In this study, we investigated the presence of plasmid-mediated quinolone resistance (PMQR) genes among 101 ciprofloxacin-resistant urinary
Escherichia coli
isolates and searched for mutations in the quinolone-resistance-determining regions (QRDRs) of the DNA gyrase and topoisomerase IV genes in PMQR-carrying isolates. Eight isolates harboured the
qnr and
aac(6’)-Ib-cr genes (3
qnrS1, 1
qnrB19 and 4
aac(6’)-Ib-cr). A mutational analysis of the QRDRs in
qnr and
aac(6’)-Ib-cr-positive isolates revealed mutations in
gyrA,
parC and
parE that might be associated with high levels of resistance to quinolones. No mutation was detected in
gyrB. Rare
gyrA,
parC and
parE mutations were detected outside of the QRDRs. This is the first report of
qnrB19,
qnrS1 and
aac(6’)-Ib-cr-carrying
E. coli isolates in Brazil.
