title: Exogenous sources of pseudomonas aeruginosa in intensive care unit patients: implementation of infection control measures and follow-up with molecular typing.
abstract: BACKGROUND
  In 1998, a study in the intensive care unit (ICU) of our institution suggested possible transmission of Pseudomonas aeruginosa from faucet to patient and from patient to patient. Infection-control measures were implemented to reduce the degree of P. aeruginosa colonization in faucets, to reduce the use of faucet water in certain patient care procedures, and to reduce the rate of transmission from patient to patient.
  
  
  OBJECTIVE
  To evaluate the effect of the control measures instituted in 1999 to prevent P. aeruginosa infection and colonization in ICU patients.
  
  
  METHODS
  Prospective, molecular, epidemiological investigation.
  
  
  METHODS
  A 870-bed, university-affiliated, tertiary care teaching hospital.
  
  
  METHODS
  The investigation was performed in a manner identical to the 1998 investigation. ICU patients with a clinical specimen positive for P. aeruginosa were identified prospectively. Swab specimens from the inner part of the ICU faucets were obtained for the culture on 9 occasions between September 1997 and December 2000. All patients and environmental isolates were typed by pulsed-field gel electrophoresis (PFGE).
  
  
  RESULTS
  Compared with the 1998 study, in 2000 we found that the annual incidence of ICU patients colonized or infected with P. aeruginosa had decreased by half (26.6 patients per 1,000 admissions in 2000 vs 59.0 patients per 1,000 admissions in 1998), although the populations of patients were comparable. This decrease was the result of the decreased incidence of cases in which an isolate had a PFGE pattern identical to that of an isolate from a faucet (7.0 cases per 1,000 admissions in 2000, vs 23.6 per 1,000 admissions in 1998) or from another patient (6.5 cases per 1,000 admissions in 2000 vs 16.5 cases per 1,000 admissions in 1998), whereas the incidence of cases in which the isolate had a unique PFGE pattern remained nearly unchanged (13.1 cases per 1,000 admissions in 2000 vs 15.6 cases per 1,000 admissions in 1998).
  
  
  CONCLUSIONS
  These results suggest that infection control measures were effective in decreasing the rate of P. aeruginosa colonization and infection in ICU patients, confirming that P. aeruginosa strains were of exogenous origin in a substantial proportion of patients during the preintervention period.
authors.affiliation: Hospital Preventive Medicine, University Hospital of Lausanne, Lausanne, Switzerland.
authors.forename: Christiane
authors.initials: C
authors.lastname: Petignat
authors.forename: Patrick
authors.initials: P
authors.lastname: Francioli
authors.forename: Immaculee
authors.initials: I
authors.lastname: Nahimana
authors.forename: Aline
authors.initials: A
authors.lastname: Wenger
authors.forename: Jacques
authors.initials: J
authors.lastname: Bille
authors.forename: Marie-Denise
authors.initials: MD
authors.lastname: Schaller
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Revelly
authors.forename: Giorgio
authors.initials: G
authors.lastname: Zanetti
authors.forename: Dominique S
authors.initials: DS
authors.lastname: Blanc
mesh_terms: D016521:Electrophoresis, Gel, Pulsed-Field; D004866:Equipment Contamination; D006801:Humans; D017053:Infection Control / Q000379:methods*; D007362:Intensive Care Units; D017720:Molecular Epidemiology / Q000379:methods*; D011552:Pseudomonas Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000302:isolation & purification*