[Study on the accumulation of fluoroquinolones in clinical isolates of susceptible and multi-drug-resistant Escherichia coli strains].
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.
Fang
Zhi-ping
ZP
Department of Pharmacology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
Xu
Wei
W
Liu
Xiao-kang
XK
Song
Xiao-hong
XH
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
D000890:Anti-Infective Agents; D024841:Fluoroquinolones