Microblogology

There has been another recall of beef that may be contaminated with the O157/H7 strain of E. coli. The recall is for over 500,000 pounds of beef products that were shipped for further processing to sites in Michigan, Ohio, Colorado, Illinois, Texas, Pennsylvania, and New York.

This contamination was detected in ground beef from Kroger Stores, and so far about 35 people have become ill from eating improperly cooked or handled meat. What people have to know is that contamination with the bacteria is not the problem. The problem is people who do not follow sanitary food handling guidelines and do not cook their meat thoroughly. O157/H7 is only capable of causing disease if it is not killed in the cooking process (dead bacteria are NOT infectious!).

This means you MUST cook your hamburgers or other ground beef products to an internal temperature of 160 degrees F (medium to medium well). Hamburger that has been cooked rare or medium rare will have not reached sufficient internal temperatures to destroy the bacteria that are lurking there  (there WILL be E. coli in your beef, however, it will only be recalled if the strain has properties of the O157/H7 type). From a food quality and safety company website interior color does not indicate “doneness” and states that:

One out of every four hamburgers turns brown before it’s been cooked to a safe internal temperature.

And yet, only 3 percent of consumers checked hamburgers with a food thermometer according to a 1998 consumer food safety survey conducted by the Food and Drug Administration and FSIS

Therefore, just because your burgers are not “pink” in the middle does not mean that they have necessarily reached the proper cooking temperatures. The other major problem is that people just like to eat their burgers rare.

Sadly, I was listening to a radio show for “foodies” (people who like to listen to radio shows about food and cooking) where they were discussing grilling the perfect burger. The chef being interviewed said of course his perfect burger was rare to medium rare, and implied that anything done more thoroughly was pedestrian. To give the show it’s credit, at the end of the segment there was a quick blurb about the FDA recommends cooking your burger to 160 degrees F, however the damage was done. The expert had already implied that the best burger was one that was rare to medium rare, and this is how the listening public will cook their burgers do to show their friends that they are truly someone who is a little pretentious knows food. It is the trendy thing to do, not the safe thing.

E. coli O157/H7 can cause serious illness in healthy adults, but it is most dangerous in the elderly and children under the age of 5 and can cause a lethal complication called hemolytic uremic syndrome (HUS):

About 2%-7% of E. coli O157:H7 infections lead to HUS.

With HUS Infection, the red blood cells are destroyed and the kidneys fail.

In the United States, HUS is the principal cause of acute kidney failure in children, and most cases of hemolytic uremic syndrome are caused by E. coli O157:H7.

So, from the USDA , proper handling of ground beef includes all of the following:

Wash hands with warm, soapy water for at least 20 seconds before and after handling raw meat and poultry. Wash cutting boards, dishes and utensils with hot, soapy water. Immediately clean spills.

Keep raw meat, fish and poultry away from other food that will not be cooked. Use separate cutting boards for raw meat, poultry and egg products and cooked foods.

Consumers should only eat ground beef or ground beef patties that have been cooked to a safe internal temperature of 160°F.

Color is NOT a reliable indicator that ground beef or ground beef patties have been cooked to a temperature high enough to kill harmful bacteria such as E. coli O157:H7.

The only way to be sure ground beef is cooked to a high enough temperature to kill harmful bacteria is to use a thermometer to measure the internal temperature.

Refrigerate raw meat and poultry within two hours after purchase or one hour if temperatures exceed 90°F. Refrigerate cooked meat and poultry within two hours after cooking.

their Meat and Poultry Hotline is 1-888-MPHOTLINE

P.S. What is a “beef clod” anyway?

The immune system has generally been broken down into two defensive arms, the sexy one and the plain-jane sister. The sexy one is the acquired immune response with its elite T cells and antibody producing B cells, cool activation pathways, and seemingly infinite number of receptors.

Then we have the boring, unassuming arm: the innate immune system. Not nearly so sexy. In fact, until recently people haven’t paid much attention to it whatsoever. Things are beginning to change. We are beginning to understand the sophistication and potency of interferon and complement activation, as well as the critical roll of the toll-like receptors in the initiation of the acquired response. And yet, in all of this new exploration, we still had the overlooked stepchild, the neutrophil (aka:the PMN- polymorphonuclear cell). This cell is boring. It does nothing but eat and die. No fancy receptors, no clever mechanisms for dynamically reacting to pathogens, no intricate activation pathways.

