The use of multiple typing methods allows a more accurate molecular characterization of Vibrio parahaemolyticus strains isolated from the Italian Adriatic Sea

Vibrio parahaemolyticus is a natural inhabitant of marine environments and constitutes part of the autochthonous microbial communities, but is also associated with human gastroenteritis, wound infections and septicemia. Recently, a number of clinical cases of infection due to ingestion of seafood contaminated with V. parahaemolyticus and potentially pandemic marine strains isolated from water and plankton have been reported in Europe. To identify the source of virulent strains and to analyze the possible persistence, in time and space, of particular clones, the molecular typing of Vibrio strains is of high epidemiological interest. In this study, we applied pulsed-field gel electrophoresis and two PCR-based techniques (enterobacterial repetitive intergenic consensus- and repetitive extragenic palindromic-PCR) to establish the DNA fingerprints for the analysis of genetic variability among the environmental V. parahaemolyticus strains isolated in the area of the Venetian Lagoon. A temporal distribution of the environmental strains in the studied geographical area and, in some cases, a strong association between a certain genetic profile and a specific source have been evidenced. A number of genetic clusters/clones seem to persist over time, reappearing in the marine environment for subsequent months and also at a 1-year gap. The use of multiple typing methods allowed a more accurate characterization of the environmental strain genetic profiles and the identification of clones hardly revealed through common techniques.