title: [Study on the accumulation of fluoroquinolones in clinical isolates of susceptible and multi-drug-resistant Escherichia coli strains].
abstract: OBJECTIVE
  To investigate the active efflux of fluoroquinolones in clinical isolated strains of Escherichia coli.
  
  
  METHODS
  The accumulation of ciprofloxacin and tosufloxacin for clinical isolates of Escherichia coli and the effect of glucose and Carbonyl cyanide mchlorophenyl hydrazone (CCCP) on the uptake of Escherichia coli were determined by a modified fluorometric assay.
  
  
  RESULTS
  The accumulation of ciprofloxacin in sensitive and multi-drug-resistant (MDR) organisms decreased with energy dependence, and the decrease in MDR isolate was prominent. Incubation with CCCP increased the accumulation of ciprofloxacin up to three-fold in MDR isolate but not in sensitive isolate. In contrast, CCCP appeared to have no influence on the uptake of tosufloxacin in Escherichia coli.
  
  
  CONCLUSIONS
  These results indicate that energy-dependent active efflux is one of the mechanisms of hydrophilic fluoroquinolones resistance, but it does not play any role in hydrophobic fluoroquinolones resistance in Escherichia coli.
authors.affiliation: Department of Pharmacology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
authors.forename: Zhi-ping
authors.initials: ZP
authors.lastname: Fang
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Xiao-kang
authors.initials: XK
authors.lastname: Liu
authors.forename: Xiao-hong
authors.initials: XH
authors.lastname: Song
mesh_terms: D000890:Anti-Infective Agents / Q000378:metabolism* / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones