Rising plague, falling plague?

In a continuation of the EIN string I recently blogged about, a commenter discussed the success of an MRSA “search and destroy” program they implemented at their hospital. I thought the response by Brad Spellberg (ID doc extraordinaire, and author of “Rising Plague”) was right on target (and consistent with one of the points Eli and I tried to make in our JAMA editorial):

"With respect to the comment, “With this aggressive search and destroy program, we have had a drop in our MRSA rates for the past 4 years in a row with a marked decline in nosocomial transmissions”, I’d advise caution in interpretation.



I think many healthcare systems are seeing declines in MRSA rates nosocomially, including sites that haven’t done much different. Furthermore, we and others I’ve talked to have been seeing dramatic declines in community MRSA rates as well. Let’s not forget, we have no idea why MRSA emerged into the community, why USA300 took over, and where the related phage 80/81 strain went in 1961 and where it hid for nearly 40 years before re-emerging. Why should we be surprised that it has decided to move on now? Let us not underestimate the impact of changes in bacterial ecology that are not necessarily related to things we’ve done."