title: Increased expression of ampC in Pseudomonas aeruginosa mutants selected with ciprofloxacin.
abstract: Two Pseudomonas aeruginosa mutants exhibiting increased expression of ampC were selected during exposure to ciprofloxacin. These mutants also exhibited significant increases in mexCD-oprJ expression, but further studies failed to show a link between the increased expression of mexCD-oprJ and ampC. Increased ampC expression was not related to mutations within ampR, the ampC-ampR intergenic region, ampD, ampDh2, or ampDh3 or to changes in the levels of expression of these amidase genes. However, ampD complementation restored wild-type levels of ampC expression and ceftazidime susceptibility, suggesting alternative mechanisms of ampC regulation.
authors.affiliation: Center for Research in Anti-Infectives and Biotechnology, Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, NE 68178, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Wolter
authors.forename: Amber J
authors.initials: AJ
authors.lastname: Schmidtke
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Hanson
authors.forename: Philip D
authors.initials: PD
authors.lastname: Lister
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002939:Ciprofloxacin / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D015854:Up-Regulation; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D002939:Ciprofloxacin; C048795:AmpC beta-lactamases; D001618:beta-Lactamases