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Extended-spectrum AmpC cephalosporinase in Acinetobacter baumannii: ADC-56 confers resistance to cefepime.

ABSTRACT: ADC-56, a novel extended-spectrum AmpC (ESAC) ?-lactamase, was identified in an Acinetobacter baumannii clinical isolate. ADC-56 possessed an R148Q change compared with its putative progenitor, ADC-30, which enabled it to hydrolyze cefepime. Molecular modeling suggested that R148 interacted with Q267, E272, and I291 through a hydrogen bond network which constrained the H-10 helix. This permitted cefepime to undergo conformational changes in the active site, with the carboxyl interacting with R340, likely allowing for better binding and turnover.

SUBMITTER: Tian GB

PROVIDER: S-EPMC3186995 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature

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Extended-spectrum AmpC cephalosporinase in Acinetobacter baumannii: ADC-56 confers resistance to cefepime.

Tian Guo-Bao GB Adams-Haduch Jennifer M JM Taracila Magdalena M Bonomo Robert A RA Wang Hong-Ning HN Doi Yohei Y

Antimicrobial agents and chemotherapy 20110725 10

ADC-56, a novel extended-spectrum AmpC (ESAC) β-lactamase, was identified in an Acinetobacter baumannii clinical isolate. ADC-56 possessed an R148Q change compared with its putative progenitor, ADC-30, which enabled it to hydrolyze cefepime. Molecular modeling suggested that R148 interacted with Q267, E272, and I291 through a hydrogen bond network which constrained the H-10 helix. This permitted cefepime to undergo conformational changes in the active site, with the carboxyl interacting with R34 ...[more]

PMID: 21788456

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