title: Serratia marcescens harbouring SME-type class A carbapenemases in Canada and the presence of blaSME on a novel genomic island, SmarGI1-1.
abstract: OBJECTIVE
  An increasing prevalence since 2010 of Serratia marcescens harbouring the Ambler class A carbapenemase SME prompted us to further characterize these isolates.
  
  
  METHODS
  Isolates harbouring bla(SME) were identified by PCR and sequencing. Phenotypic analysis for carbapenemase activity was carried out by a modified Hodge test and a modified Carba NP test. Antimicrobial susceptibilities were determined by Etest and Vitek 2. Typing was by PFGE of macrorestriction digests. Whole-genome sequencing of three isolates was carried out to characterize the genomic region harbouring the bla(SME)-type genes.
  
  
  RESULTS
  All S. marcescens harbouring SME-type enzymes could be detected using a modified Carba NP test. Isolates harbouring bla(SME) were resistant to penicillins and carbapenems, but remained susceptible to third-generation cephalosporins, as well as fluoroquinolones and trimethoprim/sulfamethoxazole. Isolates exhibited diverse genetic backgrounds, though 57% of isolates were found in three clusters. Analysis of whole-genome sequence data from three isolates revealed that the bla(SME) gene occurred in a novel cryptic prophage genomic island, SmarGI1-1.
  
  
  CONCLUSIONS
  There has been an increasing occurrence of S. marcescens harbouring bla(SME) in Canada since 2010. The bla(SME) gene was found on a genomic island, SmarGI1-1, that can be excised and circularized, which probably contributes to its dissemination amongst S. marcescens.
authors.affiliation: National Microbiology Laboratory, Winnipeg, MB, Canada.
authors.forename: L F
authors.initials: LF
authors.lastname: Mataseje
authors.affiliation: National Microbiology Laboratory, Winnipeg, MB, Canada.
authors.forename: D A
authors.initials: DA
authors.lastname: Boyd
authors.affiliation: London Health Sciences Centre, London, ON, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Delport
authors.affiliation: British Columbia Public Health Microbiology and Reference Laboratory, Vancouver, BC, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Hoang
authors.affiliation: British Columbia Public Health Microbiology and Reference Laboratory, Vancouver, BC, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Imperial
authors.affiliation: Laboratoire de santé publique du Québec, Sainte-Anne-de-Bellevue, QC, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Lefebvre
authors.affiliation: Moncton Hospital, Moncton, NB, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Kuhn
authors.affiliation: Cadham Provincial Laboratory, Winnipeg, MB, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Van Caeseele
authors.affiliation: Mount Sinai Hospital, Toronto, ON, Canada.
authors.forename: B M
authors.initials: BM
authors.lastname: Willey
authors.affiliation: National Microbiology Laboratory, Winnipeg, MB, Canada michael.mulvey@phac-aspc.gc.ca.
authors.forename: M R
authors.initials: MR
authors.lastname: Mulvey
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics*; D002170:Canada; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D022761:Gene Transfer, Horizontal; D014644:Genetic Variation; D044404:Genomic Islands; D006801:Humans; D020071:Interspersed Repetitive Sequences; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D008969:Molecular Sequence Data; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D016868:Serratia Infections / Q000382:microbiology*; D012706:Serratia marcescens / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D001618:beta-Lactamases / Q000032:analysis* / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D001618:beta-Lactamases; C063912:carbapenemase
keywords: carbapenem resistance; infection control; mobilization