MRSA

I've been saying for a while now that the 'piggy MRSA*', known as ST398, is going to be a problem. Always listen to the Mad Biologist. Last week, I was talking to someone who is monitoring MRSA in the New York area, and they've seen two cases of ST398 MRSA in hospitals. This really shouldn't come as a surprise since ST398 is sweeping through the swine population. The only question now is will ST398 simply replace the predominant MRSA strains, or will it add to the total number of MRSA infections and deaths. Of course, those aren't mutually exclusive possibilities... *MRSA is methicillin…
So while I was at the American Society for Microbiology meeting this week (and my talk went fine, thanks for asking), I saw a poster by one of ScienceBlogling Tara's students, Abby Harper, about MRSA (methicillin resistant Staphylococcus aureus) in pigs. In the past, I've talked about how, in Europe, there is a strain of MRSA that is sweeping through pigs in Europe, ST398. Essentially, this is a silent epidemic sweeping through pigs (it doesn't seem to cause that much disease is pigs; it's primarily a commensal). In agricultural communities, it seems to be spreading from pigs to people.…
Over at Shakespeare's Sister, I came across this link to an announcement of a new Chlorox disinfectant that is "a one-step, labor-saving solution for killing both strains of MRSA." There seems to be some confusion here. Let's start with the basics. MRSA is the bacterium methicillin resistant Staphylococcus aureus. Traditionally, MRSA has been classified into two kinds: CA-MRSA, community-acquired MRSA, and HA-MRSA, hospital-acquired MRSA*. A CA-MRSA infection is defined as an infection that occurs in a patient who has been in the hospital for less than 48 hours; in other words, they…
A recent article by National Institute of Allergy and Infectious Diseases (NIAID) staff emphasized that NIAID funds over $800 million annually to study antimicrobial resistance. I've heard this same argument many times, and, every time, people always grumble about how that money includes all microorganisms, as opposed to bacterial antibiotic resistance (NIAID never breaks the money down by organism). In particular, the ESKAPE organisms (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, and Enterobacter species), most of which…
An outbreak of vancomycin resistant MRSA, or VMRSA, would be the 'perfect microbiological storm', even worse than vancomycin resistant Staphylococcus aureus (VRSA). The only currently available antibiotics that would be effective against it would have to be used off-label, and are not very effective against sepsis (bloodstream) infections. Fortunately, VRSA is observed only anecdotally: a single patient, usually on long-term vancomycin therapy, is infected with it, and it is not spread to other patients or healthy people. One reason is that most patients with VRSA are already in hospitals…
One piece of infection control legislation moving (slowly) through Congress is the Healthy Hospitals Act, H.R. 1174 (it's so slow that it's, erm, an act of 2007). H.R. 1174 would amend "the Social Security Act to require public reporting of health care-associated infections data by hospitals and ambulatory surgical centers and to permit the Secretary of Health and Human Services to establish a pilot program to provide incentives to hospitals and ambulatory surgical centers to eliminate the rate of occurrence of such infections." There are many good provisions in this legislation: Hospitals…
I think I was a little too optimistic about MRSA (methicillin resistant Staphylococcus aureus) in pigs staying in pigs and not spreading to humans. A recent study in the Netherlands found that people exposed to pigs were 1000 times (yes, one thousand) more likely to be MRSA carriers than the general population, and the MRSA strain was usually the 'pig' strain. What does this mean? The authors conclude: After introduction of the new MRSA risk category in a hospital [Mad Biologist: screening those in contact with farm animals], which is located in a region with a relatively high density of…
Yesterday, I posted about how feral pigs might be responsible for the spinach-associated E. coli O157:H7 outbreak. A while back, I described the epidemic spread of a new strain of MRSA throughout pigs in Europe. What was puzzling to me was why this MRSA strain, found at forty to sixty-fold greater frequency than all commensal MRSA in humans hadn't entered the human population. A recent paper in Emerging and Infectious Diseases lays out one possible reason--this strain of MRSA does not grow well on retail meat (which is thought to be a major conduit of strains from the farm to humans): A…
The NY Times has an article about the MRSA (methicillin resistant Staphylococcus aureus) strain that is spreading rapidly among gay men. One factor is that a subset of the gay population is immunocompromised due to HIV, and consequently, is more likely to acquire MRSA skin infections. This strain is very drug resistant, unlike most community-acquired MRSA ('CA-MRSA'). Most CA-MRSA, while resistant to methicillin, is sensitive to clindamycin. However, this strain has acquired a plasmid (a transferable 'mini-chromosome') that confer resistance to commonly-used drugs to treat MRSA: "This…
By way of Amanda, I came across this NY Times op-ed by Michael Pollan that discusses the role of agribusiness' misuse of antibiotics in the rise community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA). I've talked about the MRSA 'pig epidemic' before, and, Intelligent Designer knows I've talked about the misuse of antibiotics in agriculture, such as the attempt to get cefquinome approved for use in agriculture (Sack, met Mr. Stupid and Ms. Hammers). But I'm not sure that Pollan is correct about this. The strain of CA-MRSA found in pigs is nothing like those found in healthy…
