High Prevalence of BlaCTX-M Group Genes in
Aeromonas dhakensis Isolated from Aquaculture Fish Species in South
Korea |
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| Authors: | Seung-Won YI Tae-Ho CHUNG Seong-Joon JOH Chul PARK Byoung-Yong PARK Gee-Wook SHIN |
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| Institution: | 1)Bio-safety Research Institute and College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, South Korea;2)Department of Animal Science, Joongbu University, Chungnam 312-702, South Korea;3)Animal, Plant and Fisheries Quarantine and Inspection Agency, Anyang 480-757, South Korea |
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| 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, blaTEM,
blaOXA-B and blaCTX-M. In the
results, the blaTEM-1 gene was harbored in all strains,
whereas only 3 strains harbored blaOXA gene. In the case of
blaCTX-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
blaCTX-M positive strains showed simultaneous resistance to
all β-lactams (18 out of 30 strains). In sequence analysis for
blaCTX-M genes detected, they were CTX-M group 1-encoding
genes including blaCTX-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. |
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| Keywords: | Aeromonas aquariorum Aeromonas dhakensis aquaculture β -lactams blaCTX-M-1 group |
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