Reduction of Methicillin-Resistant Staphylococcus aureus Infection among Veterans in Atlanta

OBJECTIVE. Describe local changes in the incidence of community-onset and hospital-onset methicillin-resistant Staphylococcus aureus (MRSA) infection and evaluate the impact of MRSA active surveillance on hospital-onset infection. DESIGN. Observational study using prospectively collected data. SETTING. Atlanta Veterans Affairs Medical Center (AVAMC). PATIENTS. All patients seen at the AVAMC over an 8-year period with clinically and microbiologically proven MRSA infection. METHODS. All clinical cultures positive for MRSA were prospectively identified, and corresponding clinical data were reviewed. MRSA infections were classified into standard clinical and epidemiologic categories. The Veterans Health Administration implemented the MRSA directive in October 2007, which required active surveillance cultures in acute care settings. RESULTS. The incidence of community-onset MRSA infection peaked in 2007 at 5.45 MRSA infections per 1,000 veterans and decreased to 3.14 infections per 1,000 veterans in 2011 (P <= .001 for trend). Clinical and epidemiologic categories of MRSA infections did not change throughout the study period. The prevalence of nasal MRSA colonization among veterans admitted to AVAMC decreased from 15.8% in 2007 to 11.2% in 2011 (P<.001 for trend). The rate of intensive care unit (ICU)-related hospital-onset MRSA infection decreased from October 2005 through March 2007, before the MRSA directive. Rates of ICU-related hospital-onset MRSA infection remained stable after the implementation of active surveillance cultures. No change was observed in rates of non-ICU-related hospital-onset MRSA infection. CONCLUSIONS. Our study of the AVAMC population over an 8-year period shows a consistent trend of reduction in the incidence of MRSA infection in both the community and healthcare settings. The etiology of this reduction is most likely multifactorial. Infect Control Hosp Epidemiol 2013;34(1):62-68