title: USA300 methicillin-resistant S. aureus (USA300 MRSA) colonization and the risk of MRSA infection in residents of extended-care facilities.
abstract: To examine the pathogenesis of USA300 MRSA infection in long-term care residents, we performed a retrospective cohort study of 1691 adult residents of two extended-care facilities from 2003 to 2007 to assess whether the risk of subsequent MRSA infection is higher in USA300 MRSA-colonized residents compared to non-colonized residents or non-USA300 MRSA colonized residents. Six per cent of residents were colonized with USA300 MRSA; 12% of residents were colonized with non-USA300 MRSA; and 101 residents developed MRSA infection. The risk of infection was twofold higher in residents colonized with USA300 MRSA compared to residents not colonized with MRSA [adjusted hazard ratio 2·3, 95% confidence interval (CI) 1·1-4·5]. The risk of infection in USA300 MRSA-colonized residents was similar to USA300 MRSA non-colonized residents (relative risk 1·1, 95% CI 0·5-2·3). Our findings show that colonization with USA300 MRSA increases the risk of MRSA infection suggesting a similar pathogenesis.
authors.affiliation: Departments of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Shurland
authors.forename: O C
authors.initials: OC
authors.lastname: Stine
authors.forename: R A
authors.initials: RA
authors.lastname: Venezia
authors.forename: M
authors.initials: M
authors.lastname: Zhan
authors.forename: J P
authors.initials: JP
authors.lastname: Furuno
authors.forename: R R
authors.initials: RR
authors.lastname: Miller
authors.forename: M-C
authors.initials: MC
authors.lastname: Roghmann
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D015331:Cohort Studies; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D005838:Genotype; D006801:Humans; D007297:Inpatients; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000302:isolation & purification*; D008875:Middle Aged; D058889:Molecular Typing; D015995:Prevalence; D012189:Retrospective Studies; D018570:Risk Assessment; D012866:Skilled Nursing Facilities; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D014481:United States / Q000453:epidemiology