However, could this ugly duckling of the immune system be a swan after all? In news reports out of Wake Forrest, Dr. Zheng Cui may have found out that the most overlooked of all cells may have powerful anti-cancer properties. Dr. Cui has been studying differences between mice that clear cancerous lesions and those that do not. And in his studies he actually looked at how PMNs were playing a part. They identified a genetically different type of PMN that appears to be more aggressive towards cancer. When transferring these PMNs into mice with cancer, they saw 100% clearance of tumors. In every mouse tested. Every mouse.

The problem? Mice are not humans. Dr. Cui has been approved for human trials. In another report, it was stated that Dr. Cui’s lab

have developed a test to identify these cancer-killing cells in human blood, and their studies have shown that individual genetic make-ups, different seasons, different ages, and emotional stresses greatly affect these cancer-killing cells.

Can we find the same cancer killing cells as those seen in mice? Will they behave the same way in humans? Can we find Cinderella after the ball? If so, could this really be a possible cure for cancer? Who would have thought it of the unassuming little PMN.

A two new studies by the Evanston Northwestern’s MRSA screening program ( reported by the Chicago Tribune) show that MRSA infections in hospitals can be controlled.

Evanston Northwestern first tested all patients coming into the hospital and detected that 8.5% of all individuals coming into the hospital carried MRSA (remember that you can carry MRSA and not be INFECTED by MRSA).

They then isolated MRSA positive patients coming into the intensive care unit:

Those with the bacteria were placed in isolation, and special precautions were taken, including gowns and gloves for providers and rubdowns with disinfectants.

And what they found was no difference in overall infections with MRSA in the hospital.

However, when they then extended MRSA surveillance to ALL patients admitted the hospital acquired infections dropped by 70%.

We can control MRSA, we just have to be more vigilant.

My blog has been offline for over a week now because my server lost my blog. !!!. Temporarily it seems. Hopefully after a lengthy lawsuit, this won’t happen again. (just kidding).

Actually, I am not sure what to call this. There is a report out in USA Today about a new technique using something which is a combination between gene therapy and cloning.The article discusses research which may show a possible mechanism to keep a child from inheriting a disease due to “crippled” mitochondria. Most people don’t know that every mitochondria in a cell contains a chromosome (called mitochondrial DNA, or mtDNA for short). It is primarily important in keeping the mitochondria functioning. If this chromosome is faulty, the mitochondria will not operate correctly. There are several diseases associated with misfunctioning mitochondria and range from a type of muscular dystrophy to diabetes.

The research described in this article starts with an embryo created through in vitro fertilization where the female donor’s egg contains has defective mitochondria. Since only the egg contains mitochondria (the sperm is simply a DNA delivery vehicle), a second egg is used which contain functional mitochondria. This second egg (which has NOT been fertilized) has had its DNA removed or an “anucleated” egg. Then the nucleus from the fertilized egg is transferred to this egg. So far, the scientists have only let this newly created embryo develop to the blastocyt stage of development.

The title of the article implies that this embryo in effect has three parents, the maternal chromosomes, the paternal chromosomes and the mtDNA found in the recipient egg in their mitochondria. I talked with a number of distinguished scientists in my department who feel that this is indeed true, that it is the entirety of the genetic material that creates the individual.

What I question then is what is happening when scientists create such embryos using human DNA with anucleated animal eggs.

The process involves injecting human DNA into an animal egg cell from which the nucleus has been removed.

Researchers hope to use the hybrid embryos, which must be destroyed after 14 days, which would create stem cells. The stem cells could be used to help find new medical treatments for diseases such as Alzheimer’s, Lou Gehrig’s, and Parkinson’s.

Two teams in the UK have just been given the go ahead to create these chimeras in order to investigate these diseases and how these diseases develop in cells created from these embryos. The embryos in these studies would be created from human DNA which will be inserted into eggs taken from cows. The article states that these studies would be heavily regulated and none of the cells derived from these embryos would be used to treat patients. I am not sure what I think about all this but believe that the ethical issues regarding the development of these embryos should be more throughly discussed. What do you think?

A recent news article detailed two MRSA infections that occurred in one county in California. In one case, a 12 year old boy developed a MRSA infection and subsequently died from the infection. in the second case, a wrestling coach developed a boil that was later diagnosed as being caused by MRSA. The 12 year old boy was described as being involved in an after school wrestling program.

