The mechanism of quinolone resistance in Pseudomonas aeruginosa / 中华临床感染病杂志

ABSTRACT

Objective To investigate the mechanism of quinolone resistance in Psendomonas aeruginosa.Methods The minimum inhibitory concentrations (MICs)of ciprofloxacin and levofloxacin with and without carbonylcyainde-m-chlorophenylhydrazone(CCCP)were determined by agar dilution method.Polymerase chain reaction(PCR)and DNA sequencing were used to study the mutations in quinolone resistance-determining region of gyrA and parC genes.The strains were genotyped by enterbacterial repetitive intergenie consensus-PCR(ERIC-PCR).Results Sixteen quinolones-resistant Pseudomonas aeruginosa strains were obtained.The MICs of ciprofloxacin and levofloxacin were not reduced significantly by adding CCCP.Thr-83→Ile of gyrA and Ser-87→Leu of parC were found simultaneously in 16 strains of resistant Pseudomonas aeruginosa.Analysis of ERIC-PCR products indicated that 16 quinolone-resistant strains had an identical band pattern which was different from that seen in the sensitive strains.Conclusion Mutations in gyrA and parC may be the main mechanism of quinolone resistance in clinical isolates of Pseudomonas aeruginosa.