Colistin Does Not Potentiate Ceftazidime-Avibactam Killing of Carbapenem-Resistant Enterobacteriaceae In Vitro or Suppress Emergence of Ceftazidime-Avibactam Resistance

Antimicrob Agents Chemother. 2018 Jul 27;62(8):e01018-18. doi: 10.1128/AAC.01018-18. Print 2018 Aug.

Abstract

We tested ceftazidime-avibactam and colistin against 24 carbapenem-resistant Enterobacteriaceae (CRE) isolates by time-kill studies. Ceftazidime-avibactam at 0.25×, 1×, and 4× the MIC was bactericidal against 8%, 21%, and 88% of the isolates, respectively. Colistin (2 μg/ml) was bactericidal against 83% (12 h) and 42% (24 h) of the isolates. In combination, synergy and antagonism were identified against 13% and 46% of the isolates, respectively. The combination did not suppress ceftazidime-avibactam resistance. Colistin plus ceftazidime-avibactam did not provide a benefit over ceftazidime-avibactam against most CRE isolates.

Keywords: CRE; Klebsiella; Klebsiella pneumoniae; antagonism; ceftazidime-avibactam; colistin; synergy.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Azabicyclo Compounds / pharmacology*
  • Carbapenem-Resistant Enterobacteriaceae / drug effects*
  • Carbapenem-Resistant Enterobacteriaceae / genetics*
  • Ceftazidime / pharmacology*
  • Colistin / pharmacology*
  • Drug Combinations
  • Drug Resistance, Multiple, Bacterial / genetics
  • Microbial Sensitivity Tests

Substances

  • Anti-Bacterial Agents
  • Azabicyclo Compounds
  • Drug Combinations
  • avibactam, ceftazidime drug combination
  • Ceftazidime
  • Colistin