Pathogenic vibrios and food sanitation of marine products

Abstract

Bacteria of the genus Vibrio are normal habitants in an aquatic environment such as river, estuarine, coastal and sea water, but include some species pathogenic for human. Currently 37 species are reported in the genus Vibrio, and 11 species in the genus Vibrio are recognized to be pathogenic for human. Of these pathogenic species, V. cholerae is well known as pathogen of epidemic cholera, and V. parahaemolyticus is the most important food poisoning bacterium in Japan. V. cholerae is serologically classified into two groups, V. cholerae Ol and non-Ol, namely NAG vibrio. V. cholerae Ol is an actual cholera vibrio causing epidemic cholera, characterized by severe watery diarrhea caused by cholera toxin. In the humen history, there were 7 worldwide cholera pandemics. On the other hand, some strains of non-Ol also cause diarrhea, but the symptoms are not so severe and not contagious. Therefore, non-Ol is defined as a food poisoning bacterium. In recent years, 40 to 60% of the food poisoning outbreaks are due to V. parahaemolyticus. V. mimicus and V. fluvialis are also recognized as food poisoning bacteria. In addition to these diarrhogenic vibrios, significance of V. vulnificus as a pathogen of opportunistic infection is suggested recently, because the vibrio occasionally causes fatal septicemia to aged patients having underlying disease, such as hepatic dysfunction. Sea foods in markets are frequently contaminated with V. parahaemolyticus or V. vulnificus in summer season, and V. cholerae non-Ol and V. mimicus are universal inhabitants in fresh or brackish water regions. Thus, the pathogenic vibrios are important bacteria in food sanitation control.