Copious community-associated MRSA in nursing homes

More than one quarter of residents of 26 nursing homes in Orange County, California carry community-associated methicillin-resistant Staphylococcus aureus (MRSA), which spread more easily, and may cause more severe infection than MRSA traditionally associated with healthcare facilities, according to a paper published in the November 2013 issue of the Journal of Clinical Microbiology.

"Nursing homes need to be part of MRSA control strategies in healthcare facilities," says Lyndsey Hudson of Imperial College of London, the lead author on the study.

Community-associated MRSA are strains that did not originate in hospitals. Burden and transmission of MRSA in nursing homes are likely driven by the number of residents with chronic illnesses or indwelling devices according to the study, which is the first-ever to assess MRSA diversity in nursing homes at a population level and across a large region.

Hudson hopes these findings will help clinicians design prevention and mitigation strategies.

The investigators had suspected that community-associated MRSA strains were infiltrating nursing homes, as they had previously been shown to be appearing in hospitals. The low turnover of patients in nursing homes as compared to hospitals dictates a much lower frequency of potential introductions of MRSA into those populations. However, the investigators were surprised at how prevalent the strains turned out to be. A total of 837 nursing home residents, of 3,806 whose noses were swabbed by the investigators, carried community-associated MRSA.

Risk factors for MRSA include diabetic foot ulcers, especially in cases of hospital-acquired MRSA, and various studies have found MRSA to be present in 10-30 percent of diabetic wounds. Additionally, older age is an established risk factor for hospital-acquired MRSA, and indwelling catheters and other medical devices are also risk factors.

"These findings support the need for regional approaches to reduce MRSA," says Hudson. These might include having hospitals and nursing homes work together to identify patients with MRSA, and apply prevention strategies to stop the spread of infection.