Vibrio parahaemolyticus in seafood - associated outbreaks

Abstract

Among the 30 species of the genus Vibrio, only 13 of them are pathogenic to humans. All pathogenic vibrios have been reported to cause foodborne diseases, although V. parahaemolyticus is considered the most important pathogenic Vibrio. V. parahaemolyticus is a halophilic bacterium that occurs naturally in aquatic environments worldwide. The pathogen caused sporadic diarrhoea mainly associated with the consumption of raw or undercooked seafood up to recent years. Since 1996, the incidence of V. parahaemolyticus infections has increased dramatically. V. parahaemolyticus is the leading cause of seafood-associated bacterial gastroenteritis in the United States and of the half foodborne outbreaks in some Asian countries. This increase in incidence has been related to the emergence of the O3:K6 serovar. The pathogenic V. parahaemolyticus strains can produce a thermostable direct hemolysin or a thermostable direct hemolysin-related hemolysin, which are encoded by the tdh and trh genes, respectively. Vibrio parahaemolyticus has not been included in the microbiological criteria of E.U. Food legislation, probably because the risk by this pathogen was considered rather low in Europe. However, climate changes favour the growth of the pathogen in seawater. Recent studies in Spain and France have shown that V. parahaemolyticus infections from seafood consumption have been increased. The emergence of the pathogen in Europe is of public health concern and emphasizes the importance of microbiological surveillance and control programs for V. parahaemolyticus.