title: [Combined drug sensitivity test of 50 strains of extensively drug-resistant Acinetobacter baumannii].
abstract: OBJECTIVE
  To study the in vitro antibacterial activity of meropenem combined with doxycycline, ciprofloxacin, sulbactam or cefoperazone/sulbactam against clinically isolated extensively drug-resistant Acinetobacter baumannii (XDRAB).
  
  
  METHODS
  Using a checker board synergy design, the minimal inhibitory concentration (MIC) of antibiotics against 50 isolates of XDRAB was determined by broth microdilution antifungal susceptibility test. The fractional inhibitory concentration (FIC) index was calculated to determine the combined effect of the antibiotics.
  
  
  RESULTS
  Meropenem showed significantly reduced MIC50 and enhanced antimicrobial activities when combined with doxycycline, sulbactam or cefoperazone/sulbactam. The FIC results suggested that the main actions of doxycycline, sulbactam, and cefoperazone/sulbactam were synergistic (38%, 26%, and 10%, respectively) and addictive (62%, 74%, and 90%, respectively) without indifferent or antagonistic effects. The main actions of meropenem combined with ciprofloxacin were additive (56%) and indifference (44%) with synergistic and antagonistic effects.
  
  
  CONCLUSIONS
  Meropenem combined with doxycycline, sulbactam or cefoperazone/sulbactam shows excellent activity against clinical isolates of XDRAB.
authors.affiliation: Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. E-mail: 314328645@qq.com.
authors.forename: Yidan
authors.initials: Y
authors.lastname: Lu
authors.forename: Yali
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hao
authors.initials: H
authors.lastname: Zhou
authors.forename: Fang
authors.initials: F
authors.lastname: Yu
authors.forename: Shumei
authors.initials: S
authors.lastname: Sun
authors.forename: Yongyu
authors.initials: Y
authors.lastname: Rui
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004338:Drug Combinations; D004357:Drug Synergism; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D013845:Thienamycins / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D013845:Thienamycins; D000077731:Meropenem