Abstract
Two major problematic waterborne pathogens in coastal Gulf of Mexico include Vibrio vulnificus and Vibrio parahaemolyticus. We surveyed 44 locations in 7 major basins for the abundances of these species during a cool winter month, where water temperatures ranged 12.3 – 22.2oC. Viable Vibrio species were enumerated in water column (n=44), sediments (n=43), and invertebrate biofilms (n=14) employing a chromogenic agar assay. In surface waters, V. vulnificus outnumbered V. parahaemolyticus by about 5-fold in most samples and was detected in 37 of 44 water samples, with maximum levels of 3,556 cells/mL. V. parahaemolyticus was only detected in 15 of 44 water samples, but with a maximum concentration of 8,919 cells/mL. On average, V. vulnificus outnumbered V. parahaemolyticus by 18-fold in all sediments. In all but one sediment sample, V. vulnificus was detected, with concentrations from 121 to 607,222 cells/mL. In contrast, V. parahaemolyticus were only detected in 33 of the 43 sediment samples, where concentrations ranged from 28 to 77,333 cells/mL. Of note is the positive significant correlation between V. vulnificus abundances in sediments and the salinity observed in the water column at depth (R=0.3887, p< 0.05), where bottom water salinities ranged from 2 to 28 PSU. Abundances in biofilms, collected from oyster or barnacle shells or from invertebrate worms found in sediment samples, were also evaluated. In comparing biofilm abundances on different types of shells, there was not a statistical difference between oysters (n=5) and barnacles (n=7) for V. vulnificus (p=0.675) or V. parahaemolyticus (p=0.628). This is the first study of the Pensacola Bay System enumerating viable Vibrio abundances and assessing ecological factors affecting their distributions in these 7 basins.
