Random MRSA research, ICEID

Came back from the conference and got slammed with work. (Also, snow, three days in succession. What is it about "Spring" that Minnesota does not understand?) So especial thanks to the 15 readers — you know who you are and Google Analytics does too — who have been diligently checking regardless.

I'm going to do a quick wrap on some of the remaining MRSA papers presented at the Emerging Infections conference. (For a wrap-up of flu and foodborne-disease research, see my final conference story at CIDRAP.)

A quick explainer for those who don't make a habit of going to science conferences, you lucky souls you: For many researchers, this is the first presentation of new or incremental findings. Thus, there's no publication to link to — that's why these ICEID posts aren't so content-rich. Many of these papers may end up in a medical journal in the next year, but for now, not even the abstracts are online.

So:

• To generate hypotheses about what leads to CA-MRSA infection, a team from the Minnesota Department of Health and the CDC analyzed the life circumstances of 150 people diagnosed with CA-MRSA or MSSA, and found the strongest correlation was between CA-MRSA and a prior history of boils or prior use of antibiotics. (Lead author: K. Como-Sabetti.)
• In another Minnesota-based report, researchers from the VA Medical Center found that patients who developed MRSA in the hospital had a risk of dying within 6 months that was three times higher than for patients with non-resistant staph. (Lead author: C. Lexau.)
• And, OK, Minnesota trifecta: A team from the MN DoH and the CDC checked the colonization levels of MRSA patients and their household members over a year and found that, even a year after the first diagnosis. one out of every five patients' households had at least one household member who was still colonized — and that use of Bactroban had made no difference. (Lead author: J. Buck.)
• Confirming the hypothesis that MRSA can persist on surfaces and contribute to colonization, Texas researchers swabbed bathroom and common-room surfaces at a university and a jail and found the presence of MRSA was 5 times higher on the jail surfaces (6.1% of samples v. 1.2%). Jails are already known to be hotbeds of CA-MRSA — some of the earliest recognized outbreaks were recorded in jails — and this suggests that in a setting where there is a large amount of MRSA, environmental contamination may keep the bug circulating. (Lead author M. Felkner.)
• An analysis by the Connecticut Department of Public Health of lab-confirmed diagnoses of invasive MRSA between 2001 and 2006 confirms how tricky sorting out HA- and CA-MRSA can be. The incidence of invasive MRSA stayed stable over those five years, but the proportion of community-associated MRSA rose while the proportion of "hospital-onset" (developed no sooner than 48 hours after admission to the hospital) decreased. That makes it sound as though CA-MRSA is increasing overall. But: When the Connecticut state laboratory finegrprinted the strains, they found that 2% of the hospital-onset and 4% of the "hospital-acquired/community-onset" cases were actually caused by community strains, and 76% of the community cases were actually caused by hospital strains. (Lead author: S. Petit.)

That's all on ICEID; tune in two years from now when the conference returns, or stay tuned for more on hospital-acquired infections, mandatory reporting, and disagreements over "search and destroy."