% of the population has it. b. About 70% of women are asymptomatic and 10% of men. c. Reportable disease since 1995. d. Chlamydia is the 2nd most prevalent STD. e. A particularly virulent strain result in a severe, disfiguring disease called lymphogranuloma venereum.

Nasty Gram Negative Bacilli

flattail — Tue, 23 Jun 2009 16:13:39 CDT

The Gram-Negative Bacilli of Medical Importance

Chapter Objectives:

Learn the Aerobic Gram-Negative Nonenteric Bacilli
- Pseudomonas
Learn the related Gram-Negative Aerobic Rods
- Brucella, Francisella tularensis, Bordetella pertussis, Legionella pneumophilia
Identification and Differential Characteristics of Family Enterobacteriaceae Enterotoxins, Coliforms, Noncoliforms

Coliform Organisms and Diseases
- Escherichia coli, Klebsiella
Noncoliform Lactose-Negative Enterics
- Proteus, Morganella, Providencia, Salmonella, Shigella, Yersinia, Pasteurella multocida, Haemophilus influenzae

Endotoxin Shock
Gram negative bacteria cell wall:The adverse factor in gram-negative sepsis is the presence of an endotoxin called lipopolysaccharide (when released is a side effect of cell death. It is a pyrogenic and immune stimulating, it is also considered an endotoxin), in the outer membrane of the cell wall. Lipopolysaccharide is a potent immune stimulator. The component that accounts for the most of the adverse effects is lipid A embedded in the external layer of the membrane. This lipid A is activated only after it is liberated by bacteria that are growing or lysed by host defenses and other factors. In general, lipid A triggers the secretion of interleukins, tumor necrosis factor, and other cytokines by Macrophages. Sepsis leads to large release of LPS, and macrophages release cytokines, which cause fever, and low blood pressure, which can in turn cause organ and tissue damage.
Sepsis Symptoms: Nausea, tachycardia, low blood pressure, and fever. Can progress to respiratory failure, coma, heart failure and death. Antibiotics can compound the effects, they can cause the release of more LPS. Resistant to most antibiotics.

Gram-Negative Diseases
Bacteremia(septicemia)-is the proliferation of microorganisms in the blood. The gram-negative bacteria involved are E. Coli, Serratia marcescens, Proteus mirabilis, Enterobacter aerogenes, and Pseudomomas aeruginosa. Symptoms are produced by the endotoxins that are released from bacterial cell walls. The endotoxins eventually cause vasodilation, hypoxia and subsequent cardiovascular shock.

Aerobic Gram-Negative Bacilli
-Pseudomonas-an opportunistic pathogen
-Brucella-zoonotic pathogens
-Bordetella pertussis and Legionella-mainly human pathogens
-Alcaligenes-opportunistic pathogens

Q: What virulence factor is common to all Gram negative bacilli?
a. Capsule
b. Exotoxin
c. Endotoxin
A: Endotoxin

Q: What is the cardinal manifestation of human brucellosis?
a. Vomiting and diarrhea
b. A fluctuating pattern of fever
c. A cough that lasts for months
A: A fluctuating pattern of fever

Pseudomonas aeruginosa

Pseudomonas are a large group of free-living bacteria. They live in soil and sea/fresh water (they use H2O). They also colonize in plants and animals and are frequently found in homes (and flowers at hospitals!). They are small, gram-negative rods that have a single flagellum.

Pseudomonas aeruginosa is an intestinal resident in 10 % of normal people. It is resistant to soaps, dyes, quaternary ammonium disinfectants, drugs and drying (living and metabolizing inside or on). Pseudomonas aeruginosa is a frequent contaminant (they colonized inside) of ventilators, IV solutions, and anesthesia equipment.

Pseudomonas aeruginosa is a common cause of nosocomial infections in hosts with burns, neoplastic disease, and cystic fibrosis. Complications include pneumonia, UTIs, abscesses, otitis, corneal infections, endocarditis, meningitis, and bronchopneumonia.

Pseudomonas aeruginosa is a typical opportunist pathogen (lives in food). It is unlikely to infect a healthy person, thus it's infectiousness usually results from invasive medical procedures or weakened host defenses. Once in the tissues, P. aeruginosa expresses virulence factors including exotoxins, a phagocytosis-resistant slime layer, and various enzymes that degrade host tissues. It also causes endotoxic shock.

Pseudomonas aeruginosa has a grape-like odor, and is greenish-blue in color (pyocyanin). It glows under UV light. Areas infected with P. aeruginosa may appear green due to growth of this pathogen (in the nails). Also, you should not use your mascara too long because this bacteria may form inside the tube.

It is multi-drug resistant, but cephalosporins, aminoglycosides, carbenicillin, polymixin, quinolones, and monobactams can all work.

Of the above antibiotics, only fluoroquinolones can be taken orally. An example is Cipro. Antibiotics are used sparingly in hopes of avoiding development of resistant strains. Most people have IV antibiotics if you have Pseudomonas aeruginosa.

Pseudomonas aeruginosa are an opportunist pathogen, and the most common organism on the planet. They typically like to infect some one with burns, cuts, cystic fibrosis, or indwelling catheter. Sine they are multi-drug resistant it makes sensitivity testing imperative, however, vaccine are being tested for cystic fibrosis patients.

Other Gram-Negative Aerobic Rods

Burkholderia cepacia (don't need to know this one for class)

Burkholderia cepacia is a common isolate from moist environments that plays an important ecological role in controlling fungal disease on plants. It is active in biodegradation of a variety of toxic substances. It also has a potential for opportunistic infections in the respiratory tract, urinary tract, and the skin. Pneumonia caused by B. cepacia holds risks for cystic fibrosis patients, whose disease creates conditions that can favor the entrenchment of pathogens in the lungs.

Finding a successful treatment is a challenge because of its tendency to mutate rapidly and resist antimicrobic drugs. Co-infection with Pseudomonas may lead to severe respiratory compromise and death in 80% of patients.

-Cystic fibrosis patients suffer from a lung condition where mucus collects and creates a protective biofilm tenaciously colonized by pseudomonas.

Burkholderia pseudomallei (don't need to know this one for class)

Burkholderia pseudomallei resides in the soil and water of tropical climates. It causes melioidosis, which is prevalent in many areas of Southeast Asia and parts of Africa, India, and the Middle East.

It is generally acquired through a penetrating injury by a soiled object or inhalation from environmental reservoirs rather than from an infected person. Manifestations of wound infection are localized skin nodules along with symptoms of fever and muscle aches. Lung infection gives rise to bronchitis and pneumonia that is attended by cough and chest pain. Chronic infection may progress to septicemia, endotoxic shock, and abscessed in organs such as the liver and the brain. In persons with compromised immune systems, the infection can cause severe disseminated disease that is occasionally fatal.

