Potential sources of Clostridium difficile in human infection.

The view of Clostridium difficile infection as a hospital-acquired infection transmitted only by symptomatic patients is changing. Although C difficile is present in food for human consumption, food-borne infection caused by C difficile has never been confirmed. More information on the infective dose and the level of contamination is needed to determine the risk for food-borne exposure to C difficile in humans. The emergence of C difficile polymerase chain reaction (PCR) ribotype 078 in humans is epidemiologically linked to its presence in piglets and calves and their environment, suggesting zoonotic transmission.