Campylobacter jejuni (CAM-puh-low-back-ter juh-JUNE-eye) is one of the most common causes of food poisoning in the United States. The vast majority of cases occur as isolated events, not as part of recognized outbreaks. Campylobacter coli is a Gram-negative, microaerophilic, nonendospore-forming, S-shaped bacterial species within genus Campylobacter.