Antimicrobial resistance and multilocus sequence typing analysis of Vibrio parahaemolyticus from seafood in Chengdu

Abstract

Objective To find out the contamination, antimicrobial resistance, virulence gene distribution and genotyping of Vibrio parahaemolyticus in different kinds of marine products in Chengdu. Increase the basic data on the prevalence and risk assessment of foodborne Vibrio parahaemolyticus in Chengdu. Methods According to GB 4789.7-2013, suspected strains of Vibrio parahaemolyticus were isolated from different marine products and accurately identified by biochemical tests and 16S rDNA sequencing. The antimicrobial resistance test of the isolated strains was carried out by Kirby-Bauer disk diffusion method. Two virulence genes related to its pathogenicity were detected by polymerase chain reaction (PCR), and then the isolated strains were typed by multilocus sequence typing. Results A total of 104 strains of Vibrio parahaemolyticus were isolated from 380 seafood samples collected, with an overall detection rate of 27.4%. Antimicrobial resistance test showed that 97.1% (101/104) of the isolates had resistance, of which the drug resistance rate to ampicillin was the highest (95.2%, 99/104). The harboring rate of trh gene among the isolated strains was 12.5% (13/104), and was 0.1% (1/104) for tdh gene.104 isolates were divided into 38 ST types, of which ST1801, ST392 and ST413 were at high level. No epidemic clone group was found in the isolates. Conclusion There were differences in the contamination rate, antimicrobial resistance, and virulence genes distribution of Vibrio parahaemolyticus in different kinds of marine products, which might be related to the breeding environment and transportation conditions.

Keywords

• vibrio parahaemolyticus
• antimicrobial resistance
• virulence gene
• multilocus sequence typing