title: Emergence of glutaraldehyde-resistant Pseudomonas aeruginosa.
abstract: OBJECTIVE
  In November 2009, routine sampling of endoscopes performed to monitor the effectiveness of the endoscope-cleaning procedure at our hospital detected Pseudomonas aeruginosa. Herein we report the results of the subsequent investigation.
  
  
  METHODS
  The investigation included environmental cultures for source investigation, molecular analysis by pulsed-field gel electrophoresis (PFGE) to reveal the identity of the strains, and determination of the bactericidal activity of the glutaraldehyde-based disinfectant used for automated endoscope reprocessing. In addition, patient outcome was analyzed by medical chart review, and incidence rates of clinical samples with P. aeruginosa were compared.
  
  
  METHODS
  The University Hospital of Basel is an 855-bed tertiary care center in Basel, Switzerland. Approximately 1,700 flexible bronchoscopic, 2,500 gastroscopic, 1,400 colonoscopic, 140 endoscopic retrograde cholangiopancreatographic, and 140 endosonographic procedures are performed annually.
  
  
  RESULTS
  P. aeruginosa was detected in samples obtained from endoscopes in November 2009 for the first time since the initiation of surveillance in 2006. It was found in the rinsing water and in the drain of 1 of the 2 automated endoscope reprocessors. PFGE revealed 2 distinct P. aeruginosa strains, one in each reprocessor. The glutaraldehyde-based disinfectant showed no activity against the 2 pseudo-outbreak strains when used in the recommended concentration under standard conditions. After medical chart review, 6 patients with lower respiratory tract and bloodstream infections were identified as having a possible epidemiological link to the pseudo-outbreak strain.
  
  
  CONCLUSIONS
  This is the first description of a pseudo-outbreak caused by P. aeruginosa with reduced susceptibility to an aldehyde-based disinfectant routinely used in the automated processing of endoscopes.
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland.
authors.forename: Sarah
authors.initials: S
authors.lastname: Tschudin-Sutter
authors.forename: Reno
authors.initials: R
authors.lastname: Frei
authors.forename: Günter
authors.initials: G
authors.lastname: Kampf
authors.forename: Michael
authors.initials: M
authors.lastname: Tamm
authors.forename: Eric
authors.initials: E
authors.lastname: Pflimlin
authors.forename: Manuel
authors.initials: M
authors.lastname: Battegay
authors.forename: Andreas Franz
authors.initials: AF
authors.lastname: Widmer
mesh_terms: D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology* / Q000517:prevention & control / Q000635:transmission*; D004196:Disease Outbreaks; D004202:Disinfectants / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D019723:Endoscopes / Q000382:microbiology*; D004866:Equipment Contamination; D005976:Glutaral / Q000494:pharmacology; D006785:Hospitals, University; D006801:Humans; D017053:Infection Control / Q000379:methods; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification*; D013557:Switzerland / Q000453:epidemiology
chemical_list: D004202:Disinfectants; D005976:Glutaral