title: High Prevalence of β-lactamase and Plasmid-Mediated Quinolone Resistance Genes in Extended-Spectrum Cephalosporin-ResistantEscherichia colifrom Dogs in Shaanxi, China.
abstract: Objective:The aim of this study was to investigate the occurrence and molecular characterization of extended-spectrum β-lactamases (ESBL), plasmid-mediated AmpC β-lactamase (pAmpC) and carbapenemases as well as plasmid-mediated quinolone-resistant (PMQR) among extended-spectrum cephalosporin-resistant (ESC-R)Escherichia colifrom dogs in Shaanxi province in China.Methods:A total of 40 ESC-REscherichia coliselected from 165 Extraintestinal pathogenicE. coli(ExPEC) isolated from dogs were screened and characterized for the genes encoding for the ESBLs, pAmpC, carbapenemases and PMQR genes by PCR and sequencing. Phylogenetic groups, virulence gene profiles and multilocus sequence typing (MLST) were used to investigate the genetic background of the ESC-RE. coliisolates.Results:Among 40 ESC-RE. coli, the predominant β-lactamase gene wasblaCTX-Ms(n= 35), and followed byblaTEM-1(n= 31),blaSHV-12(n= 14),blaOXA-48(n= 8),blaTEM-30(n= 4),blaCMY-2(n= 3) andblaDHA-1(n= 2). The most common specificblaCTX-Mgene subtype wasblaCTX-M-15(n= 31), and followed byblaCTX-M-123(n= 14),blaCTX-M-1(n= 10),blaCTX-M-14(n= 10) andblaCTX-M-9(n= 7). PMQR genes were detected in 32 (80%) isolates, and the predominant PMQR gene wasaac(6')-Ib-cr(n= 26), followed byqnrS(n= 12),qnrD(n= 9),qnrB(n= 8),qepA(n= 4), and all PMQR genes were detected in co-existence with β-lactamase genes.traT(n= 34) andfimH(n= 32) were the most prevalent virulence genes, and virulence genesfimH, iutA, fyuA, malX, iha, andsatwere more prevalent in phylogenetic group B2. The 40 ESC-R isolates analyzed were assigned to 22 sequence types (STs), and the clonal lineages ST131 (n= 10) and ST10 (n= 9) were the predominant STs.Conclusion:High prevalence of β-lantamases and PMQR genes were detected among ESC-RE. colifrom companion animals. This is also the first description of the co-existence of six β-lantamase genes and five PMQR genes in oneE. coliisolate. Moreover, 10 ST131 clones harboring CTX-M-15 were detected.
authors.affiliation: Department of Basic Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University Yangling, China.
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Aquaculture, College of Animal Science and Technology, Northwest A&F University Yangling, China.
authors.forename: Haixia
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Basic Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University Yangling, China.
authors.forename: Yinqian
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Basic Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University Yangling, China.
authors.forename: Caiju
authors.initials: C
authors.lastname: Hao
keywords: Eshcerichia coli; PMQR; cephalosporin resistance; dog; β-lactamases