Vibrio parahaemolyticus bacteria, 3D computer illustration based on scanning electron microscopy (SEM) imagery. This is a Gram- negative, rod-shaped, motile bacterium that is found in saltwater. Each cell has a single polar flagellum that is used for locomotion. V. parahaemolyticus is a major cause of seafood-borne gastroenteritis, caused by the consumption of raw or undercooked seafood. Less commonly, this organism can cause an infection in skin when an open wound is exposed to warm seawater.