title: High prevalence of blaCTX-M group genes in Aeromonas dhakensis isolated from aquaculture fish species in South Korea.
abstract: The prevalence of resistant genes against β-lactams in 119 Aeromonas strains was determined. A large number (99.2%) of the present fish strains were resistant to one or more β- lactams including ceftiofur, amoxicillin-clavulanic acid, ampicillin, piperacillin and cefpodoxime. Among antibiotic resistance phenotypes, the simultaneous resistance to all β-lactams occurred in 25.2% (n=30) of all strains, which consisted of 18 strains of A. dhakensis, 8 strains of A. caviae, 2 strains of A. hydrophila and only one strain of A. veronii. For exploring genetic background of the antibiotic resistances, multiple PCR assays were subjected to detect β-lactamase-encoding genes, bla(TEM), bla(OXA-B) and bla(CTX-M). In the results, the bla(TEM-1) gene was harbored in all strains, whereas only 3 strains harbored bla(OXA) gene. In the case of bla(CTX-M) gene, the gene was detected in 21.0% (25 out of 119) of all strains, which countered with 80% (20 out of 25) of A. dhakensis, 8% (2 out of 25) of A. caviae and 12% (3 out of 25) of A. hydrophila. In addition, most of the bla(CTX-M) positive strains showed simultaneous resistance to all β-lactams (18 out of 30 strains). In sequence analysis for bla(CTX-M) genes detected, they were CTX-M group 1-encoding genes including bla(CTX-M-33) from 3 eel strains of A. dhakensis. Therefore, A. dhakensis obtained from cultured fish could represent a reservoir for spreading genes encoding CTX-M group 1 enzymes and hence should be carefully monitored, especially for its potential risk to public health.
authors: Bio-safety Research Institute and College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, South Korea.
authors: Seung-Won
authors: SW
authors: Yi
authors: Tae-Ho
authors: TH
authors: Chung
authors: Seong-Joon
authors: SJ
authors: Joh
authors: Chul
authors: C
authors: Park
authors: Byoung-Yong
authors: BY
authors: Park
authors: Gee-Wook
authors: GW
authors: Shin
mesh_terms: D000333:Aeromonas / Q000235:genetics*; D000818:Animals; D017756:Aquaculture; D001483:Base Sequence; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005393:Fish Diseases / Q000453:epidemiology* / Q000382:microbiology*; D005399:Fishes; D008969:Molecular Sequence Data; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001618:beta-Lactamases
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