Acinetobacter baumanii (don't need to know this one for class)

Acinetobacter baumanii is distributed throughout the world and has recently become a high-profile pathogen in nosocomial and community-acquired infections. It is an extremely resistant bacterium known to survive for months on inanimate objects such as faucets, toilets, bed cloths, doorknobs, sinks, respiratory equipment, and catheters.

It can cause severe infections in wounds, lungs, the urinary tract, burns, and blood. It is been one of the more problematic agents of wound infections seen in military personnel with traumatic injuries in Iraq and Afghanistan. Combat conditions make control and treatment more difficult and increase the risk for bloodstream infections. Another complication is the new occurrence of multidrug-resistant strains that are able to withstand the usual broad-spectrum drugs.

Most infections can be treated with some combination of carbapenems, colistin, polymyxin B, and ampicillin.

Stenotrophomonas maltophilia (don't need to know this one for class)

Stenotrophomonas maltophilia has unique genetic sequences and the presence of unusual fatty acids that prompted its reclassification into this new genus and species. The natural habitat of this bacterium is fresh water and soil associated with plant roots. It is also a member of fecal flora in humans and may be isolated from domestic animals.

It appears in the clinical setting as a contaminant of disinfectants, dialysis equipment, respiratory equipment, water dispensers, and catheters.

It has an ability to lay down biofilms, which protect it against drugs and disinfectants. It is a prominent clinical isolate as well, and is most often found in respiratory soft tissue, blood, spinal fluid, and ophthalmic specimens. Higher rates of infection occur in cancer patients and people with tracheostomies and other indwelling invasive devices.

Although the species is one of the most drug-resistant of bacteria, therapy with a combination of cephalosporins, tetracyclines, fluoroquinolones, or new penicillins are usually effective.

Brucella/Brucellosis

Bruccellosis in Cattle: this disease is also known as "contagious abortion"or "Bangs disease", it is caused by infection by the bacteria Brucella Abortus. This disease causes premature calving or abortion of cattle. Milk produced by the cow my also carry the organism. There is NO treatment!!!

Brucellosis- which causes undulant fever that can last for weeks or months. They are tiny gram negative, aerobic, nonenteric(not usually in stool sample), zoonotic pathogens that may cause fluctuating pattern of fever, chills, sweating aches and fatigue.
Brucella are tiny gram-negative coccobacilli. There are two species...brucella abortus which is common in cattle, and Brucella suis, which is found in pigs. It is associated mostly with those who work in slaughterhouses, work with livestock, or are in the veterinary business.

Infection takes place through contact with the animal's blood, urine, placenta, or the consumption of raw milk or cheese. Brucellosis, malta fever, undulant fever and Bang disease (a zoonosis transmitted to humans from infected animals), fluctuating pattern of fever for weeks to a year. Treatment for brucella is a combination of tetracycline and rifampin or streptomycin. Vaccines for animals are available, but those developed for humans are ineffective or unsafe. Because of this, Brucella could potentially be used as a germ warfare agent.

Q: Brucellosis is spread to humans by human contact with all but which of the following?
a. Blood
b. Urine
c. Cerebrospinal fluid
A: Cerebrospinal fluid

Q: What is the cardinal manifestation of human brucellosis?
a. Vomiting and diarrhea
b.

A fluctuating pattern of fever

Bordetella pertussis

Pertussis: infection by bordetella pertussis, a highly communicable disease that causes acute respiratory syndrome. Can be life-threatening in infants, but vaccines on the recommended schedule can prevent it. ALSO CALLED WHOOPING COUGH

A minute, encapsulated coccobacillus that causes pertussis or whooping cough, a communicable childhood affliction. It causes acute respiratory syndrome and often severe and life-threatening complications occur in infants under the age of one. There is an upsurge in infections due to worry over the vaccine, due to a possible correlation with autism. The old, whole cell vaccine contained thimerosal, which contains mercury. The new acellular vaccine dose not contain mercury. There is also a booster for teens called Boostrix.

Transmission of bordetella pertussis is by direct contact or inhalation of aerosols. There are 30-50 million cases per year and about 300,000 deaths per year (World Health Organization data). Most deaths occur in children under one year of age. Ninety percent of all cases occur in developing countries. Immunity and vaccine only last a few years.

Bordetella pertussis virulence factors: receptors that recognize and bind to ciliated respiratory epithelial cells. Then toxins destroy and dislodge ciliated cells leading to loss of ciliary mechanism which causes build-up of mucus and blockage of the airways.

The initial phase of pertussis is the catarral stage, marked by nasal drainage, sneezing and cough. As the condition worsens, it enters into the paroxysmal stage where the patient, the child ,experiences recurrent, persistent coughing. The coughs are fits of several abrupt, hacking coughs, followed by a deep inhalation that produces the "whoop" noise.

The vaccine-DTap acellular vaccine contains toxoid and other Ags. This vaccine is given at 2 months, 4 months, 6 months, 12 months and then a booster is given prior to admission to elementary school usually around age 5. Due to the change in disease epidemiology, it is clear that booster doses are necessary--however, older children and adults are not good candidates for the acellular pertussis (aP) vaccine. In response, the CDC has added a new vaccine--Boostrix--recommended just for older children and adolescents age 10-18, that is a combination of diphtheria, tetanus, and pertussis antigen.

These are sounds that no parent wants to hear coming from their child.

www.medscape.com/viewarticle/574587: (guidlines for Tdap vaccines during pregnancy)

Tdap may be substituted for Td during pregnancy if immunization cannot be delayed during pregnancy or when the risk of pertussis is increased.

In such cases, women should be informed of lack of data on safety, immunogenicity, and pregnancy outcomes for pregnant women who received Tdap.

If Tdap is administered during pregnancy, the second or third trimester is preferred unless protection is urgently needed.

E. Coli and the Coliform Count

because if its prominence as a normal intestinal bacterium in most humans, E coli is currently on of the indicator of the bacterial to monitor fecal contamination in water, food, and dairy products.

coliforms such as E coli are used because they are present in larger numbers, can survive in the environment, and are easier and faster to detect than true pathogens.

if a certain number of coliforms are detected in a sample. the water is judged unsafe to drink
When they are testing for E-coli, they specifically test for O157:H7. The primary way to rapidly identify it is with selective media in the lab. Testing is performed randomly, and is not required by slaughterhouses and meat suppliers, but it has been successful in identifying pathogens in meats and the recall of millions of pounds of hamburger.
Other Coliforms (Lactose + Enterics)

Klebsiella pneumonia: Often a normal inhabitant of the respiratory tract, Klebsiella has a large capsule which promotes infection by preventing phagocytosis. Klebsiella pneumonia causes pneumonia, meningitis, bacteremia, wound infections and UTIs.

Serratia marcescens-produces a red pigment when grown at room temp. Serratia causes pneumonia, burn and wound infections, septicemia, and meningitis. Interestingly enough this bacteria was once thought so benign that they used it to trace the movements of air currents in hospitals and over cities and even to demonstrate transient bacteremia after dental extraction. Unfortunately, it is fully capable of invading compromised host.

