the Pacific Oyster

This study is presented as a two part investigation to evaluate the survival and growth of pathogenic vibrios in estuarine waters, and to demonstrate the colonization of living oysters incubated in waters contaminated with V. vulnificus. V. cholerae, V. fluvialis and V. vulnificus were able to grow and multiply in estuarine water solutions, exhibiting 100 to 1,000 fold increases in sterile estuarine water. Regrowth was repressed in non-sterile estuarine water due to the presence of indigenous microbes. The three species of Vibrio exhibited an optimum salinity range of 6-10 0 /00, and growth occurred at temperatures of 15, 25 and 37°C, but was inhibited at 5°C. V. vulnificus was able to colonize living oysters within several hours after contaminating water with the pathogen. Storage of contaminated oysters at 5°C enabled the Vibrio to survive in the oyster tissue for up to twenty days. Several strains of V. vulnificus increased in cell numbers during storage at this temperature. All strains of V. vulnificus increased in cell number in oyster tissue upon storage for three to five days at 25°C, attaining an average of 109 Vibrio cells per gram of oyster tissue