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High prevalence of blaCTX-M group genes in Aeromonas dhakensis isolated from aquaculture fish species in South Korea.

Yi SW, Chung TH, Joh SJ, Park C, Park BY, Shin GW - J. Vet. Med. Sci. (2014)

Bottom Line: In the results, the bla(TEM-1) gene was harbored in all strains, whereas only 3 strains harbored bla(OXA) gene.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.

View Article: PubMed Central - PubMed

Affiliation: Bio-safety Research Institute and College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, 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.

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Phylogenetic identification of blaCTX-M-1-group genesequences resulting from blaCTX-M-positive strains. Theidentification was performed by alignments with major sequences belonging toblaCTX-M-1-group genes in GenBank (accession numbersare within parentheses). The branch numbers refer to the percentage confidence asestimated by a bootstrap analysis with 1,000 replications.
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fig_001: Phylogenetic identification of blaCTX-M-1-group genesequences resulting from blaCTX-M-positive strains. Theidentification was performed by alignments with major sequences belonging toblaCTX-M-1-group genes in GenBank (accession numbersare within parentheses). The branch numbers refer to the percentage confidence asestimated by a bootstrap analysis with 1,000 replications.

Mentions: In investigation of genetic background to β-lactam resistances, all of the 119 strainsharbored the blaTEM, and sequences of random PCR products had100% identity to gene encoding TEM-1-type β-lactamase (GenBank No. KJ933392). TheblaOXA gene was encountered in three strains: one A.allosaccharophila strain from pet fish and two A. caviae strainsfrom eel. In the case of blaCTX-M gene, prevalence of the geneshowed differences according to Aeromonas spp. and β-lactam resistancepatterns (Table 2). TheblaCTX-M genes were detected in 25 strains including 20 ofA. dhakensis (19 eel strains and 1 pet fish strain), 2 eel strains ofA. caviae and 3 eel strains of A. hydrophila. The PCRproducts were subjected to phylogenetic analysis by direct sequencing analysis using theprimer set for blaCTX-M consensus [18]. The constructed phylogenetic tree showed that 25blaCTX-M-positive strains were grouped with genes encodingCTX-M-1-group β-lactamases (Fig. 1Fig. 1.


High prevalence of blaCTX-M group genes in Aeromonas dhakensis isolated from aquaculture fish species in South Korea.

Yi SW, Chung TH, Joh SJ, Park C, Park BY, Shin GW - J. Vet. Med. Sci. (2014)

Phylogenetic identification of blaCTX-M-1-group genesequences resulting from blaCTX-M-positive strains. Theidentification was performed by alignments with major sequences belonging toblaCTX-M-1-group genes in GenBank (accession numbersare within parentheses). The branch numbers refer to the percentage confidence asestimated by a bootstrap analysis with 1,000 replications.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4300373&req=5

fig_001: Phylogenetic identification of blaCTX-M-1-group genesequences resulting from blaCTX-M-positive strains. Theidentification was performed by alignments with major sequences belonging toblaCTX-M-1-group genes in GenBank (accession numbersare within parentheses). The branch numbers refer to the percentage confidence asestimated by a bootstrap analysis with 1,000 replications.
Mentions: In investigation of genetic background to β-lactam resistances, all of the 119 strainsharbored the blaTEM, and sequences of random PCR products had100% identity to gene encoding TEM-1-type β-lactamase (GenBank No. KJ933392). TheblaOXA gene was encountered in three strains: one A.allosaccharophila strain from pet fish and two A. caviae strainsfrom eel. In the case of blaCTX-M gene, prevalence of the geneshowed differences according to Aeromonas spp. and β-lactam resistancepatterns (Table 2). TheblaCTX-M genes were detected in 25 strains including 20 ofA. dhakensis (19 eel strains and 1 pet fish strain), 2 eel strains ofA. caviae and 3 eel strains of A. hydrophila. The PCRproducts were subjected to phylogenetic analysis by direct sequencing analysis using theprimer set for blaCTX-M consensus [18]. The constructed phylogenetic tree showed that 25blaCTX-M-positive strains were grouped with genes encodingCTX-M-1-group β-lactamases (Fig. 1Fig. 1.

Bottom Line: In the results, the bla(TEM-1) gene was harbored in all strains, whereas only 3 strains harbored bla(OXA) gene.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.

View Article: PubMed Central - PubMed

Affiliation: Bio-safety Research Institute and College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, 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.

Show MeSH
Related in: MedlinePlus