Genetic characteristics of antibiotic resistance genes in Vibrio cholerae isolated in Tra Vinh province

Abstract

Out of 25 Vibrio spp. strains isolated from the river, sea water and feed having origin from fish in Tra Vinh province in December, 2014, there were 6 strains classified as Vibrio cholerae strains and they were tested for antibiotic resistance with 8 antibiotics. By Kirby-Bauer method, the antibiotic resistance strains were determined, including 50% of the strains were resistant to streptomycin, 17% were resistant to ampicillin, 33% were resistant to tetracycline, 33% were resistant to trimethoprim-sulfamethoxazole and 67% were resistant to vancomycin. The PCR analysis results also showed that there were 2 out of 6 Vibrio cholerae strains containing antibiotic resistance tetA gene encoding for tetracycline resistance, the antibiotic resistance gene groups (blaSHV, aac (3) -IV and dhfrI) encoding for resistance to antibiotics: β-lactam, aminoglycosid, trimethoprim were not detected in this study.
The nucleotide sequence similarity level of the TestAF and TestAR genes of the isolated strains in this study in comparison with those of the other isolated strains in Thailand, Japan, China, Indonesia, Brazil and India was 97% with 10 strains; 96% with 01 strains and 94% with 02 strains. The result of phylogenetic tree analysis also showed close relationship of the strains carrying antibiotic resistance genes are always potential risks, easy to receive and transfer the antibiotic resistance genes from genetic factors, such as: plasmids, integrons, transposons. The antibiotic resistance mutation genes in V. cholerae, are always present in the environment and seafood.