title: Characterization, cloning and sequence analysis of the inducible Ochrobactrum anthropi AmpC beta-lactamase.
abstract: Ochrobactrum anthropi is resistant to most cephalosporins and penicillins due, at least in part, to the inducible expression of a single beta-lactamase. The beta-lactamase gene has been cloned and sequenced. It encodes an AmpC-type class 1 serine active-site enzyme that hydrolyses mainly cephalosporins and is resistant to inhibition by clavulanic acid. Expression of the ampC gene is inducible via a typical AmpR regulator, which is encoded upstream of ampC. Inducible expression is retained following cloning of O. anthropi ampR-ampC into Escherichia coli, confirming that the signal for AmpR activation in O. anthropi is the same as that used in the Enterobacteriaceae. This is the first reported example of an AmpC beta-lactamase outside of the gamma-subdivision of the bacterial kingdom. Genomic searches of other non-gamma-subdivision bacteria revealed a homologous ampR-ampC cluster in the plant symbiont, Sinorhizobium meliloti.
authors.affiliation: Bristol Centre for Antimicrobial Research and Evaluation, Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
authors.forename: C S
authors.initials: CS
authors.lastname: Higgins
authors.forename: M B
authors.initials: MB
authors.lastname: Avison
authors.forename: L
authors.initials: L
authors.lastname: Jamieson
authors.forename: A M
authors.initials: AM
authors.lastname: Simm
authors.forename: P M
authors.initials: PM
authors.lastname: Bennett
authors.forename: T R
authors.initials: TR
authors.lastname: Walsh
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D018432:Drug Resistance, Multiple / Q000235:genetics; D004790:Enzyme Induction; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D020621:Ochrobactrum anthropi / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D010403:Penicillin Resistance / Q000235:genetics; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D047090:beta-Lactams; C071526:AmpR protein, Bacteria; C048795:AmpC beta-lactamases; D001618:beta-Lactamases