Copious Community-Associated MRSA in Nursing Homes


CONTACT: Jim Sliwa


WASHINGTON, DC – October 24, 2013 – 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 increasingly present 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. Moreover, the large number of residents admitted directly from hospital with no recent contact with the community reduces the likelihood of a community-associated strain being found among nursing home residents. For these reasons, the investigators were surprised at how prevalent MRSA turned out to be, and how many were community-associated. Investigators swabbed 3,806 nursing homes residents and found that 837 of them carried MRSA, of which 222 (27%) were the most common community-associated strain in the US, says Hudson.


Risk factors for MRSA include diabetes, hemodialysis, and wounds of any kind, especially in cases of hospital-associated MRSA. Various studies have found MRSA to be present in 10-30 percent of diabetic wounds. Older age is also an established risk factor for hospital-associated MRSA. 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.


A copy of the study can be found online at  


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The Journal of Clinical Microbiology is a publication of the American Society for Microbiology (ASM).  The ASM is the largest single life science society, composed of over 39,000 scientists and health professionals. Its mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.