title: Prevalence of β-lactamase and 16S rRNA methylase genes among clinical Escherichia coli isolates carrying plasmid-mediated quinolone resistance genes from animals.
abstract: Plasmid-mediated quinolone-resistance (PMQR) genes were determined by polymerase chain reactions (PCRs) in 250 Escherichia coli isolates from food-producing animals in Guangdong, China, in 2009-2010. Then, the prevalence of plasmid-mediated β-lactamase and 16S rRNA methylase genes was determined by PCRs among the PMQR-positive isolates. One hundred fifty-seven (62.8%) isolates were found to harbor at least one PMQR gene, and qnrS (84) and oqxAB (97) were the most two prevalent PMQR genes. β-lactamase (ESBL and/or AmpC type) genes were detected in 106 of the 157 PMQR-positive strains. The bla(TEM-1) (78) was the most prevalent β-lactamase gene in the 157 PMQR-positive isolates, followed by bla(CMY-2) (28), bla(CTX-M) (25), bla(SHV-1) (3), and bla(DHA-1) (3). Twenty-nine were detected to produce more than one type of β-lactamase. The rmtB was the most prevalent 16S rRNA methylase gene detected (11.5%, 18/157), and armA was detected in only two (1.27%, 2/157) isolates, with one isolate coharboring rmtB and armA. Sixteen isolates were found to coharbor the three types of resistance genes detected in this study. Only 1 transconjugant JGDA2 harboring oqxAB, aac(6')-Ib-cr, bla(DHA-1), and rmtB was obtained from the 16 isolates harboring the three types of resistance genes, by conjugation experiment. The results of Southern blot hybridization revealed that oqxAB, bla(DHA-1), and rmtB were colocated on the same plasmid of ∼54 kb in the JGDA2. To our knowledge, this is the first description of the coexistence of the oqxAB, rmtB, and bla(DHA-1) resistance genes on the same plasmid in one E. coli strain.
authors.affiliation: National Reference Laboratory of Veterinary Drug Residues, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.
authors.forename: Bao-Tao
authors.initials: BT
authors.lastname: Liu
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Liao
authors.forename: Lei
authors.initials: L
authors.lastname: Yue
authors.forename: Xue-Ying
authors.initials: XY
authors.lastname: Chen
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.forename: Shou-Shen
authors.initials: SS
authors.lastname: Yang
authors.forename: Jian
authors.initials: J
authors.lastname: Sun
authors.forename: Sen
authors.initials: S
authors.lastname: Zhang
authors.forename: Shun-Di
authors.initials: SD
authors.lastname: Liao
authors.forename: Ya-Hong
authors.initials: YH
authors.lastname: Liu
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015139:Blotting, Southern; D002681:China; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary; D010957:Plasmids; D016133:Polymerase Chain Reaction; D015363:Quinolones / Q000494:pharmacology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics; D012359:tRNA Methyltransferases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D015363:Quinolones; D012336:RNA, Ribosomal, 16S; D012359:tRNA Methyltransferases; D001618:beta-Lactamases