Contrasting methicillin-resistant Staphylococcus aureus colonization in veterans affairs and community nursing homes

PURPOSE: To compare the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) nares colonization, the patterns of MRSA acquisition, and the risk for subsequent MRSA infection between a hospital-based, Department of Veterans Affairs (VA) nursing home care unit (NHCU) and community-based nursing homes. PATIENTS AND METHODS: In this prospective study, 148 residents of three community nursing homes and 55 residents of a VA NHCU had their anterior nares swabbed; repeat cultures were obtained from hospitalized patients and/or individuals colonized with MRSA. Subjects were followed up prospectively for 1 year to note hospitalizations and the development of MRSA infections. RESULTS: The prevalence of MRSA colonization was significantly higher in the VA NHCU than in the community nursing homes (mean +/- SD 30.3% +/- 11% versus 9.9% +/- 4%). The rate of MRSA nares colonization was similar in the two settings. Acquisition of MRSA took place in both the long-term care facilities and hospitals, with 23.8% of incident cases occurring during a hospitalization. Only 3 of the 27 individuals colonized at baseline developed an MRSA infection. A trend toward an increased rate of infection was seen in colonized individuals residing in the community nursing homes versus those in the VA NHCU (relative risk 4.67; 95% CI 0.55 to 39.9). Forty-seven percent of the 55 subjects hospitalized were colonized at some point during the study. In contrast to residents of the VA NHCU, MRSA colonization in the community facilities was a marker for high mortality. CONCLUSIONS: Outcomes from colonization may be different in the VA NHCU population and the community nursing home population.