title: Molecular characterization of extended-spectrum-β-lactamase-producing and plasmid-mediated AmpC β-lactamase-producing Escherichia coli isolated from stray dogs in South Korea.
abstract: A total of 47 extended-spectrum-cephalosporin-resistant Escherichia coli strains isolated from stray dogs in 2006 and 2007 in the Republic of Korea were investigated using molecular methods. Extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase phenotypes were identified in 12 and 23 E. coli isolates, respectively. All 12 ESBL-producing isolates carried bla(CTX-M) genes. The most common CTX-M types were CTX-M-14 (n = 5) and CTX-M-24 (n = 3). Isolates producing CTX-M-3, CTX-M-55, CTX-M-27, and CTX-M-65 were also identified. Twenty-one of 23 AmpC β-lactamase-producing isolates were found to carry bla(CMY-2) genes. TEM-1 was associated with CTX-M and CMY-2 β-lactamases in 4 and 15 isolates, respectively. In addition to bla(TEM-1), two isolates carried bla(DHA-1), and one of them cocarried bla(CMY-2). Both CTX-M and CMY-2 genes were located on large (40 to 170 kb) conjugative plasmids that contained the insertion sequence ISEcp1 upstream of the bla genes. Only in the case of CTX-M genes was there an IS903 sequence downstream of the gene. The spread of ESBLs and AmpC β-lactamases occurred via both horizontal gene transfer, accounting for much of the CTX-M gene dissemination, and clonal spread, accounting for CMY-2 gene dissemination. The horizontal dissemination of bla(CTX-M) and bla(CMY-2) genes was mediated by IncF and IncI1-Iγ plasmids, respectively. The clonal spread of bla(CMY-2) was driven mainly by E. coli strains of virulent phylogroup D lineage ST648. To our knowledge, this is the first report of bla(DHA-1) in E. coli strains isolated from companion animals. This study also represents the first report of CMY-2 β-lactamase-producing E. coli isolates from dogs in the Republic of Korea.
authors.affiliation: Bacterial Disease Division, Animal, Plant, and Fisheries Quarantine and Inspection Agency, Anyang, Gyeonggi-do, Republic of Korea.
authors.forename: Migma Dorji
authors.initials: MD
authors.lastname: Tamang
authors.forename: Hyang-Mi
authors.initials: HM
authors.lastname: Nam
authors.forename: Geum-Chan
authors.initials: GC
authors.lastname: Jang
authors.forename: Su-Ran
authors.initials: SR
authors.lastname: Kim
authors.forename: Myung Hwa
authors.initials: MH
authors.lastname: Chae
authors.forename: Suk-Chan
authors.initials: SC
authors.lastname: Jung
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Byun
authors.forename: Yong Ho
authors.initials: YH
authors.lastname: Park
authors.forename: Suk-Kyung
authors.initials: SK
authors.lastname: Lim
mesh_terms: D000818:Animals; D000835:Animals, Wild; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018550:Cephalosporin Resistance / Q000187:drug effects / Q000235:genetics*; D002511:Cephalosporins / Q000494:pharmacology*; D004283:Dog Diseases / Q000382:microbiology*; D004285:Dogs; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D022761:Gene Transfer, Horizontal; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics*; D056910:Republic of Korea; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D001618:beta-Lactamases