title: Antimicrobial resistance and resistance genes in Escherichia coli strains isolated from commercial fish and seafood.
abstract: The purpose of this study was to investigate the antimicrobial resistance and to characterize the implicated genes in Escherichia coli isolated from commercial fish and seafood. Fish and seafood samples (n=2663) were collected from wholesale and retail markets in Seoul, Korea between 2005 and 2008. A total of 179 E. coli isolates (6.7%) from those samples were tested for resistance to a range of antimicrobial agents. High rates of resistance to the following drugs were observed: tetracycline (30.7%), streptomycin (12.8%), cephalothin (11.7%), ampicillin (6.7%) and ticarcillin (6.1%). No resistances to amikacin, amoxicillin/clavulanic acid and cefoxitin were observed. Seventy out of 179 isolates which were resistant to one or more drugs were investigated by PCR for the presence of 3 classes of antimicrobial resistance genes (tetracycline, aminoglycosides and beta-lactams), class 1, 2 and 3 integrons. Gene cassettes of classes 1 and 2 integrons were further characterized by amplicon sequencing. The tetracycline resistance genes tetB and tetD were found in 29 (41.4%) isolates and 14 (20%) isolates, respectively. The beta-lactam resistance gene, bla(TEM) was found in 15 (21.4%) isolates. The aminoglycoside resistance gene, aadA was found in 18 (25.7%) isolates. Class 1 integron was detected in 41.4% (n=29) of the isolates, while only 2.9% (n=2) of the isolates were positive for the presence of class 2 integron. Two different gene cassettes arrangements were identified in class 1 integron-positive isolates: dfrA12-aadA2 (1.8 kb, five isolates) and aadB-aadA2 (1.6 kb, four isolates). One isolate containing class 2 integron presented the dfrA1-sat-aadA1 gene cassette array. These data suggest that commercial fish and seafood may act as the reservoir for multi-resistant bacteria and facilitate the dissemination of the resistance genes.
authors.affiliation: Seoul Metropolitan Government Research Institute of Public Health and Environment, Gwacheon 427-070, Republic of Korea. dream21c@seoul.go.kr
authors.forename: Seung-Hee
authors.initials: SH
authors.lastname: Ryu
authors.forename: Seog-Gee
authors.initials: SG
authors.lastname: Park
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Choi
authors.forename: Young-Ok
authors.initials: YO
authors.lastname: Hwang
authors.forename: Hee-Jin
authors.initials: HJ
authors.lastname: Ham
authors.forename: Su-Un
authors.initials: SU
authors.lastname: Kim
authors.forename: Young-Ki
authors.initials: YK
authors.lastname: Lee
authors.forename: Moo-Sang
authors.initials: MS
authors.lastname: Kim
authors.forename: Geon-Yong
authors.initials: GY
authors.lastname: Park
authors.forename: Kyung-Sik
authors.initials: KS
authors.lastname: Kim
authors.forename: Young-Zoo
authors.initials: YZ
authors.lastname: Chae
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D005399:Fishes / Q000382:microbiology*; D005798:Genes, Bacterial; D032023:Integrons; D007723:Korea; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D017747:Seafood / Q000382:microbiology*; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams