Detection of Virulence Determinants and Antimicrobial Susceptibility of Vibrio species Isolated from Raw Fish Markets

Abstract

Vibriosis is a major cause of death in farmed aquaculture systems around the world caused by an infection with Vibrio spp. This study was performed to detect the prevalence of pathogenic Vibrio species from various fish species (n=200) collected from Port-Said fish markets as well as to assess the antimicrobial resistance profile and virulence determinants of the isolated Vibrio. Fish samples were inoculated onto Vibrio-selective medium (TCBS), and phenotypically identified using biochemical tests and the suspected isolates were then confirmed by PCR targeting collagenase gene followed by sequencing of the amplified gene. Disc diffusion method was used to investigate the antimicrobial susceptibility of the isolated strains as well as the virulence determinants were detected by PCR assay. Out of 200 fish samples, 80 Vibrio isolates including V. parahaemolyticus (22 /80) and V. alginolyticus (58 /80) were recovered. While V. vulnificus couldn’t be identified. Vibrio isolates displayed high resistance to beta-lactams antimicrobials and a lower resistance were displayed against tetracycline, quinolones and carbapenems. Additionally, tlh gene was present in all V. parahaemolyticus isolates, while the tdh gene was present in 27.1% (6/22). In conclusion, the results of this study provide information on the hazards that certain fish and shellfish could bring by transferring virulent and genetic resistance of V. parahaemolyticus and V. alginolyticus to people through food., therefore, consumers should be more alert, prepare food properly, and avoid undercooked or cross-contaminated fish.