Effects of pump inhibitor on accumulation of ciprofloxacin in pseudomonas aeruginosa clinical isolates

Objective To explore whether active efflux system is present in P.aeruginosa in order to identify the resistance mechanism of P.aeruginosa to Fluoroquinolones antibiotics.Methods The influence of carbonyl cyanide-m-chlorophenylhydrazone(CCCP) on MICs of antibiotics to P.aeruginosa clinical isolates were tested by agar dilution according to NCCLS.The accumulation of ciprofloxacin in P.aeruginosa were measured by a fluorescence method and the influence of CCCP was analyzed.Results 4 P.aeruginosa isolates had the efflux pumps for β-lactam antibiotics or fluoroquinolones.CCCP could dramatically increase the accumulation of ciprofloxacin in P.aeruginosa PA16.However,CCCP had little effect on the accumulation of ciprofloxacin in other P.aeruginosa clinical isolates.Conclusion There may have an active efflux system targeting fluoroquinolones in P.aeruginosa.