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.
- 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.)