title: Molecular epidemiology of vancomycin-resistant enterococcal bacteraemia: results from the Canadian Nosocomial Infection Surveillance Program, 1999-2009.
abstract: OBJECTIVE
  Vancomycin-resistant enterococci (VRE) can be associated with serious bacteraemia. The focus of this study was to characterize the molecular epidemiology of VRE from bacteraemia cases that were isolated from 1999 to 2009 as part of Canadian Nosocomial Infection Surveillance Program (CNISP) surveillance activities.
  
  
  METHODS
  From 1999 to 2009, enterococci were collected from across Canada in accordance with the CNISP VRE surveillance protocol. MICs were determined using broth microdilution. PCR was used to identify vanA, B, C, D, E, G and L genes. Genetic relatedness was examined using multilocus sequence typing (MLST).
  
  
  RESULTS
  A total of 128 cases of bacteraemia were reported to CNISP from 1999 to 2009. In 2007, a significant increase in bacteraemia rates was observed in western and central Canada. Eighty-one of the 128 bacteraemia isolates were received for further characterization and were identified as Enterococcus faecium. The majority of isolates were from western Canada (60.5%), followed by central (37.0%) and eastern (2.5%) Canada. Susceptibilities were as follows: daptomycin, linezolid, tigecycline and chloramphenicol, 100%; quinupristin/dalfopristin, 96.3%; high-level gentamicin, 71.6%; tetracycline, 50.6%; high-level streptomycin, 44.4%; rifampicin, 21.0%; nitrofurantoin, 11.1%; clindamycin, 8.6%; ciprofloxacin, levofloxacin and moxifloxacin, 1.2%; and ampicillin, 0.0%. vanA contributed to vancomycin resistance in 90.1% of isolates and vanB in 9.9%. A total of 17 sequence types (STs) were observed. Beginning in 2006 there was a shift in ST from ST16, ST17, ST154 and ST80 to ST18, ST412, ST203 and ST584.
  
  
  CONCLUSIONS
  The increase in bacteraemia observed since 2007 in western and central Canada appears to coincide with the shift of MLST STs. All VRE isolates remained susceptible to daptomycin, linezolid, chloramphenicol and tigecycline.
authors.affiliation: Public Health Agency of Canada, Winnipeg, MB, Canada.
authors.forename: M
authors.initials: M
authors.lastname: McCracken
authors.forename: A
authors.initials: A
authors.lastname: Wong
authors.forename: R
authors.initials: R
authors.lastname: Mitchell
authors.forename: D
authors.initials: D
authors.lastname: Gravel
authors.forename: J
authors.initials: J
authors.lastname: Conly
authors.forename: J
authors.initials: J
authors.lastname: Embil
authors.forename: L
authors.initials: L
authors.lastname: Johnston
authors.forename: A
authors.initials: A
authors.lastname: Matlow
authors.forename: D
authors.initials: D
authors.lastname: Ormiston
authors.forename: A E
authors.initials: AE
authors.lastname: Simor
authors.forename: S
authors.initials: S
authors.lastname: Smith
authors.forename: T
authors.initials: T
authors.lastname: Du
authors.forename: R
authors.initials: R
authors.lastname: Hizon
authors.forename: M R
authors.initials: MR
authors.lastname: Mulvey
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics; D016984:Enterococcus faecium / Q000145:classification* / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D005798:Genes, Bacterial; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D016133:Polymerase Chain Reaction; D020713:Vancomycin Resistance; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial
keywords: CC17; E. faecium; MLST; vanA; vancomycin-resistant Enterococcus