Investigating Environmental Parameters, Total Bacteria and Vibrio spp. in Slaughter Beach, Delaware

Abstract

Investigating Environmental Parameters, Total Bacteria and Vibrio spp. in Slaughter Beach, Delaware Devotha Tumushimiyimana1, Rosemary Ebirim2, Michael Watson3, Gary Richards3, Ph.D., Wilbert Long1, Ph.D, and Gulnihal Ozbay1,2, Ph.D. 1Food Science and Biotechnology Graduate Program, Human Ecology Department, Delaware State University, Dover, DE 2Department of Agriculture and Natural Resources, Delaware State University, Dover, DE 3USDA-ARS, Center of Excellence, Delaware State University, Dover, DE Vibrio are members of the Vibrionaceae family are Gram- negative rod -shaped heterotrophic bacteria that are present in diverse array of aquatic environments including oligohaline, and polyhaline water. Vibrio species present in the aquatic environment common to human pathogens are V. vulnificus, V. parahaemolyticus, and V. cholera, and cause wound infections, and gastro- intestinal disease. Other vibrio such as V. coralliilyticus, and V. tubiashii have been known as shellfish pathogens. This research is seeking to know if there are potential risks such as Vibrio spp. for juvenile oysters to grow in Slaughter Beach, if water from Slaughter Beach is suitable to establish an oyster production hatchery, and if Slaughter Beach has potential risks for human pathogenic Vibrio. The four species that are being studied include V. vulnificus, V. parahaemolyticus, V. coralliilyticus, and V. tubiashii. The objectives of this study are to evaluate total Vibrio vulnificus, V. parahaemolyticus, V. coralllilyticus, and V. tubiashi in seawater and oysters collected from Slaughter Beach, Delaware, and to determine relationship between water quality and Vibrio spp. level in seawater, and oysters collected from Slaughter Beach, Delaware. Water samples are collected from two different sites (Cedar Creek and Boat ramp) from June to July 2021 at high and low tides in Slaughter Beach, Delaware. The samples were collected bimonthly. A YSI-556 multiprobe system is used to monitor physical water parameters (Temperature (°C) Salinity (g/L) Conductivity (S/m), pH, Dissolved Oxygen (mg/L), Dissolved Oxygen (%) while chemical water quality parameters are monitored using YSI 9500 Photometer. Turbidity and Total Chlorophyll-a are monitored using a Global Water WQ770 turbidimeter and Turner Design AquaFlor Fluorometer, respectively. Vibrio are monitored by Thiosulfate Citrate Bile Salts Sucrose (TCBS) and Luria Broth (LB). The 100 microliters of seawater are inoculated at 26°C and 37°C, and isolated colonies are re-inoculated on LB agar, and stored for later 16Sr RNA Sequencing. Cedar Creek demonstrated high amounts of Vibrio spp. with high levels of salinity and temperature to both tides from June to July compared to the Boat ramp site. The Boat ramp site demonstrated high turbidity at high and low tides from June to July. This project is currently ongoing and further research is being conducted on seawater and oysters collected on Slaughter Beach, Delaware to have better understanding of the areas for potential oyster culture. Keywords: Vibrio, water quality, Eastern oyster, Vibrio vulnificus, Vibrio parahaemolyticus, Vibrio coralliilyticus, Vibrio tubiashii Acknowledgements: I acknowledge USDA NIFA Capacity Building Grant Award# 2016-06642 for funding my project as part of the student professional growth and my research, Faculty advisor Dr. Gulnihal Ozbay for providing this opportunity to learn from her.