Mike the Mad Biologist

Two Thoughts About MRSA ST239

Maryn McKenna has a good article about a new strain of methicillin resistant of Staphylococcus aureus, ST239, aka The Brazilian Clone (as far as I know, no bikini wax is involved…). ST239 is troubling since it’s not only resistant to methicillin, but also resistant to other antibiotics, including clindamycin, tetracycline, cotrimoxazole (also known as Bactrim), moxifloxacin, and gentamicin. While cotrimoxazole and tetracycline are old drugs, they have proven to be reasonably effective against many MRSA. So spread of a multidrug resistant MRSA means that we really only have one drug that approved and effective against all types of infections, vancomycin (linezolid is primarily used against skin and tissue infections).

But this leads to a question–and I haven’t been able to find an answer.

Does ST239 mean there are additional infections? In other words, is ST239 replacing other MRSA strains (which, admittedly were probably easier to treat), or does it represent an additional burden of infection? To what extent is this clone spreading because of a general breakdown in infection control (i.e., more cases of MRSA infections)?

OK, that was, like, three questions, but you get the general idea–and I’m not snarking here. Does anyone know the answers?

But what I found really disconcerting is the abstract Maryn links to, especially this bit:

Among MRSA isolates collected from 1/2007-1/2010, 77/1126 (6.8%) were identified as ST239 from 77 patients.

So the talk is presented in October 2010, and the strain first showed up in hospitals in 2007. I’m assuming these data (i.e., the genetic tests) were generated recently, which means we had no idea whatsoever that these strains were circulating widely for two years. Certainly, most of larger MRSA research community, even those involved with this issue, didn’t know. Timeliness is important, since once we’ve exceeded the ‘odd anecdote’ frequency (i.e., one or two bizarre cases), we are no longer preventing the spread of this strain, but, instead, trying to contain it. At that point, the genie can’t be put back into the bottle.

As part of a real healthcare system (not Obama/Romneycare), it would be really nice if there were a national electronic surveillance system of hospital infections. All of this phenotypic (not genetic though) information, such as antibiotic susceptibility typing, is stored in hospital LIMS systems, and could be retrieved. It’s just a matter of doing it.

Or we could just wait three years to find out we have a problem.


  1. #1 Gingerbaker
    October 28, 2010

    “As part of a real healthcare system (not Obama/Romneycare), it would be really nice if there were a national electronic surveillance system of hospital infections….”


  2. #2 Lorax
    October 28, 2010

    You mean one of them there soshalist helthcares like in that country Dutch people come from? You know where there is close to 0 hospital-acquired MRSA infections? I think you forgot that we’re #1 #1 #1 Go USA!!!

  3. #3 mdb
    October 28, 2010

    Well, as someone who works in MA hospital and has developed the exact reports you say don’t exist, which by the way is a report required by the MA DPH to track existence of the resistant bacteria – I have to ask were you right about anything else?

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