VIBRIO PARAHAEMOLYTICUS. VIBRIO PARAHAEMOLYTICUS This scanning electron micrograph (SEM) depicts a Vibrio parahaemolyticus bacterium, Mag. 21851x. Vibrio parahaemolyticus is a bacterium in the same family as those that cause cholera. It lives in brackish saltwater, and causes gastrointestinal illness in humans. V. parahaemolyticus is a halophilic, or salt-requiring organism, naturally inhabiting coastal waters in the United States and Canada, and is present in higher concentrations during su