title: Cephalosporin resistance in Klebsiella pneumoniae from Nova Scotia, Canada.
abstract: From 2116 Klebsiella pneumoniae strains isolated between January 2001 and December 2002 in Nova Scotia, Canada, 25 (1.18%) showed a reduced susceptibility to cefoxitin or extended-spectrum cephalosporins. Narrow-spectrum beta-lactamase genes (bla(SHV-11), bla(SHV-1), bla(SHV-26), bla(SHV-32), bla(SHV-36), and bla(SHV-40)) were the most prevalent. Four new variants were identified (bla(LEN-17), bla(OKP-B-13), bla(OKP-B-14), and bla(OKP-A-11)), representing the 1st description of bla(OKP) in the Americas. Among the extended-spectrum beta-lactamase (ESBL) genes, bla(SHV-2), bla(SHV2a), bla(SHV-12), and bla(CTX-M-15) were detected (ESBL prevalence of 0.14%). Nineteen strains were resistant to cefoxitin (MIC, 32 to >256 microg/mL). Nevertheless, an AmpC-like activity was detected in only 1 strain, which expressed CMY-2. The combined effects of narrow-spectrum beta-lactamase production and decreased or nonexpression of OmpK35/36 porins did not account for the cefoxitin resistance observed in some of these strains.
authors.affiliation: Department of Pathology and Laboratory Medicine, Queen Elizabeth II Health Science Centre, Halifax, NS, Canada, B3H 1V8.
authors.forename: Roberto G
authors.initials: RG
authors.lastname: Melano
authors.forename: Ross J
authors.initials: RJ
authors.lastname: Davidson
authors.forename: Heather L
authors.initials: HL
authors.lastname: Musgrave
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Forward
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018550:Cephalosporin Resistance; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000235:genetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009674:Nova Scotia / Q000453:epidemiology; D010802:Phylogeny
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins