Prevalence of plasmid-mediated quinolone resistance in Escherichia coli isolates in Wenzhou, Southern China, 2002-2008.
A total of 514 consecutive clinical Escherichia coli isolates, irrespective of resistance background, were collected in the period 2002-2008 in Wenzhou, southern China, to investigate the prevalence of plasmid-mediated quinolone resistance (PMQR). The dominant PMQR gene was aac(6')-Ib-cr, followed by qnr, whereas qepA was absent. A total of 253 (49.2%) of these isolates were aac(6')-Ib-positive. Subsequently, 134 of these isolates were sequenced and 42 (31.3%) found to harbor aac(6')-Ib-cr, 18 to harbor new aac(6')-Ib mutants, and 74 to harbor wild-type aac(6')-Ib. The genes qnrA, qnrB, and qnrS were found in 2 (0.4%), 6 (1.2%), and 14 (2.7%) of 514 isolates, respectively, with 2 isolates co-harboring qnrB and qnrS genes. Sequencing allowed us to identify qnrA1, qnrB4, qnrB6, and qnrS1 in 20 qnr-positive isolates, with qnrS1 being the most prevalent allele. The genes qnrC and qnrD were not found in any isolates. Interestingly, 35% of qnr-positive isolates and 16.7% of aac(6')-Ib-cr-positive isolates were susceptible to ciprofloxacin. PMQR genes are therefore present in both quinolone-resistant and -susceptible isolates and can also be transferred by conjugation experiments, thus suggesting a likely future increase in quinolone resistance.
Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical College, Wenzhou, China.
Tie-Li
TL
Zhou
Xue-Jun
XJ
Chen
Ming-Ming
MM
Zhou
Yu-Jie
YJ
Zhao
Xin-Hua
XH
Luo
Qi-Yu
QY
Bao
D000123:Acetyltransferases / Q000235:genetics; D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002681:China / Q000453:epidemiology; D002939:Ciprofloxacin / Q000494:pharmacology; D003227:Conjugation, Genetic; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D015995:Prevalence; D015363:Quinolones / Q000494:pharmacology*; D017422:Sequence Analysis, DNA
D000890:Anti-Infective Agents; D029968:Escherichia coli Proteins; C485384:Qnr protein, E coli; D015363:Quinolones; D002939:Ciprofloxacin; D000123:Acetyltransferases