The 2004 flu vaccine was recalled due to contamination with Serratia.

Noncoliforms (Lactose-negative enterics)
Proteus-An opportunist that swarms on surface of moist agar in a cocentric pattern. Can cause UTIs, wound infections, pneumonia, septicemia, and infant diarrhea. Proteus UTIs stimulate renal stones and damage.

Salmonella-
Salmonella is a true enteric pathogen. Salmonella is motile, it ferments glucose and is resistant to chemicals,spore forming, bile and dyes. Salmonella are flagellated and grow readily on most lab media. They also are able to survive outside the host in environments such as fresh water and freezing temps. Along with Shigella, salmonellae have well-developed virulence factors and are not part of the normal flora in humans. The illnesses they cause slow GI involvement and cause diarrhea, but often affect other systems as well.

The most serious of the salmonella genus is S. thyphi (Thyphoid Fever). It enters the digestive system through water or food contaminated by feces, but can occasionally be spread through close personal contact. The ingested bacilli that adhere to the small intestine and cause invasive diarrhea that leads to septicemia. Various Salmonella species can cause gastroenteritis in 2-5 days. ( I don't recommend feeding the seals at the Seaside aquarium in Oregon.)

Salmonelloses other than typhoid fever are called enterc febers, salmonella food poisoning, and gastroenteritis. These diseases are usually less severe. They are more prevalent than typhoid fever, and unlike typoid, all strains are zoonotic in origin. Salmonella are normal intestinal flora in cattle, poultry, rodents and reptiles. Animal products can be easily contaminated during slaughter, collection or processing. Eggs are another problem, since the bacteria may actually enter the egg while the shell is being formed.

MARY MALLON (aka Typhoid Mary)
At one time was dubbed "the most dangerous woman in America" Over the course of her career as a cook, she infected 47 people, three of whom died from the disease. Her fame is in part due to her vehement denial of her own role in causing the disease, together with her refusal to cease working as a cook. She was forcibly quarantined twice by public health authorities and died in quarantine. It was also possible she was born with the disease, as her mother had typhoid fever during her pregnancy.

Shigella-
Shigella is a genus of Gram-negative, non-spore forming rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella cause disease in primates, but not in other mammals. Shigella causes a common but often incapacitating dysentery known as shigellosis. Shigellosis produces H2S or urease, invades the villus of the large intestine. This enters the Peyer's patches, instigates inflammatory response and then endotoxins and exotoxins are released.

Shigellosis is acquired primarily by eating fecal-contaminated foods. It can also be transferred by human-to-human contact because it requires a small dose to be infected (100-200 cells).

Shigellosis is different from salmonellosis in that Shigella invades the villus cells of the large intestine, rather than the small intestine. In addition, it can possibly perforate the intestine or invade the blood. It is a very invasive infection that causes bloody diarrhea. S. dysenteria produces heat-labile exotoxin that has a number of effects, including injury to nerve cells and nerves, and damage to the intestine. The most common symptoms are diarrhea, fever, nausea, vomiting, stomach cramps, flatulence, and straining to have a bowel movement. The stool may contain blood, mucus, or pus.

Treatment is fluid replacement and ciprofloxacin (a fluoroquinolone) and sulfa-trimethoprim. No vaccine is yet available.

Yersinia Pestis-

Yersinia pestis is nonenteric. They are tiny gram-negative rods with unusual bipolar staining and capsules. The virulence factors are their capsule and envelope, proteins protect against phagocytosis and foster intracellular growth. The bacillus also produce coagulase which clogs the esophagus in fleas and obstructs blood vessels in humans. Other factors that contribute to pathogenicity are endotoxin and a highly potent Murine toxin. the word plague conjures up death and morbidity unlike any other infections disease. Although pandemics of plague have probably occured since antiquity, the first one that was reliability chronicled killed an estimated 100 million people in the sixth century. the last great pandemic occured in the late 1800's and was transmitted around the world, primarily by rat-infested ships. The disease was brought to the US through the port of san Franciscoaround 1906. Eventually, infected rats mingles with the native populations of rodents and gradually spread the populations throughout the West and Midwest. The cause of this dread disease is a tiny, harmless-looking gram-negative rod called Yersinal Pestis formerly pasteurella pastis, with unusual bipolar staining and capsules

The plague bacillus exists naturally in many animal hosts. In the US, humans develop the plague through direct contact with wild animals (sylvatic plague) or domestic or semidomestic animals (urban plague) or infected humans. This is found in 200 species of mammals (rodents) without causing disease. Flea vectors are where the bacteria replicates in the gut, coagulase which causes blood clotting that blocks the esophagus; flea becomes ravenous. No human-to-human transmission of the plague has been noted since 1924. Recently Y. pestis has gained attention as a possible biological warfare agent and the CDC has classified it as category A pathogen requiring preparation for a possible terrorist attack. Y. pestis may be afflicting al-qaeda in Algeria.

Pathology of the Plague

3-50 bacilli
The bubonic plague-bacillus multiplies in flea bites, enters the lymphatic system and is stopped at lymph nodes, the infection causes necrosis and swelling called bubo.
Septicemia-progression to massive bacterial growth; virulence factors cause intra-vascular coagulation subcutaneous hemorrhage and purpura (Black plague)
Pneumonia-infection localized to the lungs, highly contagious; fatal without treatment
Treatment: streptomycin, tetracycline, or chloramphenicol

Hemophilus

Tiny gram negative pleomorphic rods. Fastidious, sensitive to drying, temperature that are extreme, and disinfectants. None can grow on blood agar without special techniques, such as chocolate agar. Require hemin, NAD or NADP. Some species are normal colonists of upper respiratory tract or vagina ( H. aegyptius, H. parainfluenza, H ducreyl). Other are virulent species responsible for conjunctivitis, childhood meningitis, and chancroid. People thought it was the cause of the Flu but it really was not.

H. influenzae, is acute bacterial meningitis, epiglottitis, otitis media, pneumonia, and bronchitis(subunit vaccine Hub). H. aegyptius-conjunctivitis, which is pink eye. H. durcreyi-chancroid STD. H. parianfluenzae and H. aphrophilus-normal oral and nasopharngeal flora, infective endocarditis.

Hemophilus aegyptius (Koch-Weeks bacillus)
-Is an agent of communicable conjuctivitis (pinkeye).
-The subconjuctival hemorrhage that accompanies infection imparts a bright pink tinge to the sclera.
-Occurs primarily in children.
-It is distributed worldwide.
-It is spread through contaminated fingers and shared personal items as well as mechanically by gnats and flies.
-Is treated with antibiotic eye drops.

Flash cards for this chapter on www.flashcardexchange.com under Kevin Youngs micro chapter 20

Identifying Gram Negative Bacilli-

IMViC tests- Is used to identify enterics (such as: Klebsiella, Enterobacter, and Escherichia coli). An INViC test can tell the difference between these bacteria. IMViC stands for indole, methyl red, Voges- Proskauer and Citrate.

