title: Interindividual Contacts and Carriage of Methicillin-Resistant Staphylococcus aureus: A Nested Case-Control Study.
abstract: BACKGROUND
  Reducing the spread of multidrug-resistant bacteria in hospitals remains a challenge. Current methods are screening of patients, isolation, and adherence to hygiene measures among healthcare workers (HCWs). More specific measures could rely on a better characterization of the contacts at risk of dissemination.
  
  
  OBJECTIVE
  To quantify how close-proximity interactions (CPIs) affected Staphylococcus aureus dissemination. DESIGN Nested case-control study.
  
  
  METHODS
  French long-term care facility in 2009.
  
  
  METHODS
  Patients (n=329) and HCWs (n=261).
  
  
  METHODS
  We recorded CPIs using electronic devices together with S. aureus nasal carriage during 4 months in all participants. Cases consisted of patients showing incident S. aureus colonization and were paired to 8 control patients who did not exhibit incident colonization at the same date. Conditional logistic regression was used to quantify associations between incidence and exposure to demographic, network, and carriage covariables.
  
  
  RESULTS
  The local structure of contacts informed on methicillin-resistant S. aureus (MRSA) carriage acquisition: CPIs with more HCWs were associated with incident MRSA colonization in patients (odds ratio [OR], 1.10 [95% CI, 1.04-1.17] for 1 more HCW), as well as longer CPI durations (1.03 [1.01-1.06] for a 1-hour increase). Joint analysis of carriage and contacts showed increased carriage acquisition in case of CPI with another colonized individual (OR, 1.55 [1.14-2.11] for 1 more HCW). Global network measurements did not capture associations between contacts and carriage.
  
  
  CONCLUSIONS
  Electronically recorded CPIs inform on the risk of MRSA carriage, warranting more study of in-hospital contact networks to design targeted intervention strategies.
authors.affiliation: 1Sorbonne Universités,UPMC Univ Paris 06,UMR_S 1136,Institut Pierre Louis d'Epidémiologie et de Santé Publique,F-75013,Paris,France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Obadia
authors.affiliation: 3INSERM,UMR 1181 "Biostatistics, Biomathematics, Pharmacoepidemiology and Infectious Diseases" (B2PHI),F-75015 Paris,France.
authors.forename: Lulla
authors.initials: L
authors.lastname: Opatowski
authors.affiliation: 6Laboratoire MESuRS,Conservatoire National des Arts et Métiers,75003,Paris,France.
authors.forename: Laura
authors.initials: L
authors.lastname: Temime
authors.affiliation: 7INSERM,U1173,UFR Simone Veil,Versailles-Saint-Quentin University,78180 Saint-Quentin en Yvelines,France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Herrmann
authors.affiliation: 9ENS de Lyon,Université de Lyon,Laboratoire de l'Informatique du Parallélisme (UMR CNRS 5668-ENS de Lyon-UCB Lyon 1),IXXI Rhône Alpes Complex Systems Institute,France.
authors.forename: Éric
authors.initials: É
authors.lastname: Fleury
authors.affiliation: 1Sorbonne Universités,UPMC Univ Paris 06,UMR_S 1136,Institut Pierre Louis d'Epidémiologie et de Santé Publique,F-75013,Paris,France.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Boëlle
authors.affiliation: 3INSERM,UMR 1181 "Biostatistics, Biomathematics, Pharmacoepidemiology and Infectious Diseases" (B2PHI),F-75015 Paris,France.
authors.forename: Didier
authors.initials: D
authors.lastname: Guillemot
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*; D016022:Case-Control Studies; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*; D005260:Female; D006801:Humans; D015994:Incidence; D017758:Infectious Disease Transmission, Patient-to-Professional; D017757:Infectious Disease Transmission, Professional-to-Patient; D008137:Longitudinal Studies; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D009666:Nose / Q000382:microbiology; D012047:Rehabilitation Centers; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*; D013997:Time Factors; D059015:Wireless Technology; D055815:Young Adult