title: Nursing home characteristics associated with methicillin-resistant Staphylococcus aureus (MRSA) Burden and Transmission.
abstract: BACKGROUND
  MRSA prevalence in nursing homes often exceeds that in hospitals, but reasons for this are not well understood. We sought to measure MRSA burden in a large number of nursing homes and identify facility characteristics associated with high MRSA burden.
  
  
  METHODS
  We performed nasal swabs of residents from 26 nursing homes to measure MRSA importation and point prevalence, and estimate transmission. Using nursing home administrative data, we identified facility characteristics associated with MRSA point prevalence and estimated transmission risk in multivariate models.
  
  
  RESULTS
  We obtained 1,649 admission and 2,111 point prevalence swabs. Mean MRSA point prevalence was 24%, significantly higher than mean MRSA admission prevalence, 16%, (paired t-test, p<0.001), with a mean estimated MRSA transmission risk of 16%.In multivariate models, higher MRSA point prevalence was associated with higher admission prevalence (p=0.005) and higher proportions of residents with indwelling devices (p=0.01). Higher estimated MRSA transmission risk was associated with higher proportions of residents with diabetes (p=0.01) and lower levels of social engagement (p=0.03).
  
  
  CONCLUSIONS
  MRSA importation was a strong predictor of MRSA prevalence, but MRSA burden and transmission were also associated with nursing homes caring for more residents with chronic illnesses or indwelling devices. Frequent social interaction among residents appeared to be protective of MRSA transmission, suggesting that residents healthy enough to engage in group activities do not incur substantial risks of MRSA from social contact. Identifying characteristics of nursing homes at risk for high MRSA burden and transmission may allow facilities to tailor infection control policies and interventions to mitigate MRSA spread.
authors.affiliation: Division of Infectious Diseases and Health Policy Research Institute, University of California-Irvine School of Medicine, Irvine, CA, USA. courtner@uci.edu
authors.forename: Courtney R
authors.initials: CR
authors.lastname: Murphy
authors.forename: Victor
authors.initials: V
authors.lastname: Quan
authors.forename: Diane
authors.initials: D
authors.lastname: Kim
authors.forename: Ellena
authors.initials: E
authors.lastname: Peterson
authors.forename: Matthew
authors.initials: M
authors.lastname: Whealon
authors.forename: Grace
authors.initials: G
authors.lastname: Tan
authors.forename: Kaye
authors.initials: K
authors.lastname: Evans
authors.forename: Hildy
authors.initials: H
authors.lastname: Meyers
authors.forename: Michele
authors.initials: M
authors.lastname: Cheung
authors.forename: Bruce Y
authors.initials: BY
authors.lastname: Lee
authors.forename: Dana B
authors.initials: DB
authors.lastname: Mukamel
authors.forename: Susan S
authors.initials: SS
authors.lastname: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D008875:Middle Aged; D009666:Nose / Q000382:microbiology; D009735:Nursing Homes; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*; D055815:Young Adult