The Charge of the Light MRSA Brigade A few months ago, I discussed an article that demonstrated that pigs had ridiculously high frequencies of MRSA. ScienceBlogling Revere discusses another paper about pigs and MRSA. Like the previous study (published by some of the same authors), several of the same conclusions can be drawn: These are astronomical rates of MRSA, relative to anything outside of a clinical setting--and the Netherlands' MRSA frequency is an order of magnitude lower than the U.S. One piece of evidence argues for the hypothesis that the use of antibiotics in agriculture, either…
I have a week off, so I've been going to the gym in the morning later than usual. I'm still recovering from the near-lobotomization of morning radio, so I wasn't prepared for a report on the "superbug" on Fox's The Morning Show with Mike and Juliet--think of it as a cheap knockoff of Regis and Kelly. Since the sound wasn't turned on for the television, I should have just left it alone, but no, I had to check out the video on the interwubs when I came home. First, anyone who says that evolutionary biologists suck at communicating should watch this bozo. It's a classic example of how not to…
Because this week is really hectic, I just want to follow up on this post I wrote about MRSA. One of the hidden stories in the rise in the frequency of antibiotic resistant bacterial strains is that this has also been accompanied by an absolute increase in the number of infections. In other words, it's not the case that you used to have 90 sensitive infections and 10 resistant infections per year in your hospital, and now, you have 50 sensitive and 50 resistant infections (which would be bad enough). Instead, you have the same 90 sensitive infections and 90 resistant infections (for a…
According to the Boston Globe, a new study indicates that deaths from the bacterium Staphylococcus aureus ('staph infections') have exceeded AIDS/HIV deaths in the U.S (italics mine): Deaths tied to these infections may exceed those caused by AIDS, said one public health expert commenting on the new study. The report shows just how far one form of the staph germ has spread beyond its traditional hospital setting. The overall incidence rate was about 32 invasive infections per 100,000 people. That's an "astounding" figure, said an editorial in Wednesday's Journal of the American Medical…
We're getting worse at washing our hands according to the Baltimore Sun. One thing I've said many times before, but it bears repeating: the best way to avoid getting sick is to limit contact with someone else who is sick. While that sounds obvious, one very good way to do that is handwashing. Handwashing breaks the 'transmission network' and essentially isolates the sick person. If you view preventing infectious disease as a question of how can I protect myself from disease, then we've already lost. The best measures (vaccination and handwashing) aren't just about protecting yourself,…
...then please take this survey (it's anonymous). The survey designers are trying to understand more about about the concerns of people affected by MRSA. The survey should take about 25 minutes to complete. You can take the survey here. If you know someone who has had a MRSA infection, please forward this link to him or her. Also, if your blog can handle it, please think about posting the link.
MRSA is coming! Run for your lives! ....this little piggy had MRSA up its nose. A recent study from the Netherlands found that 39% of slaughtered pigs carried MRSA. This is particularly surprising since MRSA rates in hospitals in the Netherlands are remarkably low. Even in the U.S., the commensal MRSA frequency in humans is around 1.5%. What's up with the piggies? Here's the abstract; some additional comments afterwards: Recently methicillin resistant Staphylococcus aureus (MRSA) was isolated from pigs and pig farmers in The Netherlands. In order to assess the dissemination of MRSA in…
Since I haven't discussed antibiotic resistance for a while, I want to put that health problem in context. The CDC estimates that every year, over 60,000 U.S. residents die from a hospital-acquired bacterial infection that is resistant to one or more commonly used antibiotics. Roughly 25,000 per year die from bacterial infections resistant to three or more antibiotics (e.g., MRSA). And that's just the infections you catch in the hospital. For a little perspective, HIV/AIDS kills under 18,000 U.S. residents per year. Antibiotic resistance is a serious, albeit neglected, problem. Onto the…
Here's a disturbing paper: "Can methicillin-resistant Staphylococcus aureus be found in an ambulance fleet?" The answer? Yes. From the abstract: OBJECTIVE: To perform an initial screening study of methicillin-resistant Staphylococcus aureus (MRSA) contamination in an ambulance fleet. METHODS: This was a cross-sectional study of MRSA contamination in an ambulance fleet operating in the western United States in June 2006. Five specific areas within each of 21 ambulances (n = 105) were tested for MRSA contamination using dacron swabs moistened with a 0.85% sterile saline solution. These…
No, KPC isn't a new fast food restaurant. It's short for Klebsiella pneumoniae carbapenemase. The bad news: it's very hard to treat. The good news: it's very rare...for now. Actually, the correct term is KPC-possessing K. pneumoniae*, but we'll just use the slang 'KPC'--it's what all the cool microbiologists use (I'll refer to the carbapenemase gene as the 'KPC gene'). KPC causes pneumonia, urinary tract infections, and sepsis; the mortality rate from these infections is extremely high. The KPC gene confers resistance to all cephalosporins and Ã-lactam antibiotics: basically,…