Prevalence of plasmid-mediated quinolone resistance qnr genes in Central China

Abstract

A total of 179 Gram-negative bacteria strains collected in Wuhan from 2005 to 2006 were screened for
qnrA, qnrB and qnrS genes by polymerase chain reaction (PCR). The qnrA genes were detected in 3.88%
of Escherichia coli and 7.69% of Enterobacter cloacae, whereas the qnrB genes were found in 6.20% of
E. coli and 7.69% of E. cloacae. 2.33% of E. coli and 18.92% of Klebsiella pneumoniae were positive for
the qnr gene in PCR. Minimal inhibitory concentrations (MICs) results of ciprofloxacin confirmed that
qnrS gene could be present in isolates susceptible to quinolones. Furthermore, the results indicated
that qnr genes were identified on transferable plasmids, and quinolone resistance can be transferred by
bacterial conjugation.