Detection of antibiotic resistance and virulence genes of Vibrio strains isolated from ready-to-eat shrimps in Delta and Edo States, Nigeria.

Abstract

The current study was conducted to determine the incidence, antibiotic resistance and virulence genes of Vibrio strains isolated from ready-to-eat shrimps in Edo and Delta States, Nigeria. A total of 1440 ready-to-eat shrimp samples were obtained from open markets from November 2016 to October 2017 and analysed using standard culture-based procedures. Overall, our result showed that the ready-to-eat shrimp samples had high mean aerobic mesophilic bacterial count between 3·543 and 7·489 log10 CFU per gram. Vibrio cell densities ranged between 0·663 and 6·761 log10 CFU per gram. From the total samples, 1343/1440 (93·3%) were positive for Vibrio species where 120 Vibrio isolates were randomly selected and confirmed using genus- and species-specific PCR approach. The PCR identification revealed the presence of Vibrio parahaemolyticus 46 (38·33%), Vibrio vulnificus 14 (11·67%), Vibrio fluvialis 12 (10%), Vibrio alginolyticus 8 (6·67%), Vibrio cholerae 2 (1·67%), Vibrio mimicus 10 (8·33%), Vibrio harveyi 3 (2·5%) and other Vibrio sp. 25 (20·83%). All Vibrio isolates were sensitive to colistin and gentamycin with varying percentage of resistance to other antibiotics used in the study. Multiple antibiotic-resistant (MAR) index ranged from 0·08 to 0·83. The tcp, tdh and trl virulence genes were identified in 95 (79·2%), 92 (76·7%) and 95 (79·2%) of the examined isolates respectively. Antibiotic-resistant genes also revealed the presence of class 1 integrase 75 (62·5%), sul2 87 (72·5%), strB 94 (78·3%) and catB3 68 (56·7%). Our findings revealed that the ready-to-eat shrimps may serve as potential reservoirs and medium in the dissemination of prospective MAR pathogens to the consumers and thus constitute a potential risk to public health. The findings from this study represent the first comprehensive report of Vibrio isolates from ready-to-eat shrimps in Edo and Delta States, Nigeria. Incessant monitoring of Vibrio strains and their predisposition to antimicrobials is a necessity to guarantee seafood safety and guarantee the best treatment regimen for patients with gastroenteritis.