Oysters play a significant role in nutrient cycling by filtering large volumes of seawater on a daily basis. This filtration of water results in the removal of sediments, bacteria, and nutrients from the water column and adds nutrients to the bethos. In addition, this leads to the bioaccumulation of different types of microorganisms in oysters such as Vibrio spp. Enterobacteriaceae and E. coli. Vibrio spp. present in marine environments common to human pathogens includes Vibrio vulnificus , Vibrio parahaemolyticus , and Vi. cholera, which may cause wound infections and gastrointestinal illnesses . Other Vibrio spp. such as Vibrio coralliilyticus and Vibrio tubiashii are known as shellfish pathogens. Enterobacteriaceae is a large, heterogeneous group of gram-negative rods. High level of human sewage disposed into coastal waters resulting in an increase in Enterobacteriaceae pathogens in these waters, hence a higher occurrence of food-borne disease from shellfish. Slaughter Beach, Delaware has been considered as a potential area to establish an oyster hatchery . However, total bacteria, Vibrio spp., E. coli , and Enterobacteriaceae levels remain unknown in seawater and oysters in S laughter Beach . Additionally, seawater quality may influence oyster larval production , especially Vibrio spp. targeting oyster larvae. The aims of this study were to investigate and evaluate V ibrio spp ., Enterobacteriaceae , and E. coli in seawater and oysters collected from Slaughter Beach, Delaware and d etermine relationship between water quality and level of total bacteria, total V ibrio spp., and Enterobacteriaceae levels in oysters and seawater collected from Slaughter Beach, Delaware.
Water and oyster samples were collected twice a month from the three different sites in Slaughter Beach, Delaware from June to November 2021 at high and low tides for water and low tide only for oysters. A YSI -556 multiprobe system was used to monitor physical water parameters while chemical water quality parameters were monitored using YSI 9500 Photometer. Vibrio spp. were monitored by using Thiosulfate Citrate Bile Salts Sucrose (TCBS). Isolated colony were re- inoculated on L uria Broth (LB) , then later, was picked to 4-5 ml of LB broth and incubated at the required temperature, at 250 rpm for about 3-4 hours. 30% glycerol stock was prepared by adding 700 µl of the culture to 300 µl glycerol, in a cryotube and then freeze for 16Sr RNA. Trypticase S oy Agar, MacConkey Agar, Luria Broth were used to monitor for total bacteria, Enterobacteriaceae and Escherichia coli, respectively. Based on the preliminary data, water quality parameters are found similar at all three sites, while Vibrio spp., E. coli , and Enterobacteriaceae levels are much higher on site two where the creek meets with Delaware Bay with 69 CFU /100ul, 77 CFU /100ul and 55 CFU /100ul , respectively. Vibrio levels have also changed as results of rains. T his is an ongoing project and further research results will be presented.