title: Mutations inblaKPC-3That Confer Ceftazidime-Avibactam Resistance Encode Novel KPC-3 Variants That Function as Extended-Spectrum β-Lactamases.
abstract: We identified fourblaKPC-3mutations in ceftazidime-avibactam-resistant clinicalKlebsiella pneumoniaeisolates, corresponding to D179Y, T243M, D179Y/T243M, and EL165-166 KPC-3 variants. Using site-directed mutagenesis and transforming vectors intoEscherichia coli, we conclusively demonstrated that mutantblaKPC-3encoded enzymes that functioned as extended-spectrum β-lactamases; mutations directly conferred higher MICs of ceftazidime-avibactam and decreased the MICs of carbapenems and other β-lactams. Impact was strongest for the D179Y mutant, highlighting the importance of the KPC Ω-loop.
authors.affiliation: University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Ghady
authors.identifier: 0000-0003-0634-8211
authors.initials: G
authors.lastname: Haidar
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania, USA cjc76@pitt.edu.|XDR Pathogen Laboratory, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.|VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, USA.
authors.forename: Cornelius J
authors.initials: CJ
authors.lastname: Clancy
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania, USA.|XDR Pathogen Laboratory, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Ryan K
authors.initials: RK
authors.lastname: Shields
authors.affiliation: XDR Pathogen Laboratory, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Binghua
authors.initials: B
authors.lastname: Hao
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Shaoji
authors.initials: S
authors.lastname: Cheng
authors.affiliation: University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.|University of Pittsburgh, Pittsburgh, Pennsylvania, USA.|XDR Pathogen Laboratory, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: M Hong
authors.initials: MH
authors.lastname: Nguyen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D053961:Azabicyclo Compounds / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D000073182:Carbapenem-Resistant Enterobacteriaceae / Q000187:drug effects / Q000235:genetics; D015780:Carbapenems / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology*; D004338:Drug Combinations; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D016297:Mutagenesis, Site-Directed; D065093:beta-Lactamase Inhibitors / Q000494:pharmacology*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D053961:Azabicyclo Compounds; D001426:Bacterial Proteins; D015780:Carbapenems; D004338:Drug Combinations; C000595613:avibactam, ceftazidime drug combination; D065093:beta-Lactamase Inhibitors; D002442:Ceftazidime; D001618:beta-Lactamases; C495220:beta-lactamase KPC-3, Klebsiella pneumoniae
keywords: KPC; ceftazidime-avibactam; drug resistance mechanisms; site-directed mutagenesis