Indole test- The test organism is inoculated into tryptone broth (a source of tryptophan- an amino acid). An Indole positive bacteria will cleave to tryptophan and produce tryptophanase. When Kovac's reagent is added to a broth with indole in it the solution turns dark pink. It must be read by 48 hrs. of incubation. The acid pH of E. coli can limit its growth.

Methyl Red and Voges-Proskauer tests- The methyl red and Voges-Proskauer tests start with a single tube of broth which is inoculated. After 24-48 hours, the tube is split into two. Use one tube for the methyl red test and the other for the Voges-Proskauer test. The media for this test has glucose and peptone. All enterics digest glucose but they have different ending enzymes. These tests determine the ending enzymes for the bacteria being tested. If the pH drops (like when testing E.coli) and the pH indicator methyl red is added to the broth it becomes red.
Klebsiella and Enterobacter produce neutral products with the bacteria is not inhibited so it attacks the peptone found in the broth. This causes the pH to rise and the methyl red indicator to turn the broth yellow.
The reagents for the Voges-Proskauer test is the Barritt's A and Barritt's B reagents. If acetyl methyl carbinol is present in the broth it turns a pink color within 20-30 min. E. coli won't produce acetyl methyl carbinol. However, Enterobacter and Klebsiella will.

Citrate test- This tests determines if bacteria can grow utilizing citrate as its sole carbon and energy source by using Simmon's media. If the bacteria is citrate positive it will be blue, but if the bacteria is citrate negative the broth will be green. Enterobacter and Klebsiella are citrate positive and E. coli is negative.

Oxidase test- This tests a bacteria's ability to produce the enzyme cytochome c oxidase. Pseudomonas aeruginosa, Neisseria gonorrhoeae and Campylobacter jejuni are oxidase-positive. During the cellular respiration of these bacteria oxidation reduction reactions are done until it reaches the final electron acceptor (often oxygen).

Questions: Q&A Page~~Home Page~~Top of Page

1. A classic symptom of pertussis is
a. labored breathing
b. paroxysmal coughing
c. convulsions
d. headache

2. The bubo of bubonic plague is a/an
a. ulcer where the flea bite occurred
b. granuloma in the skin
c. enlarged lymph node
d. infected sebaceous gland

3. Which of the following represents a major difference between Salmonella and Shigella infections?
a. mode of transmission
b. likelihood of septicemia
c. the portal of entry
d. presence/absence of fever and diarrhea

4. Which gram negative disease can you be a carrier of and have no signs of the disease?
a. Shigella
b. Typhoid
c. Yersinia pestis
d. Serratia

5. This bacteria was the cause of the recall on the 2004 flu vaccine.
a. Serratia marcescens
b. Proteus
c. E. coli 0157:H7
d. Klebsiella pneumoniae

6. This opportunistic bacteria will swarm on the surface of moist agar in certain intervals and produce patterns of rings (wave-like patterns) due to their motility.
a. Serratia marcescens
b. Klebsiella pneumonae
c. Proteus
d. Shigella

7. This type of bacteria has acquired the gene for shiga toxin from Shigella. The toxin enters the host cell, binds to ribosomes, and disrupts protein synthesis, leading to death and shedding of intestinal cells.
a. E-coli O157:H7
b. Citrobacter
c. Serratia
d. Providencia

8. Noncoliform opportunists include all of the following except
a. Proteus
b. Morganella
c. Serratia
d. Providencia

9. Infection that imparts a bright pink tinge to the sclera is a result of which of the following?
a. Haemophilus aegyptius
b. Haemophilus chancroid
c. Pasteurella multocida
d. Typhoid fever

10. Which of the following is the bacteria that is the majority of nosocomial infections?
a. Salmonella
b. Klebsiella
c. Escherichia coli
d. Enterobacter

11. A unique characteristic of many isolates of Pseudomonas useful in identification is_____
a. fecal odor
b. fluorescent green pigment
c. drug resistance
d. motility

12. Complications of typhoid fever are________
a. neurological damage
b. intestinal perforation
c. liver abscesses
d. b and c

13. For the past several weeks, Josh has been suffering from chills, profuse sweating, and headaches. He works in a small-town veterinary clinic that specializes in treating farm animals. What species has he probably been infected with?

14. Jebediah recently traveled to Mexico. After drinking the tap water there, he became sick with diarrhea, fever, and vomiting. What species has he most likely been infected with?

15. Just in case you were tempted to do so … don’t eat foods contaminated by rodent feces! They may carry this pathogenic species, which is also associated with poorly cooked beef, unpasteurized fresh milk, homemade ice cream made with raw eggs, and Caesar salad. What is it?

16. Jack works as a janitor at the local hospital. His main duty is to clean the bathrooms, including disinfect the sinks and soap dishes and mop the floors. What contaminant may he come into contact with from the bathroom fixtures, the soap dishes, and the mop?

17. Almost all cases of this infection occur in developing countries, especially in babies under one year old. What infection is it?

18. Joe is a 60-year-old male who works as a produce manager at the local grocery store. As part of his job he regularly sprays down the fruits and vegetables in the produce section. Recently he’s been out sick with a rising fever, cough, diarrhea, and abdominal pain. What species may he have been infected with?

19. This opportunistic pathogen forms a mucus-y and stringy colony due to its thick capsule. It’s a normal inhabitant of respiratory tract, and a frequent cause of nosocomial pneumonia. What is it?

20. This species is not highly invasive, and is rather an opportunistic pathogen. That’s why it likes to prey on people having invasive medical procedures, and grows biofilms on ventilators, IVs, and anesthesia equipment. What is it?

21. Jeremiah’s favorite food is a big, juicy hamburger. He cooks himself one every day. Yesterday he forgot to wash his hands after handling the meat. He cooked his burger, ate it, then licked his fingers hungrily to enjoy the taste there, too. Today he’s been experiencing a high fever, watery diarrhea and severe cramps. What species has he likely been infected with?

22. This bacteria can enter through damaged skin or mucous membranes of the digestive tract, conjunctiva, and respiratory tract. It manifests itself in a fluctuating pattern of fever, giving the illness its common name, undulant fever. What species is it?

23. This species loves moist environments, such as sponges, washcloths, contact lenses, and mascara wands. What is it?

24. The likelihood of being infected by this species may be lessened by chlorinating drinking water and regularly cleaning swimming pools and other artificial aquatic habitats. What species is it?

25. Jackie has a urinary tract infection that has progressed to kidney stones. Her doctor sent a urine specimen to the lab, where a culture of it produced rings in a distinct concentric pattern. What species caused her UTI and kidney stones?

26. This species is used as an indicator of fecal contamination in water, food, and dairy products. The rationale is that if this species is present, then fecal pathogens like Salmonella, viruses, or even pathogenic protozoa may also be present. What species is it?

