Accumulation of plasmid-mediated fluoroquinolone resistance genes, qepA and qnrS1, in Enterobacter aerogenes co-producing RmtB and class A beta-lactamase LAP-1.
A new plasmid-mediated fluoroquinolone efflux pump gene, qepA, is known to be associated with the rmtB gene, which confers high-level resistance to aminoglycosides. We investigated the qepA gene in 573 AmpC-producing Enterobacteriaceae including one Citrobacter freundii known to harbor rmtB. Of them, two clonally unrelated E. aerogenes harbored qepA. Both isolates co-harbored rmtB, qnrS1, qepA, and bla(LAP-1) on an IncFI type plasmid. The qepA was flanked by two copies of IS26 containing ISCR3C, tnpA, tnpR, bla(TEM), and rmtB. The qnrS1 and bla(LAP-1) were located upstream of qepA. All the resistance determinants (qepA, qnrS1, rmtB, and bla(LAP-1)) were co-transferred to E. coli J53 by filter mating from both isolates. Although the prevalence of qepA is currently low, considering the presence of ISCR3C and the possibility of co-selection and co-transferability of plasmids, more active surveillance for these multi-drug resistant bacteria and prudent use of antimicrobials are needed.
Park
Yeon-Joon
YJ
Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea. yjpk@catholic.ac.kr
Yu
Jin Kyung
JK
Kim
Sang-Il
SI
Lee
Kyungwon
K
Arakawa
Yoshichika
Y
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003227:Conjugation, Genetic / Q000187:drug effects; D024881:Drug Resistance, Bacterial / Q000187:drug effects / Q000235:genetics*; D021902:Enterobacter aerogenes / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D024841:Fluoroquinolones / Q000494:pharmacology*; D005798:Genes, Bacterial; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics*; D001618:beta-Lactamases / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D001618:beta-Lactamases