Environmental Predictors of Pathogenic Vibrios in South Florida Coastal Waters

In 2007, diseases caused by Vibrio vulnificus and other Vibrio species became nationally notifiable in the United States because of the potential severity of bloodstream infections. Direct contact of open wound with seawater and the ingestion of contaminated oysters are the principal modes of transmission. Presently, no clear environmental predictors of oyster contamination are known. This study is the first to report an apparent association between rainfall and Vibrio counts at five South Florida beaches. Using multiple regression and ANOVA, the relationship between Vibrio populations and various environmental factors were examined. Vibrio counts ranged from 135 CFU/100 mL at Hollywood Beach to 186,000 CFU/100 mL at North Miami Beach. Vibrio vulnificus and parahemolyticus were detected (less than 1% of all identified isolates) at two and four beaches respectively. Temperature and rainfall dates were the most significant correlates of the incidence of pathogenic Vibrio species.