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

Guo Bao Tian, Jennifer M. Adams-Haduch, Magdalena Taracila, Robert A. Bonomo, Hong Ning Wang, Yohei Doi

Research output: Contribution to journalArticle

35 Citations (Scopus)


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 R340, likely allowing for better binding and turnover.

Original languageEnglish
Pages (from-to)4922-4925
Number of pages4
JournalAntimicrobial agents and chemotherapy
Issue number10
Publication statusPublished - 01-10-2011
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Pharmacology (medical)
  • Infectious Diseases

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