What is bothering is not the fact that the two individuals who contracted the infection are involved in wrestling. It is fairly well established that wrestlers are at risk for developing all kinds of skin infections, and now some of those skin infections are potentially MRSA skin infections. The problem comes in the terminology in the report about how the schools and the people involved in the outbreak tried to “contain” the outbreak.

Some of the measures taken in the case of the 13 year old were to sanitize all mats before and after wrestling meets. But this is a normal standard practice for all wrestling programs. However, for the wrestling coach:

the areas where the coach was thought to have been were cordoned off and sterilized.

the wrestling and weight rooms were closed for three days and disinfected after the coach became ill

What I want to stress (what I have talked about in other blogs) is that S. aureus is a commonly found bacteria. These bacteria live and exist routinely in the nares (noses) of at least 25% of the human population. They colonize our noses without us even being aware they are there.

However, this is a transient state. Individuals who are currently carriers of S. aureus in their noses will at some point stop being carriers, and those of us who are not presently carriers, may become a carrier at some time in the future. People who have staph bacteria in their noses are normal everyday people. You may have staph in YOUR nose, right now. Really.

We shed these (and other bacteria) into our environment during our daily routines. In every day life, people sneeze, itch their noses and transfer bacteria onto surfaces. But people involved in athletic activity have a tendency to shed more due to the physical interactions that happen in these sports. Think of what happens with respiratory droplets (and nasal secretions) when someone is tackled in football. Lots of explosive expulsions. In wrestling, wrestlers will shed bacteria not only onto the wrestling mats, but onto the skin of the person they are wrestling with.

Cleaning the mats was a good thing. But the person who is carrying the bacteria in their nose will probably use the area again. And the staph will be back where it was before. Other people with staph in THEIR noses will use the area and their staph will be present. And that means that we are almost always surrounded by potential infectious organisms. But staph infections are really preventable. Which is why the vast majority of us never have staph infections. As I have said before, simple everyday hygiene is our best protection from staph infections.

How to do this? First and most importantly, wash your hands. This removes the bacteria you have transferred there when you rubbed your nose, and keeps you from transferring your bacteria to other people. People who are involved in physical activity should shower after contact sports. This is especially important in contact sports because small abrasions that may have occurred during a game or practice may have become contaminated with bacteria. Soap and water will remove them before they have time to cause infection. Cover scrapes and cuts with bandages and treat with a topical antibiotic.

So, what I am most worried about is that I am seeing news articles where individuals with MRSA infections are being treated as pariahs. Just remember, if someone you know develops a MRSA infection, they may have gotten the bacteria that caused their infection from someone you know; your mother, your daughter, your son, yourself.

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The North Carolina Department of Public Health wants you to know that turtles are NOT GOOD PETS for small children. In a recent report to the CDC, it reported 103 cases of gastroenteritis (whose symptoms can include vomiting, bloody diarrhea, abdominal cramping as well as fever) occurring in young children who have been in contact with turtles in a 36 state outbreak.

Turtles (as well as most reptiles) are carriers of the organism that causes salmonellosis, Salmonella Paratyphi. This bacteria lives naturally in the gut of the turtles and causes the turtles no problems. However, most small turtles are kept in aquariums, where they defecate into their container. This means that the bacterium is then present not only the little island (with the palm tree) the turtle lives in, but in the water the turtle swims in. This water is a good place for the bacteria to live and grow in. Then, dripping turtles are taken out of the aquarium. Anything the turtle or the turtle water touches is then contaminated with Salmonella. The report stated that two girls who came developed symptoms had:

swum in an unchlorinated, in-ground swimming pool belonging to the family of the older girl. Two pet turtles belonging to the family also were permitted to swim in the pool. The turtles, both of which had carapace lengths of less than 4 inches, had been purchased recently from a pet shop in South Carolina. A water sample collected from the turtle habitat yielded Salmonella Paratyphi

Young children are much more susceptible to this infection. The median age for this outbreak is reported to be 7 and a half years old, (however a number of adults having salmonellosis been identified in this outbreak as well). This report stated that turtles involved in the outbreak came from such venues as pet stores, flea markets and online vendors. There is actually a prohibition from 1972 on the sale of small turtles (under 4 inches in length) in the US for because of the possibility for transmitting disease. There is an exception to this prohibition on turtle sales for scientific, educational or exhibition purposes. It is thought that pet stores are getting around the prohibition by exploiting this exception.

