Virulence of Vibrio species isolated from some types of fish and shellfish

Vibrio species. are microbial foodborne pathogens with high public health hazards. Pathogenicity of Vibrio species. is encoded by a wide spectrum of virulence factors. This work was conducted to isolate and identify Vibrio species. from 150 fish and shellfish samples sold in Sohag markets and to determine the prevalence of Vibrio species. and their virulence genes by molecular techniques. Vibrio species. were isolated from 40% of the examined samples. Bacteriological and biochemical investigations showed that the highest rate of Vibrio spp. recovered from fish and shellfish was Vibrio. mimicus (43.3%) followed by V. vulnificus (16.7%), while the least percentage was V. anguillarium (1.7%). Samples were amplified by PCR technique for more accurate identification; all isolates were positive to 16S rRNA specific for Vibrio spp., all (7) isolates of V. parahemolyticus were positive for toxR, trh , while tdh gene was not identified in any of V. parahemolyticus isolates. sodB gene of V. cholerae was found in all four tested isolates while ctxAB and ompW genes were seen only in three isolates. All the identified isolates of V. mimicus encode sodB gene. hsp60 specific for V. vulnificus was detected in all isolates. Fish and shellfish in Sohag city were highly contaminated with Vibrio spp. causing a potential health hazard. PCR techniques represent a quick, accurate, and reliable method for detection of virulence genes of Vibrio spp. Strict infection control and hygienic measures should be applied at fish farms and markets to minimize food contamination with Vibrio spp.