27. Which species doesn’t belong in this group: Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Proteus?

28. Joni is a six-year-old girl who has caught a case of conjunctivitis, which has caused redness in her sclera. Her doctor prescribed her with antibiotics drops to place in the infected area. What is the common name of her illness, and what species has she been infected with?

29. The vaccine for this gram-negative species is administered in a five-dose series with the DT vaccine. What species is it?

30. This disease causes 25,000 deaths/year worldwide. Humans are its exclusive hosts, and asymptomatic carriers are important in spreading the disease. Even six weeks after convalescence, the bacillus is still shed by half of recovered patients. A woman named Mary, who worked as a cook in New York in the early 1900s, was one such asymptomatic carrier. What is the disease, and what species causes it?

31. Along with cholera and yellow fever, what disease is one of the internationally quarantinable diseases?

32. On a selective medium called rainbow agar, this strain produces black colonies, while other strains of the same species do not. What species is it?

33. Jason is an alcoholic and was hospitalized recently for a liver transplant. The day after the surgery, the nurse noticed an intense red pigment discoloring some of Jason’s ventilator tube. What enteric species is he in danger of being infected by?

34. Which of the following is mis-matched:
a. Pseudomonas aeruginosa - contaminates IVs and ventilators
b. Bordetella pertussis - transmitted through inhaled droplets or aerosols
c. Legionella pneumophilia - transmitted through eating fecally contaminated foods
d. E. coli O157:H7 - most likely found in raw hamburger

35. Characteristics of this opportunistic pathogen species include a single polar flagellum, a grape-like odor, and a greenish-blue pigment that glows under UV light. What is it?

36. Both Janet and Jonathan had bladder catheters put in during a hospital visit. Which of them is more likely to develop a urinary tract infection, and what gram-negative species is most likely to cause it?

37. Which of the following ways can humans NOT be infected with the plague?
a. By handling animal skins that carry the plague bacillus
b. Through sexual contact with a person infected with the plague
c. Through bites from infected human fleas
d. By inhaling droplets transmitted by an infected person
e. By handling infected animals

38. Which of the following doesn't belong in this group: Serratia marcescens, Escherichia coli, Klebsiella pneumoniae, Salmonella, and Enterobacter?

39. This disease differs form salmonellosis in that it invades the large intestine rather than the small intestine. It causes an incapacitating dysentery marked by crippling abdominal cramps and frequent defecation of watery stool filled with mucus and blood. The small infectious dose of 100-200 cells is acquired primarily by eating fecally contaminated foods. What disease is it?

40. Which of the following pathogenic strains of Escherichia coli is mis-matched?
a. Enterotoxigen E. coli - has fimbriae to provide adhesion to the small intestine
b. Enteroinvasive E. coli - causes invasion and ulceration of the mucosa of the small intestine
c. Enteropathigenic E. coli - wasting form of infantile diarrhea
d. E. coli O157:H7 - causes hemorrhage that leads to kidney damage

41. Although the name of this bacteria means "blood-loving," it can't grow on blood agar alone, rather it needs chocolate agar and Fildes medium. What is it?

42. What species doesn't belong in this group: Bordetella pertussis, Escherichia coli, Haemophilus influenzae, Salmonella typhi, and Yersinia pestis?

43. Cultivation of this species requires special media such as charcoal agar, where feathery growth is indicative of its motility. What is the species?

44. When a plague epidemic occurs, which of the following strategies is NOT used to control infection?
a. Quarantining infected individuals
b. Making the vaccine available widespread to the human population where infection is centered
c. Trapping and poisoning rodents near urban and suburban communities
d. Dusting rodent burrows with insecticide to kill fleas

45. John recently visited Lava Hot Spring and spent some time soaking in the hot tubs. Afterwards he noticed his back had broken out in an itchy rash. What gram-negative species had he been infected by?

46. Which of the following is E. coli O157:H7 NOT likely to be found in?
a. raw hamburger
b. unpasteurized fruit juices
c. lettuce
d. custards
e. dry-cured salami

47. This species most commonly infects cattle, and when it's transmitted to humans, it's usually in people who work in slaughterhouses or veterinary clinics or who handle livestock. What is it?

48. Jimmy is two years old and has developed a hacking cough that produces a "whooping" sound when he inhales. What species has he been infected with?

49. A unique characteristic of many isolates of Pseudomonas useful in identification is:
a. fecal odor
b. fluorescent green pigment
c. drug resistance
d. motility

50. Human brucellosis is also known as
a. Bang disease
b. undulant fever
c. rabbit fever
d. Malta fever

51. Francisella tularensis has which portal of entry?
a. tick bite
b. intestinal
c. respiratory
d. all of the above

52. A classic symptom of pertussis is
a. labored breathing
b. paroxysmal coughing
c. convulsions
d. headache

53. The severe symptoms of pertussis are due to what effect?
a. irritation of the glottis by the microbes
b. pneumonia
c. the destruction of the respiratory epithelium
d. blocked airways
e. both c and d are involved

54. Eschericia coli displays which antigens?
a. capsular
b. somatic
c. flagellar
d. all of the above

55. Which of the following is not an opportunistic enteric bacterium?
a. E. coli
b. Klebsiella
c. Proteus
d. Shigella

56. Which of the following represents a major difference between Salmonella and Shigella infections?
a. mode of infection
b. likelihood of septicemia
c. the portal of entry
d. presence/ absence of fever and diarrhea

57. Complications of typhoid fever are
a. neurological damage
b. intestinal perforation
c. liver abscesses
d. b and c

58. Shigella is transmitted by
a. food
b. flies
c. feces
d. all of the above

59. Haemophilus influenza is ___ and requires special ____ for growth.
a. motile, temperature
b. encapsulated, minerals
c. intracellular, sample swabs
d. fastidious, blood factors

60. Which of the following is not associated with H. influenza infections? a. fever
b. flu
c. stiff neck
d. headache

61. Which of the following are primarily zoonoses?
a. tularemia
b. salmonellosis
c. shigellosis
d. brucellosis
e. pasteurellosis
f. bubonic plague

Key Definitions:

Endotoxin: structural component of Gram-negative outer membranes. Also called Lipid A (part of a lipopolysaccharide)

Enteric:Microorganisms that inhabit the intestines

Iatrogenic: in infection occuring as a result of a medical treatment

Catarral Stage: nasal drainage,congestion, sneezing and some coughing, cause from Bordetlla pertussis ( whooping cough).

