Which is the most common cause of bacterial enteritis in the United States?

• A. E. coli
• B. Vibrio cholerae
• C. Staph aureus
• D. Campylobacter jejuni

Answer: (D)

Campylobacter jejuni is the leading cause of bacterial enteritis in the United States. Infections typically come from undercooked poultry, unpasteurized milk, or contaminated water, and present with sudden abdominal cramps, fever, and diarrhea that can be watery or bloody. The illness is usually self-limited, resolving within a week or so. Lab wise, Campylobacter is a curved Gram-negative rod that grows best in microaerophilic conditions at around 42°C, which helps distinguish it in cultures. It’s also tied to notable but less common complications, like reactive arthritis and, rarely, Guillain-Barré syndrome due to immune cross-reactivity. Other options either represent specific scenarios (like traveler's diarrhea from certain E. coli strains) or cause different syndromes (cholera from Vibrio cholerae, food-poisoning from Staphylococcus aureus), and are not the most common cause of bacterial enteritis in the US.