title: Plasmid-Mediated Quinolone Resistance in Escherichia coli Isolates from Wild Birds and Chickens in South Korea.
abstract: A total of 2,423 nonduplicate isolates of Escherichia coli recovered from wild birds (n=793) and chickens (n=1,630) in South Korea were investigated for plasmid-mediated quinolone resistance (PMQR) genes. Altogether, 56 isolates with PMQR genes were identified, including 25 (3.2%) from wild birds and 31 (1.9%) from chickens, which were further characterized using molecular methods. Among them, qnrS, aac(6')-Ib-cr, qnrB, and qepA genes were detected in 47 (1.9%), 6 (0.24%), 2 (0.08%), and 1 (0.04%) isolates, respectively. The most prevalent gene, qnrS, was identified in 21 (0.9%) and 26 (1.1%) isolates from wild birds and chickens, respectively. The qnrB gene was identified in two chicken isolates, which included qnrB19 and a novel qnrB44 gene. Plasmid isolation and Southern hybridization revealed that qnrS1 was located on a large (>200 kbp) plasmid. The spread of the PMQR genes was attributed to a combination of horizontal dissemination and clonal expansion. The horizontal dissemination of PMQR genes was mostly mediated by IncK plasmids. Molecular typing demonstrated that the majority of the PMQR-positive isolates were genetically diverse. Only one chicken isolate belonged to ST131, which harbored an additional CMY-2 gene. Our findings suggest that the wild birds could serve as reservoirs of PMQR genes and spread them over long distances through migration. To our knowledge, this is the first report of PMQR genes in Korean wild birds. This study also reports qnrS2, qnrB19, qnrB44, and qepA genes for the first time in animal E. coli isolates from South Korea.
authors.affiliation: 1 Department of Infectious Diseases and Avian Diseases, College of Veterinary Medicine and Korea Zoonosis Research Institute, Chonbuk National University , Iksan, South Korea .
authors.forename: Jae-Young
authors.initials: JY
authors.lastname: Oh
authors.affiliation: 2 Avian Disease Division, Animal and Plant Quarantine Agency , Anyang, South Korea .
authors.forename: Yong-Kuk
authors.initials: YK
authors.lastname: Kwon
authors.affiliation: 3 Bacterial Disease Division, Animal and Plant Quarantine Agency , Anyang, South Korea .
authors.forename: Migma Dorji
authors.initials: MD
authors.lastname: Tamang
authors.affiliation: 1 Department of Infectious Diseases and Avian Diseases, College of Veterinary Medicine and Korea Zoonosis Research Institute, Chonbuk National University , Iksan, South Korea .
authors.forename: Hyung-Kwan
authors.initials: HK
authors.lastname: Jang
authors.affiliation: 2 Avian Disease Division, Animal and Plant Quarantine Agency , Anyang, South Korea .
authors.forename: Ok-Mi
authors.initials: OM
authors.lastname: Jeong
authors.affiliation: 2 Avian Disease Division, Animal and Plant Quarantine Agency , Anyang, South Korea .
authors.forename: Hee-Soo
authors.initials: HS
authors.lastname: Lee
authors.affiliation: 2 Avian Disease Division, Animal and Plant Quarantine Agency , Anyang, South Korea .
authors.forename: Min-Su
authors.initials: MS
authors.lastname: Kang
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001717:Birds / Q000382:microbiology*; D002645:Chickens / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D029968:Escherichia coli Proteins / Q000235:genetics; D008826:Microbial Sensitivity Tests / Q000379:methods; D010957:Plasmids / Q000235:genetics*; D015363:Quinolones / Q000494:pharmacology*; D056910:Republic of Korea
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D015363:Quinolones