Efficiency of real-time polymerase chain reaction assay to detect Vibrio vulnificus in seawater

The growth of Vibrio vulnificus in an enriched culture of seawater during the summer in Japan was monitored by a plating technique used as the culture method and a real-time polymerase chain reaction (PCR) assay as the molecular method. V. vulnificus was detected by the real-time PCR assay in the samples of August and September but not by the culture method. Vibrio parahaemolyticus, however, was detected among all of the samples with both the culture method and real-time PCR assay. In the analysis of the bacterial populations in enrichment culture, it was demonstrated that the growth of V. vulnificus on agar media was inhibited by the rapid growth of V. parahaemolyticus after 4 h of incubation and the 100 times larger initial populations of bacteria other than V. vulnificus and V. parahaemolyticus. These findings demonstrate that V. vulnificus detection by culture methods is a failure, and molecular methods are effective and detect V. vulnificus accurately.