Coliform-lactose fermenters

Non-Coliform:non lactose fermenters

Paroxysmal Stage: includes recurrent fits of several abbrupt hacking coughs, followed by a "whoop"

Pseudomonas: an opportunistic pathogen

Septicemia: the presence of pathogenic organisms in the blood-stream, leading to sepsis

Physical and Chemical Control

flattail — Tue, 23 Jun 2009 16:11:19 CDT

Physical and Chemical Agents for Microbial Control
Some questions to ponder:

What is sterilization, and when is it desirous?
When is sterilization not needed?
What products/techniques can be used to achieve sterilization? When would you use one instead of another?
Why are vegetative (actively growing) microbes easier to kill than spores?
Be familiar with the various definitions
How do the various chemical agents work? Know examples within each category. Why would you choose one product over another?
How does non-ionizing radiation differ from ionizing radiation? What applications are there for each?
How about adding a few things to this list yourselves? Perhaps a lot of "how" and "why" questions, such as "how does UV light affect microbes?" or "why is betadine used instead of pure iodine?"

Some definitions:

Sterilization is a method used to destroy all microorganisms and viruses. The most widely used method of sterilization is heat. Chemicals called sterilants can be used, but there are only a few chemicals that can fully destroy microorganisms and viruses. Sterilization is only for inanimate objects because the human body cannot withstand the heat or chemicals used to sterilize. The objects are either sterile or unsterile. They can not be partially sterile.
Germicides are any chemical agent that is able to kill pathogenic microorganisms. These can be used on any living or non-living object but usually will not kill any of the resistant microbial cells. A disinfectant is a physical process or a chemical that is used to kill vegetative pathogens but they do not have any effect on bacterial endo spores. Disinfectants are not used on humans. They are only for inanimate objects because they could be toxic to humans.
Sepsis is the systemic response to an infection that can cause organ failure and maybe even death. It is the growth of microorganisms in the body or having toxins present in the blood or other bodily tissues. Asepsis is the practice to reduce or eliminate contamination from bacteria, viruses, and parasites from getting into a sterile environment to prevent the chance of infections. Commonly used in the health care setting. Sanitation is a cleaning technique that removes microorganisms to a safe level. A type of sanitizer is soap or a detergent. Because something is sanitary does not mean it is completely free of microorganisms, it means that the object is safe to use.
Degermation is a process where you scrub the skin or soak the skin in chemicals.
Disinfection is a process used to destroy vegetative pathogens, but not endospores. Disinfectants are able to kill pathogens on contact. Usually on inanimate objects
Surfactant There are two types of surfactants. They are soap and
Microbial death Microbial death is where there is a permanent loss of reproductive ability. When put in optimum growth conditions the microorganisms will not grow. Knowing if a microorganism is dead is hard because it is impossible to detect any vital signs. Loss of movement is not a good indicator of death either.

Q: Which of the following terms is defined as the destruction of vegetative pathogens but not bacterial endospores?
a. disinfection
b. antisepsis
c. sterilization
A: disinfection

Q: What is the goal of sterilization?
a. the destruction to protozoal trophozoites
b. the destruction of bacterial endospores
c. the destruction or inhibition of vegatative pathogens through chemicals applied to body surfaces
A: the destruction of bacterial endospores

Factors Influencing The Death Rate of Microorganisms
~The permanent loss of reproductive capatability, even under optimum growth conditions~

Length of exposure to a physical or chemical agent
Effect of the microbial load
Resistance of spores
Action of the agent

Factors That Influence Action of Microbial Agents

How many microbes there are
What types of microorganisms they are
The temp and pH of the environment
Dose and intensity of the disinfectant
The way in which the agent is able to kill the microorganism
If there are solvents, inhibitors, or interfering organic matter like blood, saliva, or feces.
Biofilms

Methods of Physical Control

1. Heat 2. Cold Temp 3. Desiccation 4. Radiation 5. Filtration

HEAT

Thermal death point TDP- the lowest temperature required to kill all microbes in a sample in 10 minutes.

Thermal death time TDT- the shortest length of time required to kill all test microbes at a specified temperature.

Moist Heat- use of hot water or steam

steam under pressure non-pressurized

boiling water

pasteurization

Dry Heat- using heat higher than moist heat. Dry heat dehydrates the cell, removing the water necessary for metabolic reactions, and it also denatures proteins. At very high temperatures, dry heat of course oxidizes cells, reducing them to ashes. This is the method used in the laboratory when a loop is flamed or in industry when medical waste is incinerated.

COLD- The principal benefit of cold treatment is to slow growth of cultures and microbes in food during processing and storage.

Microbiostatic- slows the growth of microbes

Used to preserve food, media, and cultures

DESSICATION- To dry at normal environmental temperatures.

lyophilization- to dissolve; freeze drying

Gradual removal of water from cells, leads to metabolic inhibition

Not effective microbial control-many cells retain ability to grow when water is reintroduced.

RADIATION- energy emitted from atomic activities and dispersed at high velocity through matter or space.

irradiation- a bombardment with radiation at a cellular level.Link to irradiation fact sheet Dangers of Irradiation Facilities

Ionizing radiation- Gamma rays (very powerful); Radiant energy consisting of short-wave electromagnetic rays or high speed electrons that cause dislodgement of electrons on target molecules and create ions. (one of the most sensitive targets for ionizing radiation is DNA) Used to sterilize medical supplies and food products. Non-ionizing radiation- Ultraviolet light (little penetrating power); Method of microbial control, best exemplified by ultraviolet light, that causes the formation of abnormal bonds within the DNA of microbes, increasing the rate of mutation. The primary limitation of non-ionizing radiation is its inability to penetrate beyond the surface of an object. UV light thymine pyrimidines, which interfere with replication.
FILTRATION- Physical removal of microbes through a filter.

used to sterilize heat sensitive liquids and air in hospital isolation units.

How sand filtration works

Chemical Agents in Microbial Control
HALOGENS- A group of related chemicals with antimicrobial applications (fluorine, bromine, chlorine, and iodine)

Chlorine Compounds-chlorine- hypochlorites, chloramines; can be sporicidal
Iodine Compounds-Iodine- gentler than chlorine; idophores (betadine); can be sporicidal
PHENOLICS- Disrupts cells membranes and precipitating proteins; bacterial, fungicidal, virucidal; Not sporicidal.

Lysol

Triclosan

Joseph Lister made phenols historically significant in the world of microbiology.
CHLORHEXIDINE- Hibiclens, Hibitane; A surfactant and protein denaturant with broad microbicidal properties. Not sporicidal.
Peridex- mouthwash for gingivitis
ALCOHOLS- colorless hydrocarbons with one or more--OH functional groups. Act as a surfactant, dissolving membrane lipids and coagulating proteins of vegetative bacterial cells and fungi. Not sporicidal.
You can sniff alcohol pads to prevent vomiting.
HYDROGEN PEROXIDE- a colorless, caustic liquid that decomposes in the presence of light, metals, or catalase into water and oxygen gas. Creates free radicals that damage proteins and DNA. Strong solutions are sporicidal.
DETERGENTS & SOAPS- Quaternary ammonia compounds that act as surfactants that alter membrane permeability of some bacteria and fungi. Not sporicidal
Soaps mechanically remove soil and grease contaminating microbes by attaching to each other.
HEAVY METALS-Solutions of silver and mercury kill vegetative cells in low concentrations by inactivating proteins. Not sporicidal

metals are very toxic to humans if ingested, inhaled, or absorbed through the skin, even in small quantities, for the same reasons that they are toxic to microbial cells
the commonly cause allergic reactions
large quantities of biological fluids and wastes nuetralize their actions
microbes can develop resistance to metals

Oligodynamic action- toxic effect of heavy metals on microbes; exact mechanisms not fully understood but enzyme deactivation involved. Colloid particles are very small
Overuse of silver can cause argyria, a condition that permanently discolors the skin, but many people promote the use of colloidal silver, as seen in these testimonials.

