Isolation and identification of pathogenic Vibrio parahaemolyticus from waters and coastal sediments of Caspian Sea (Gilan province, Iran) and investigation of its virulence genes

The purpose of this study was to determine the frequency of Vibrio parahaemolyticus and to identify pathogenic and non-pathogenic strains of this bacterium using a series of biochemical tests and polymerase chain reactions from the shores of the Caspian Sea (Gilan Province). The water and sediment samples of the Caspian Sea were collected from the depth of 30-50 and 10-20 cm respectively by aseptic method. Sampling date, sampling location, temperature, pH and salinity were measured. Isolation and identification of environmental isolates was done using standard methods in order to determine the genus and species using specific media such as thiosulfate citrate bile sucrose and Vibrio chrome agar. A total of 55 isolates were identified by biochemical, phenotypic and polymerase chain reaction tests. From the total of 55 cases of Vibrio parahemolyticus isolated, the frequency of tdh and trh genes was 1 case (1.8%) and 3 cases (5.4%) respectively. This study showed that Vibrio parahaemolyticus, which have pathogenic potential, should be continuously monitored as agents of contamination of coastal waters. The isolation of these species indicates a health warning for people who use raw seafood or are in direct contact with the waters of the Caspian Sea are in this area.