title: Beta-lactamase-mediated beta-lactam resistance in Campylobacter species: prevalence of Cj0299 (bla OXA-61) and evidence for a novel beta-Lactamase in C. jejuni.
abstract: Fifty-two percent of 1,288 poultry isolates of campylobacters were ampicillin resistant, and resistance was more common among Campylobacter coli isolates (67.4%) than among Campylobacter jejuni isolates (47.5%). Production of beta-lactamase was typically associated with resistance to ampicillin, amoxicillin (amoxicilline), penicillin, and ticarcillin. Regardless of beta-lactamase production, all isolates were resistant to piperacillin (MICs >or= 256 microg/ml), and most were resistant to carbenicillin, cloxacillin, and cephalosporins. Of all ampicillin-resistant campylobacters tested, 91% (347/380) carried the bla(OXA-61) gene, and 77% (136/175) of those tested with nitrocefin produced a beta-lactamase, presumably OXA-61. The isoelectric point (pI) of OXA-61 was 8.7, and the molecular mass was 31.0 kDa. Insertional inactivation of bla(OXA-61) in C. jejuni NCTC 11168 and two ampicillin-resistant isolates resulted in increased susceptibility to ampicillin, co-amoxiclav (amoxicillin and clavulanic acid), penicillin, carbenicillin, oxacillin, and piperacillin, but the effects on MICs of cephalosporins and imipenem were negligible. Some C. jejuni isolates that lacked bla(OXA-61) produced a beta-lactamase, CjBla2, with a pI of 9.2 and molecular mass of 32.4 kDa. Mass spectrometry confirmed that the most prevalent beta-lactamase was the product of bla(OXA-61), but CjBla2 was not identified. OXA-61 is prevalent among Campylobacter spp. of veterinary origin and is similar to the beta-lactamase previously reported in human isolates. Production of OXA-61 was associated with resistance to penams but not cephalosporins. Co-amoxiclav remained active against all isolates tested.
authors.affiliation: Division of Immunity and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Griggs
authors.forename: Leanne
authors.initials: L
authors.lastname: Peake
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Johnson
authors.forename: Saba
authors.initials: S
authors.lastname: Ghori
authors.forename: A
authors.initials: A
authors.lastname: Mott
authors.forename: Laura J V
authors.initials: LJ
authors.lastname: Piddock
mesh_terms: D000595:Amino Acid Sequence; D000658:Amoxicillin / Q000494:pharmacology; D000667:Ampicillin / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001483:Base Sequence; D015139:Blotting, Southern; D016123:Campylobacter jejuni / Q000187:drug effects* / Q000201:enzymology*; D002228:Carbenicillin / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D002645:Chickens; D003023:Cloxacillin / Q000494:pharmacology; D007525:Isoelectric Focusing; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010406:Penicillins / Q000494:pharmacology; D010878:Piperacillin / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D013982:Ticarcillin / Q000494:pharmacology; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D010406:Penicillins; D000667:Ampicillin; D000658:Amoxicillin; D001618:beta-Lactamases; D013982:Ticarcillin; D002228:Carbenicillin; D003023:Cloxacillin; D010878:Piperacillin