Here is Paul Karason, the blue man. He has been treating his dermatitis with colloidal silver, he would drink it and also rub it on his face. In doing so, he now has a condition known as Argyria, the blue-grayish man.

ALDEHYDES- Glutarahydehyde and formaldehyde kill by alkynlating protein and DNA.
Glutaraldehyde in 2% solution (CIDEX) used as sterilant for heat sensitive instruments.
Formaldehyde is a disinfectant, preservative, and toxicity limits use.
GASES AND AEROSOLS- Ethylene Oxide- steralizes

Resistance of Microbial Forms

Highest resistance

Bacterial endospores

Moderate resistance

Protozoan cysts; some fungal sexual spores (zygospores); some viruses. In general naked viruses are more resistant then enveloped forms.

Least resistance

Most bacterial vegetative cells; (other then zygospores) fungal spores and hyphae; enveloped viruses; yeasts; and protozoan trophozoites.

Mode of Action for Dry Heat
Dry heat dehydrates the cell, removing the water necessary for metabolic reactions, and it also denatures proteins. At very high temperatures, dry heat of course oxidizes cells, reducing them to ashes. This is the method used in the laboratory when a loop is flamed or in industry when medical waste is incinerated.

Q: Microbial death is defined as which of the following?
a. the permenant termination of an organisms vital processes.
b. the permenant loss of reproductive capability, even under optimal growth conditions.
c. the loss of movement in motile microbe.
A: the permenant loss of reporductive capability, even under optimal growth conditions.

QUALITIES OF	CHEMICAL AGENTS	USED IN HEALTH	CARE
Agent	Target Microbes	Level of Activity	Toxicity	Comments
Iodine	Sporicidal (slowly)	Intermediate	Can irritate tissure; toxic if ingested	Iodophors* are milder forms
Phenolics	Some bacteria, viruses, fungi	Low to intermediate	can be absorbed by skin; can cause CNS damage	Poor solubility; expensive
Chlorhexidine *	Most bacteria, some viruses, fungi	Low to intermediate	Low toxicity	Fast-acting, mild, has residual effects
Alcohols	Most bacteria, viruses, fungi	Intermediate	Toxic if ingested; a mild irritant; dries skin

Microbial Genetics

flattail — Tue, 23 Jun 2009 16:09:59 CDT

Some questions to guide your study:

What is the difference between a gene, a chromosome, the genome, a nucleotide, and a base pair?
How do procaryote and eucaryote chromosomes differ? In what ways are they the same?
How can the genetic alphabet, with only four letters, code for tens of thousands of different proteins?
When is DNA replicated, and for what reason? What is the difference between replication and transcription?
- What is different between procaryote and eucaryote replication?
- What is meant by leading strand and lagging strand? What does this have to do with Okazaki fragments?
- How do viruses replicate?
During transcription, what is being copied, and why?
- What is the difference between DNA and mRNA?
- In eucaryotes, what is an exon and what is an intron? What is alternative splicing?
What is the difference between transcription and translation? What structures are involved in translation? What is the role of tRNA?
What is an operon? What is meant by "promoter," "operator," "regulator," and "structural genes?"What about a repressor?
In what ways could an antibiotic target bacterial transcription or translation?
In considering point mutations, how is a missense mutation different than a nonsense mutation?
- Why is a "silent mutation" silent?
- How is a frameshift mutation caused?
In what ways besides mutation can bacteria get new genetic combinations?
- How does conjugation differ from transformation or transduction?

Microbial Genetics
If you are new to genetics, or want a quick review, check out the guided tour of the basics at the U of U Learn Genetics site.

Genetics
Genetics is the scientific study of inherited characteristics given to offspring from parent. It applies to humans and all other living organisms. There are four levels of genetics that are recognized:
Organism level, cell level, chromosome level, and molecular level.

Organism Level: observes the heredity of the whole organism.
Cell Level: examines the heredity of the cell.
Chromosome Level: examines the characteristics and actions of chromosomes.
Molecular Level: deals with the biochemistry of the genes.

Genome: the sum total of genetic material of a cell.
Gene: Fundamental unit of heredity responsible for a given trait.
Chromosome: discrete cellular structure composed of a neatly packaged elongate DNA molecule.

Gene: fundamental unit of heredity responsible for a given trait in an organism.
Nucleotide: the basic unit of DNA structure and main component of DNA. A gene in a bacteria contains several million nucleotides linked end to end. Nucleotides are composed of a phosphate, a deoxyribose sugar, and a nitrogenous base. Nucleotides covalently bond to form a sugar-phosphate linkage that is the backbone of each strand. Each sugar attaches in a repetitive pattern to two phosphates. The nitrogenous bases, purines and pyrimidiens, attach by covalent bonds at the 1' position of the sugar.
Intron: a section of DNA within a gene that doesn't actually code for anything. a sequence of bases in DNA that codes for a protein.
Exon: a sequence of bases in DNA that codes for a protein.
Replicon: the circular bacterial DNA molecule replicates by means of a special configuration.
Transcription: the formation of mRNA using DNA as a template.
Translation: the synthesis of proteins using mRNA as a template.
Transduction: the transfer of genetic material from one microorganism to another by a viral agent (as a bacteriophage).
RNA is encoded like DNA, but its general structure is different in several ways.
Messenger RNA (mRNA): a copy of a structural gene or genes complementary DNA, synthesized by a process similar to the synthesis of the leading strand during DNA replication and the complimentary base-pairing rules ensure that the code will be faithfully copied in the mRNA transcript.
Codons: a series of triplets that read the message transcribed on the mRNA strand.

The DNA Code

The basic unit of DNA structure is the nucleotide. Each of the nucleotides have phosphate, deoxyribose sugar, and a nitrogenous base.
Enzymes Involved in DNA Replication Helicase: Unzipping the DNA helix Primase: Synthesizing as RNA primer DNA polymerase III: Adding bases to the new DNA chain; proofreading the chain for mistakes DNA polymerase I: Removing primer, closing gaps, repairing mismatches Ligase: Final binding of nicks in DNA during synthesis and repair Gyrase: Supercoiling.

Deoxyribose- is a pentose (5-carbon) sugar - formula C5H10O4. It is found in DNA.