Unfortunately, things can get worse. Pet stores and turtle breaders appeared to have tried to treat the turtles with antibiotics to try to eliminate the source of infection in the turtles. What do you suppose has happened?

Attempts to treat turtles, turtle eggs, and turtle breeding ponds with antibiotics to eliminate Salmonella have not been successful and have resulted in a high prevalence of antibiotic resistance.

So… what to do if you have turtles? They are lovely little animals and should be treated with love as with any other pet. Just do NOT let your children play with them. Think of them as an observation tank, or a fish tank. And when adults are cleaning the tank, make sure to dispose of the material as you would cat littler or dog droppings, then wash your hands!!! Handwashing is an incredibly effective way to prevent transmission.

But, if you have small children and do not have turtles, do not buy them! Pretty simple?

What is the avian flu? How worried should we be? How is it different from the “normal flu”? These are examples of questions I have been getting from my students lately. Additionally, a current news item illustrates the level of ignorance (and potential for disaster) that we may be facing from unwitting sources. So, it is time we understood what the avian flu is and how to deal with it.

First we have try to understand what the influenza (Flu) virus is. The influenza virus is a virus that binds and infects cells of the respiratory system, specifically the ciliated epithelial cells that line your lungs. There are specific receptors on the surface of the virus that allow the virus to infect these cells (the receptors identified as H for hemagglutinin and N for neuraminidase). The H and the N proteins allow the virus to be specific for not only the type of cell (respiratory) it can infect but the species of cell it can infect. So there are influenza viruses that normally infect birds and some that normally only infect humans. There are some rare times when these viruses can infect species other than the one they are specific for.

The normal seasonal flu we see each year is caused by a set of influenza viruses (type A and B) that can bind and easily infect humans. The strains seen in the last few years have been identified as A (H1N1 or H3N2) and type B for the specific receptors found on the surface of these viruses. These viruses replicate in the ciliated epithelial cells of the infected person and then are spread to other people by respiratory droplets containing viral particles when the infected person sneezes, coughs or shakes hands (which are contaminated by viruses). These newly created viruses then bind, infect, replicate and are spread to more people. So person to person spread is easy and what is commonly seen with the seasonal flu.

The avian flu is a naturally occurring type of influenza virus that infects wild birds. It is the receptors on the surface of the virus that make the virus most infectious for birds. Most of the time the infection in these birds does not cause disease. However, we began seeing transmission of this virus (identified as the H5N1 strain) from wild birds to poultry flocks beginning in late 2003. Most of the infected poultry got mildly sick, however it is thought that the virus may have mutated into a more pathogenic form of virus that caused entire flocks of chickens to sicken and die within a two day period. This pathogenic form infects organs and tissues of the infected chickens, not just the respiratory tract. Because it has spread to other organs, it can be spread efficiently in the feces from infected birds to other birds, as well as to humans.

So, how do humans become infected? Only humans who have very close contact with seriously ill birds have so far become infected. Primarily these are people who live in close contact with their flocks, or have been cleaning and processing infected chickens. From the World Health Organization:

many households in Asia depend on poultry for income and food, many families sell or slaughter and consume birds when signs of illness appear in a flock, and this practice has proved difficult to change. Exposure is considered most likely during slaughter, defeathering, butchering, and preparation of poultry for cooking.

This virus cannot infect humans well because its H and N proteins do not bind to human cells well. YET. This is the crux of the problem, because the Flu is a virus that mutates a lot. Small mutations are constantly happening in influenza viruses, and the H5N1 virus could simply mutate into a form that can easily be spread from human to human. Its genome has been compared to a virulent strain that killed 40 million people world wide in 1918 and it is believed that only a relatively few mutations are necessary for the current strain of the avian flu to look like its lethal predecessor.

What we also worry about is that a human who has become infected through direct contact with infected birds will enable the virus to mix with human flu viruses and quickly and easily gain the ability to infect humans. It then may be able to be directly transmitted from human to human, not just through close contact with a diseased chicken. If this pathogenic form of the virus learns to easily spread (probably through respiratory droplets from coughing), the global pandemic of this virus that we have been fearing may just be upon us. This is especially a problem in which the nature of the infection is not well understood.

This is the problem that is currently occurring in India. From the news article above, there is a large outbreak of the lethal H5N1 virus in the West Bengal’s Birbhum district. However, instead of confining the tainted and diseased birds the villagers

feasted on chicken curry to make the best of a huge loss.

