Theses and Dissertations

Issuing Body

Mississippi State University


Silva, Juan L.

Committee Member

Kim, Taejo

Committee Member

Schilling, M Wes

Date of Degree


Document Type

Graduate Thesis - Open Access


Food Science and Technology

Degree Name

Master of Science (M.S.)


College of Agriculture and Life Sciences


Department of Food Science, Nutrition and Health Promotion


Vibrio parahaemolyticus (Vp) infection is commonly caused by the consumption of raw or undercooked shellfish. Raw oysters are associated with most Vp outbreaks. Pathogenic Vp express thermostable-direct hemolysin (tdh) and to some extent thermostable-related hemolysin (trh). Additionally, some pathogenic Vp express urease (uh). The objectives of this work were to discern any relationships between urease (uh) expression, tdh/trh expression, and hemolytic activity in pathogenic and non-pathogenic clinical strains, and to compare urease, motility, tdh/trh expression, and hemolytic activity in raw oyster isolates. This information would determine if urease could be used as a biomarker to detect pathogenic Vp. About 80% of pathogenic strains were uh+ and all non-pathogenic strains were uh-. Two oyster samples were uh+ and no tdh or trh was detected in raw oyster strains.