title: Colonization of patients, healthcare workers, and the environment with healthcare-associated Staphylococcus epidermidis genotypes in an intensive care unit: a prospective observational cohort study.
abstract: BACKGROUND
  During the last decades, healthcare-associated genotypes of methicillin-resistant Staphylococcus epidermidis (HA-MRSE) have been established as important opportunistic pathogens. However, data on potential reservoirs on HA-MRSE is limited. The aim of the present study was to investigate the dynamics and to which extent HA-MRSE genotypes colonize patients, healthcare workers (HCWs) and the environment in an intensive care unit (ICU).
  
  
  METHODS
  Over 12 months in 2006-2007, swab samples were obtained from patients admitted directly from the community to the ICU and patients transferred from a referral hospital, as well as from HCWs, and the ICU environment. Patients were sampled every third day during hospitalization. Antibiotic susceptibility testing was performed according to EUCAST guidelines. Pulsed-field gel electrophoresis and multilocus sequence typing were used to determine the genetic relatedness of a subset of MRSE isolates.
  
  
  RESULTS
  We identified 620 MRSE isolates from 570 cultures obtained from 37 HCWs, 14 patients, and 14 environmental surfaces in the ICU. HA-MRSE genotypes were identified at admission in only one of the nine patients admitted directly from the community, of which the majority subsequently were colonized by HA-MRSE genotypes within 3 days during hospitalization. Almost all (89%) of HCWs were nasal carriers of HA-MRSE genotypes. Similarly, a significant proportion of patients transferred from the referral hospital and fomites in the ICU were widely colonized with HA-MRSE genotypes.
  
  
  CONCLUSIONS
  Patients transferred from a referral hospital, HCWs, and the hospital environment serve as important reservoirs for HA-MRSE. These observations highlight the need for implementation of effective infection prevention and control measures aiming at reducing HA-MRSE transmission in the healthcare setting.
authors.affiliation: Department of Clinical Microbiology, Unit of Research, Education and Development - Östersund, Umeå University, SE-901 85, Umeå, Sweden. micael.widerstrom@regionjh.se.
authors.forename: Micael
authors.initials: M
authors.lastname: Widerström
authors.affiliation: Department of Clinical Microbiology, Infectious Diseases, Umeå University, Umeå, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Wiström
authors.affiliation: Department of Clinical Microbiology, Umeå University, Umeå, Sweden.
authors.forename: Helén
authors.initials: H
authors.lastname: Edebro
authors.affiliation: Department of Clinical Microbiology, Unit of Research, Education and Development-Östersund, Umeå University, Umeå, Sweden.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Marklund
authors.affiliation: Department of Clinical Microbiology, Unit of Research, Education and Development-Östersund, Umeå University, Umeå, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Backman
authors.affiliation: Department of Anesthesiology and Intensive Care, Unit of Research, Education and Development-Östersund, Umeå University, Umeå, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Lindqvist
authors.affiliation: Department of Clinical Microbiology, Umeå University, Umeå, Sweden.
authors.forename: Tor
authors.initials: T
authors.lastname: Monsen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003428:Cross Infection / Q000635:transmission; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D006282:Health Personnel; D006761:Hospitals; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D016106:Methicillin Resistance / Q000235:genetics; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D009666:Nose / Q000382:microbiology; D010361:Patients; D011446:Prospective Studies; D013203:Staphylococcal Infections / Q000382:microbiology / Q000635:transmission; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity*; D013548:Sweden
keywords: Cross infection/epidemiology; Cross infection/infection & control; Environmental Microbiology; Healthcare-associated infections; Infectious Disease Transmission; Intensive Care Units; Molecular epidemiology; Multilocus sequence typing (MLST); Professional-to-Patient; Pulsed-field gel electrophoresis (PFGE); Staphylococcus epidermidis