MRSA infections declined in HIV+ patients

Dan and I have commented on the nationwide (and worldwide) decline in invasive MRSA infections.  Specifically we've discussed Alex Kallen's JAMA article from August 2010 that reported a continuous decline in invasive MRSA disease in the US from 2005 through 2008, including a 9.4% annual decrease in hospital onset and an estimated 5.7% annual decrease in health care–associated community-onset infections. We also mentioned there has been a 24% decrease in S aureus bacteremia in England and that recent European data demonstrates that more countries are experiencing decreases in the proportion of invasive S aureus infections caused by MRSA than are experiencing increases. However, what is happening with the MRSA epidemiology in high-risk populations, such as those who are HIV positive?

In a research letter just published online in AIDS, Alicia Hidron et al. from the Atlanta VA Medical Center analyzed MRSA infections in HIV+ patients during 2002-2009.  Infections were classified by NHSN criteria and community-onset was determined using the 48-hour rule and CA vs HA-acquired was determined using antibiotic susceptibility phenotype. Over-all, there were 168 patients with 226 MRSA infections (25 bacteremia cases and 180 SSTIs) in the cohort. 94% were community onset and 70% had community-acquired susceptibility profiles. They reported the rates per 1000 patients.  I could explain more, but all you need to see is this figure:

More evidence of an MRSA decline. Caveats: small study, single center, no statistics, no mention of MSSA infections. The authors didn't say when the Atlanta VA started active detection for MRSA, but given that 94% of the infections were community onset, that is largely irrelevant, which is the whole point.  MRSA went up and then MRSA went down and this almost certainly had to do with the complex interaction between the bacteria (likely USA 300) and the patients (immunity).  When you see reports that the VA's MRSA natiowide initiative worked, remember this study.

Hidron et al AIDS 2011