title: A pseudo-outbreak due to Acinetobacter species (GIM-1) contamination of the pneumatic transport system of a Large University Hospital.
abstract: OBJECTIVE
  To establish the source and contamination routes resulting in positive clinical and surveillance microbiological cultures with carbapenem-resistant, GIM-1 metallo-β-lactamase-positive Acinetobacter pitii and Acinetobacter radioresistens from 21 patients in 8 departments.
  
  
  METHODS
  Retrospective, descriptive study.
  
  
  METHODS
  A 1,300-bed tertiary care academic medical facility consisting of 90 buildings linked by a pneumatic transport system (PTS).
  
  
  METHODS
  Microbiological workup of the cluster strains included matrix-assisted laser desorption/ionization time-of-flight species identification, phenotypic carbapenemase tests, polymerase chain reaction-based genotyping of carbapenemase, and pulsed-field gel electrophoresis. Outbreak management procedures were employed according to institutional regulations.
  
  
  RESULTS
  The rarity of GIM-1 Acinetobacter species in the hospital and region, the lack of epidemiological links between patients, and the fact that in some patients the apparent colonization was clearly nonnosocomial prompted the suspicion of a pseudo-outbreak. Numerous environmental cultures were positive for GIM-1-positive Acinetobacter (including archived sample requisition forms, PTS capsules, cultures from line-diverter and dispenser stations, and sterilized transport capsules following PTS delivery). Moreover, it was observed that condensation fluid from subterranean PTS tubing resulted in water entry in PTS capsules, possibly conferring specimen contamination. After extensive system disinfection, environmental surveys of the PTS were negative, and no further positive patient specimens were encountered.
  
  
  CONCLUSIONS
  This is the first report of a PTS-associated pseudo-outbreak. The large number of falsely positive patient-related specimens in conjunction with the potential hazard of airborne and contact spread of multidrug-resistant microorganisms (in this case, GIM-1 carbapenem-resistant Acinetobacter species) underscores the need for implementation of infection control-based monitoring and operating procedures in a hospital PTS.
authors.affiliation: Institute of Medical Microbiology and Hygiene, Saarland University Medical Center, Homburg, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Herrmann
authors.forename: Sven
authors.initials: S
authors.lastname: Jungmann
authors.forename: Alexander
authors.initials: A
authors.lastname: Halfmann
authors.forename: Alik
authors.initials: A
authors.lastname: Dawson
authors.forename: Martin
authors.initials: M
authors.lastname: Kaase
authors.forename: Sören
authors.initials: S
authors.lastname: Gatermann
authors.forename: Lutz
authors.initials: L
authors.lastname: von Müller
authors.forename: Barbara C
authors.initials: BC
authors.lastname: Gärtner
mesh_terms: D000150:Acinetobacter / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D000151:Acinetobacter Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D001426:Bacterial Proteins / Q000378:metabolism*; D015780:Carbapenems / Q000494:pharmacology; D002648:Child; D004196:Disease Outbreaks; D004866:Equipment Contamination; D005858:Germany / Q000453:epidemiology; D006747:Hospital Communication Systems; D006785:Hospitals, University; D006801:Humans; D007231:Infant, Newborn; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D015780:Carbapenems; C000604934:beta-lactamase GIM-1, Acinetobacter pittii; D001618:beta-Lactamases; C000604933:beta-lactamase GIM-1, Acinetobacter radioresistens