Staphylococcus aureus Bacteremia at Five U.S. Academic Medical Centers, 2008-2011: Significant Geographic Variation in Community-Onset Infections.
Clin Infect Dis. 2014 May 30;
Authors: David MZ, Daum RS, Bayer AS, Chambers HF, Fowler VG, Miller LG, Ostrowsky B, Baesa A, Boyle-Vavra S, Eells SJ, Garcia-Houchins S, Gialanella P, Macias-Gil R, Rude TH, Ruffin F, Sieth J, Volinski J, Spellberg B
BACKGROUND: The incidence of community-onset (CO) methicillin-resistant Staphylococcus aureus (MRSA) bacteremia rose from the late 1990s through the 2000s. However, healthcare- onset (HO) MRSA rates have recently declined in the U.S. and Europe.
METHODS: Data were abstracted from infection prevention databases between January 1, 2008 and December 31, 2011 at five U.S. academic medical centers to determine the number of single-patient blood cultures positive for MRSA and MSSA per calendar year, stratified into CO- and HO infections.
RESULTS: Across the five centers, 4,171 episodes of bacteremia were identified. Center A (Los Angeles, CA) experienced a significant decline in CO-MRSA bacteremia rates (from a peak in 2009 of 0.42 to 0.18 per 1,000 patient days in 2011 [p=0.005]) while CO-MSSA rates remained stable. Centers B (San Francisco, CA), D (Chicago, IL) and E (Raleigh-Durham, NC) experienced a stable incidence of CO-MRSA and CO-MSSA bacteremia. In contrast, at Center C (New York, NY), the incidence of CO-MRSA increased more than three-fold (0.11 to 0.34 cases per 1,000 patient days [<0.001]). At most of the sites HO-MRSA decreased and HO-MSSA rates were stable. USA300 accounted for 52% (104/202) of genotyped MRSA isolates overall, but this varied by center, ranging from 35% to 80%.
CONCLUSIONS: CO-MRSA rates and the contribution of USA300 MRSA varied dramatically across diverse geographical areas in the U.S. Enhanced infection control efforts are unlikely to account for such variation in CO infection rates. Bio-ecological and clinical explanations for geographical differences in CO-MRSA bacteremia rates merit further study.
PMID: 24879783 [PubMed - as supplied by publisher]