And the infection seems to be spreading, West Bengal animal resources minister Anisur Rahaman stated :

“The ignorance of villagers is one of the main hurdles. They are carrying the dead chickens without any protective gear,” he said. “Most villagers are not aware of the disease. They are eating the dead chickens. Their children are playing with the infected chickens in the courtyards. It’s horrible,”

experts have said some outbreaks may not have been reported, as farmers preferred to cover them up, fearing they might not be able to sell their birds in the market.

The Indian outbreak has been suspected to have spread to neighboring Nepal, and Bangladesh. While human death is rare, two more deaths were reported today in Vietnam and Indonesia. The Vietnamese man:

had slaughtered and cooked chickens and geese on his backyard farm,

However, the Indonesian man was in the automotive industry. Officials are trying to find out his route of infection. This brings the total number of humans who have died from avian flu to 221 (with 353 total infections).

Kroger is issuing a recall on their tri-bean salad that may have been contaminated by the organism that causes botulism poisoning, Clostridium botulinum. To understand how this organism causes disease please go to a previous blog where I discuss botulism poisoning in detail. Again, it is not the bacteria that is the problem but the very lethal toxin that they secrete.

The tri-bean salad was sold in the following states: Ohio, Kentucky, Indiana, Colorado, Illinois, Kansas, Michigan, Missouri, Nebraska, New Mexico, Utah, Washington, West Virginia, and Wyoming.

Questions that students have asked me (I get most of this information from textbooks or the CDC:

Q:If the spore is found on food, why don’t we come down with the disease when we eat food out of our garden?

A: Remember the bacteria are anaerobic. They will not grow on the garden vegetables, but the bacterial spores may contaminate the vegetables. The bacteria (and the spores) are not capable of competing in our guts, our normal flora muscles them out. It is only when the veggies are canned that the bacteria can grow in a non-competitive environment and then produce toxin.

Q: Why do we have to worry about toxin in canned food?

A: Once the spores have a place to grow anaerobically, they will become bacteria that can secrete toxin into their environment (i.e. your canned green beans). The toxin is deadly because it can survive the acid environment of the gut to target our nervous system and cause disease as well as death. A very very small amount of toxin can be lethal.

Q:What are symptoms of botulism poisoning?

A: Symptoms usually begin 12-36 hours after ingesting the toxin. Symptoms usually begin with dizzyness, slurred speach, dry mouth and double vision. Most cases have some vomiting, diarrhea or constipation involved. Death is due to respiratory failure from the inactivation of the nerves that allow us to breath.

Lately, much of the news we have been hearing is that we are losing the war against microbes. MRSA is on the uprise, avian flu is around the corner, things are looking grim. But today in the Journal of Experimental Medicine there is a new report that we may have discovered a chink in the armor of one of our more lethal bacterial adversaries, Streptococcus pneumoniae.

Streptococcus pneumoniae is the cause of not only deadly pneumonia (hence, the name..) but can also be a major cause of meningitis, septicemia, as well not so lethal ear infections. It is most deadly against very young children and the elderly. It has been well documented that this bacteria is becoming more and more resistant not only to penicillin but to other antibiotics we use to treat severe infections. Aside from antibiotics, the only other weapon we have had against this deadly pathogen is a vaccine that is used to PREVENT getting the infection in the first place.

Unfortunately, the current vaccine has limitations. It was created to give coverage to 23 of the most common disease causing strains of the bacteria (there have been over 90 different strains of the bacteria identified). Also, the current vaccine is created to the capsule of the bacteria, a part of the bacteria that does not usually give a robust and long lasting immune response. The current vaccine has been conjugated (enhanced) to overcome some of these limitations. However, the real problem comes when you get an infection with one of the strains not covered by the current vaccine. It seems that it has been difficult to configure this vaccine to cover a broader array of disease causing stains.

So the good news is that the scientists involved in the current publication have identified two proteins that appear to be highly conserved among ALL strains of Strep pneumoniae. Using these two proteins as as targets for the immune system to focus on, they were able to generate a protective response against all clinical isolates tested. They are hoping to use this study to create a vaccine that can protect young children and the elderly against all strains of Strep pneumoniae.

Fabulous! Because we don’t have to use antibiotics (that may or may not work) against a foe we have already defeated.