Notice the 5 carbon atoms (grey) forming the backbone of the molecule, and the oxygen atom (red) in the ring - which is a 5 sided ring, unlike glucose.
The hydrogen atoms (white) are either attached directly to the carbons, or via oxygen as OH groups - at an angle. The carbon outside the ring has 2 single hydrogen's and an OH group.

Deoxyribose differs from ribose in that it lacks an oxygen at carbon 2 (labelled) - and so has only 2 hydrogen atoms (white).

Q: What term is defined as a certain segment of DNA that contains the necessary code to make a protein or RNA molecule?
a. genome
b. chromosome
c. gene
A: gene

Q: Which statement regarding the structure of the DNA molecule is correct?
a. DNA is anti parallel
b. the nitrogenous bases of the two strands are linked by hydrogen bonds
c. the sequence of base pairs along the DNA molecule is invarient
A: the sequence of base pairs along the DNA molecule is invarient

Enzymes Involved in DNA Replication
Helicase: Unzipping the DNA helix.
Primase: Synthesizing as RNA primer.
DNA polymerase III: Adding bases to the new DNA chain; proofreading the chain for mistakes.
DNA polymerase I: Removing primer, closing gaps, repairing mismatches.
Ligase: Final binding of nicks in DNA during synthesis and repair.
Gyrase: Super-coiling

Q: What enzyme is responisible for coiling the chromosome into a tight bundle by introducing a reversible series of twists into the DNA molecule?
a. DNA Gyrase
b. Helicase
c. Primase
A: DNA Gyrase
Types of Ribonucleic Acid

RNA Type	Contains Codes For	Function in Cell	Translated
Messenger (mRNA)	Sequence of amino acids in protein	Carries the DNA master code to the ribosomes	Yes
Transfer (tRNA)	A cloverleaf tRNA to carry amino acids	Brings amino acids to ribosomes during translation	No
Ribosomal (rRNA)	Several large structural rRNA molecules	Forms the major part of a ribosomes and participates in protein synthesis	No
Micro (miRNA) (siRNA)	Regulatory RNAs	Regulation of gene expression and coiling of chromatin	No
Primer	An RNA that can begin DNA replication	Primes DNA	No
Ribozymes	RNA enzymes, parts of splicer enzymes	Remove introns from other RNAs in eucaryotes	No

MUTATIONS

Mutations are permanent changes in the genome of a microbe. They may be spontaneous or induced.
Point mutations entail a change in one or a few bases and are categorized based on the effect of the change on the nucleotide(s).
1. Missense mutations: a mutation in which a change in the DNA sequence results in a different amino acid being incorporated into a protein, with varying results. ie: Sickle Cell Anemia they can create a faulty, non functional, (or less functional) protein, they produce a protein which functions in a different manner or cause no significant alteraltion in protein function.
2. Nonsense mutations: a mutation that changes an amino acid-producing codon into a stop codon, leading to premature termination of a protein. ie: Cystic Fibrosis.
3. Silent mutations: a mutation that, because of the degeneracy of the genetic code, results in a nucleotide change in both the DNA and mRNA but not the resultant amino acid and thus, not the protein.
4. Back mutations: a mutation that counteracts an earlier mutation, resulting in the restoration of the original DNA.

Mutations are caused two different ways, by the DNA not pairing up correctly, or by mutagens which are things that damage DNA. With point mutagens there is an alteration of one or more of the bases. Frame-shift mutagens is where there is an insertion or deletion of bases that can interrupt the reading pattern.
Spontaneous mutations are a random change in the DNA that come from errors happening during replication. The cause of these changes are unknown. Induced mutations are caused by being exposed to known mutagens. These known mutagens are physical or chemical and interact with DNA in a negative way. Some physical objects that are able to alter DNA are radiation, UV , X-rays, and high energy gamma rays. Some chemical objects that are able to alter DNA are acridine dyes, agricultural chemicals, and industrial chemicals.
Induced mutations result from exposure to known mutagens, which are primarily physical or chemical agents that interact with DNA in a disruptive nammer. The carefully controlled use of mutagens has provided a useful wy ti induce mutant strains of microorganisms for study.

The Ames Test

The Ames test is a test to determine if a chemical is a mutagen or not. It is based on assuming that any chemical that is a mutagen can turn out to be a carcinogen that causes cancer. A lot of chemicals may not be mutagens but can turn into mutagens once the body has had a chance to metabolize them.
The Ames test uses Salmonella bacteria that are exposed to chemicals. After being exposed, the bacteria is observed for any changes in their growth. One problem with this test is that some of the chemicals that actually do cause cancer do not test positively with the Ames test, and some of the chemicals that test positive do actually cause cancer. It is not always accurate.

Positive and Negative Effects of Mutagens

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While some mutations of genes are helpful by causing organisms adapt to changes , others are harmful.

E. coli has single chromosome that have 4,288 genes, imagine only having more in a human cell that is ten times as many into 46 chromosomes.

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1. ________ is the study of the inheritance, or heredity, of living things.
a. DNA Code
b. Replicon
c. Genetics
d. Translation

2. ______ is the sum total of genetic material of a cell.
a. Chromosome
b. Cell Level
c. DNA Code
d. Genome

3. ________ is the basic unit of DNA structure.
a. DNA Code
b. Replicon
c. Nucleotide
d. Genome

4. _________is a mutation that changes an amino acid-producing codon into a stop codon, leading to premature termination of a protein.
a. Back mutations
b. Silent mutations
c. Missense mutations
d. Nonsense mutations

5. Sickle cell anemia is caused by what kind of mutation?
a. Back Mutation
b. Silent Mutation
c. Nonsense Mutation
d. Missense Mutation

6. Rifamyicins, Tetracyclines and Aminoglycosides are classes of antibiotics that are effective because they:
a. interfere with transcription and translation processes in microorganisms
b. catalyze transcription and translation processes in microorganisms
c. interfere with transcription processes in microorganisms
d. catalyze with translation processes in microorganisms

7. The Ames Test measures:
a. the mutagenicity of chemicals by determining the ability of a chemical to induce mutations in bacteria.
b. the genetic material contained in 'naked' DNA fragments from a donor cell to a competent recipient cell
c. the mutagenicity of organic molecules by determining the ability of molecules to induce mutations in bacteria
d. the severity of Sickle Cell Anemia

8. Cystic Fibrosis is cased by what kind of mutation?
a. Missense Mutation
b. Nonsense Mutation
c. Silent Mutation
d. Back Mutation

9. As a general rule, the template strand on DNA will always begin with?
a. TAC
b. AUG
c. ATG
d. UAC

10. The base pairs are held together primarily by?
a. covalent bonds
b. hydrogen bonds
c. ionic bonds
d. gyrases

11. The replication process includes
a. uncoil the parent DNA molecule
b. unzip the hydrogen bonds between the base pairs
c. synthesize two new strands
d. all of these are correct