title: A long-term low-frequency hospital outbreak of KPC-producing Klebsiella pneumoniae involving Intergenus plasmid diffusion and a persisting environmental reservoir.
abstract: BACKGROUND
  To study the molecular characteristics of a long-term, low frequency outbreak of bla KPC-2 in a low prevalence setting involving the hospital environment.
  
  
  RESULTS
  KPC-producing bacteria were screened by selective chromogenic agar and Real-Time PCR. The presence of antibiotic resistance genes was ascribed by PCRs and subsequent sequencing, and the KPC-producing isolates were phylogenetically typed using PFGE and multi-locus sequence typing. Bla KPC-2-plasmids were identified and analysed by S1-nuclease-PFGE hybridization and PCR based replicon typing. A ∼97 kb IncFII plasmid was seen to carry bla KPC-2 in all of the clinical isolates, in one of the isolates recovered from screened patients (1/136), and in the Klebsiella pneumoniae and Enterobacter asburiae isolates recovered from the environment (sinks) in one intensive care unit. The K. pneumoniae strain ST258 was identified in 6 out of 7 patients. An intergenus spread to E. asburiae and an interspecies spread to two different K. pneumoniae clones (ST27 and ST461) of the bla KPC-2 plasmid was discovered. K. pneumoniae ST258 and genetically related E. asburiae strains were found in isolates of both human and environmental origins.
  
  
  CONCLUSIONS
  We document a clonal transmission of the K. pneumoniae ST258 strain, and an intergenus plasmid diffusion of the IncFII plasmid carrying bla KPC-2 in this outbreak. A major reservoir in the patient population could not be unveiled. However, the identification of a persisting environmental reservoir of strains with molecular determinants linked to human isolates, suggests a possible role of the environment in the maintenance of this long-term outbreak.
authors.affiliation: Department of Clinical Microbiology, Sørlandet Hospital HF, Kristiansand, Norway. staale.tofteland@sshf.no
authors.forename: Ståle
authors.initials: S
authors.lastname: Tofteland
authors.forename: Umaer
authors.initials: U
authors.lastname: Naseer
authors.forename: Jan Helge
authors.initials: JH
authors.lastname: Lislevand
authors.forename: Arnfinn
authors.initials: A
authors.lastname: Sundsfjord
authors.forename: Orjan
authors.initials: O
authors.lastname: Samuelsen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001426:Bacterial Proteins / Q000096:biosynthesis; D003428:Cross Infection / Q000453:epidemiology*; D004196:Disease Outbreaks; D004197:Disease Reservoirs / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology*; D007711:Klebsiella pneumoniae / Q000145:classification* / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010957:Plasmids / Q000235:genetics*; D012307:Risk Factors; D001618:beta-Lactamases / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase
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