Research and characterization of pathogenic vibrios from bathing water along the Conero Riviera (Central Italy)

The occurrence and pathogenicity of vibrios in bathing water were investigated along the Conero Riviera (Adriatic Sea, Central Italy). Vibrio spp. enumeration was performed on thiosulfate-citrate-bile-salts-sucrose-agar by the membrane filter method, and identification was done through a biochemical protocol. All isolates were tested for the presence of cytotoxicity, protease, lipase, elastase, gelatinase, urease, haemolytic activity, ctx, tdh and trh genes by conventional methods. In all, 200 vibrios were isolated from 132 samples that were analysed. Vibrio harveyi and Vibrio alginolyticus were the species most frequently recovered. All strains were cytotoxic and some of them showed protease, gelatinase, lipase, elastase, urease and haemolytic activity. One isolate of V. alginolyticus and one of V. harveyi had the trh gene, while another strain of V. harveyi and one of Vibrio parahaemolyticus had the ctx gene. These results demonstrate the presence of potentially pathogenic vibrios in the Conero Riviera and the risk of infection due to bathing water exposure.