title: Relationship between nasal colonization and ventilator-associated pneumonia and the role of the environment in transmission of Staphylococcus aureus in intensive care units.
abstract: BACKGROUND
  This study assessed the relationship between nasal colonization and ventilator-associated pneumonia (VAP) by Staphylococcus aureus, as well the role of the environment in the transmission of this organism.
  
  
  METHODS
  We performed a cohort study of patients with VAP caused by methicillin-resistant S aureus (MRSA) or methicillin-sensitive S aureus during 2 years in an adult intensive care unit (ICU). All patients had nasal swab specimens obtained at admission and during the ICU stay. Clinical samples also were collected for analysis, as were samples from the hands of health care professionals and the environment, and were typed using pulsed-field gel electrophoresis.
  
  
  RESULTS
  S aureus VAP represented 12.5% of the cases, and statistical analysis identified colonization as a risk factor for the development of this infection. MRSA was isolated from the environment and hands, indicating the existence of a secondary reservoir. Molecular typing revealed a polyclonal profile; however, clone J was the most frequent (45.5%) among isolates of MRSA tested, with a greater profile of resistance than the other isolates. There was strong evidence suggesting transmission of MRSA to patients from the environment.
  
  
  CONCLUSIONS
  Nasal colonization for S aureus is a risk factor for development of VAP.
authors.affiliation: Institute of Biomedical Science, Federal University of Uberlandia, Minas Gerais, Brazil. Electronic address: lilianrocha23@yahoo.com.br.
authors.forename: Lílian Alves
authors.initials: LA
authors.lastname: Rocha
authors.forename: Rosineide
authors.initials: R
authors.lastname: Marques Ribas
authors.forename: Ana Lúcia
authors.initials: AL
authors.lastname: da Costa Darini
authors.forename: Paulo Pinto
authors.initials: PP
authors.lastname: Gontijo Filho
mesh_terms: D000328:Adult; D015331:Cohort Studies; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D007362:Intensive Care Units; D058889:Molecular Typing; D009296:Nasal Cavity / Q000382:microbiology*; D011023:Pneumonia, Staphylococcal / Q000453:epidemiology* / Q000635:transmission; D053717:Pneumonia, Ventilator-Associated / Q000453:epidemiology*; D011446:Prospective Studies; D012307:Risk Factors; D013211:Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*
keywords: Environment; Nasal colonization; Staphylococcus aureus; Ventilator-associated pneumonia