ISOLATION OF VIBRIO SPECIES AND POTENTIAL ANTAGONISTS FROM OYSTER SPECIES FROM DIFFERENT GEOGRAPHICAL REGIONS

Vibrio as a genus is phenotypically diverse causing disease in marine life as well as in humans.  Vibrio spp. have been isolated worldwide, are found in coastal waters and estuaries, and are the most common cause of disease associated with the culture of oyster and other bivalves in hatcheries and in nurseries. Juvenile oysters are most susceptible to vibriosis while adult bivalves do not suffer high mortalities when challenged with Vibrio spp.  Not all Vibrio spp. found in oysters and marine life are pathogenic. Moreover, non-pathogenic bacteria found in the marine environment have the potential to be antagonists against pathogenic bacteria.  Vibriosis can be catastrophic to the aquaculture industry.  Finding a biological antagonist that has efficacy against Vibrio spp. isolated from different geographical regions would be a significant find. In this study, we collected oysters grown in different locations in the United States. Oysters were ground and plated on Thiosulfate-citrate-bile salts-sucrose agar (TCBS) for Vibrio isolation and on Tryptic Soy Agar (TSA) for identification of potential antagonists.  Interactions were examined between isolated Vibrio spp. and potential antagonists using agar inhibition techniques. A subset of the data is summarized (Table 1).

One isolate had activity against 4 different Vibrio spp. from the two geographical regions tested.  Additional isolates were identified that were active against one or two Vibrio. RA34 will be tested against additional Vibrio spp. from other regions to determine its probiotic potential.