title: Management of a hospital outbreak of extensively drug-resistant Acinetobacter baumannii using a multimodal intervention including daily chlorhexidine baths.
abstract: BACKGROUND
  Extensively drug-resistant Acinetobacter baumannii (XDR-Ab) is an increasingly important cause of healthcare-associated infection. Uncertainties remain concerning optimal control measures for healthcare-associated outbreaks.
  
  
  OBJECTIVE
  To describe the epidemiology and control of an XDR-Ab outbreak that involved multiple units of a large hospital from March 2012 to January 2014.
  
  
  METHODS
  Case-finding included screening of rectum, groin, throat, nose, wounds, iatrogenic portals of entry, and catheterized sites. Antimicrobial susceptibility was evaluated by disc diffusion and E-test. Resistance genes were detected by polymerase chain reaction. Clonality was assessed by pulsed-field gel electrophoresis. Charts of cases were reviewed to identify risk factors for invasive infection. Control measures included isolation and cohorting of cases, hand hygiene reinforcement, environmental decontamination, and source control with daily baths using wipes pre-impregnated with chlorhexidine gluconate.
  
  
  RESULTS
  A single clonal strain of XDR-Ab colonized or infected 29 patients. Five patients died of XDR-Ab bacteraemia. Transmission occurred primarily on two wards. Colonization was detected at all anatomical screening sites; only 57% (16/28) of cases were rectal carriers. Advanced malignancy was a risk factor for bacteraemia (relative risk: 5.8; 95% confidence interval: 1.2-27.0). Transmission ended following implementation of the multimodal control strategy. No additional nosocomial cases occurred during the following 20 months.
  
  
  CONCLUSIONS
  Our study highlights the need to screen multiple anatomic sites to diagnose carriage and identifies risk factors for XDR-Ab bacteraemia. A multimodal intervention that included daily chlorhexidine baths for cases was rapidly followed by the termination of the outbreak. Hospitals should consider similar interventions when managing future XDR-Ab outbreaks.
authors.affiliation: Faculty of Medicine, McGill University, Montreal, Canada.
authors.forename: A P
authors.initials: AP
authors.lastname: Gray
authors.affiliation: Faculty of Medicine, McGill University, Montreal, Canada; Montreal Public Health Department, Montreal, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Allard
authors.affiliation: Montreal Public Health Department, Montreal, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Paré
authors.affiliation: Faculty of Medicine, McGill University, Montreal, Canada; Montreal Public Health Department, Montreal, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Tannenbaum
authors.affiliation: Laboratoire de santé publique du Québec, Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Lefebvre
authors.affiliation: Laboratoire de santé publique du Québec, Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Lévesque
authors.affiliation: National Microbiology Laboratory, Winnipeg, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Mulvey
authors.affiliation: Infection Prevention and Control Unit, Jewish General Hospital-SMBD, Montreal, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Maalouf
authors.affiliation: Infection Prevention and Control Unit, Jewish General Hospital-SMBD, Montreal, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Perna
authors.affiliation: Faculty of Medicine, McGill University, Montreal, Canada; Infection Prevention and Control Unit, Jewish General Hospital-SMBD, Montreal, Canada. Electronic address: yves.longtin@mcgill.ca.
authors.forename: Y
authors.initials: Y
authors.lastname: Longtin
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000302:isolation & purification*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001494:Baths / Q000379:methods*; D002710:Chlorhexidine / Q000008:administration & dosage*; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D004196:Disease Outbreaks; D018562:Disease Transmission, Infectious / Q000517:prevention & control; D004202:Disinfectants / Q000008:administration & dosage*; D052978:Disk Diffusion Antimicrobial Tests; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005798:Genes, Bacterial; D006801:Humans; D017053:Infection Control / Q000379:methods; D008297:Male; D008875:Middle Aged; D058889:Molecular Typing; D016133:Polymerase Chain Reaction
chemical_list: D000900:Anti-Bacterial Agents; D004202:Disinfectants; D002710:Chlorhexidine
keywords: Acinetobacter; Antimicrobial resistance; Chlorhexidine; Healthcare-associated infection; Outbreak; Screening