Which organism is an important cause of food poisoning?

• A. Bacteroides fragilis
• B. Campylobacter ureolyticus
• C. Clostridium perfringens
• D. Clostridium histolyticum

Answer: (C)

The important concept here is toxin-mediated food poisoning from cooked meat dishes. Clostridium perfringens is well known for causing this type of illness because it produces an enterotoxin in the small intestine after large numbers of ingested bacteria multiply in cooked foods that have cooled or been kept warm for too long. The illness typically begins 6–24 hours after eating and presents with abrupt abdominal cramps and watery diarrhea, often without fever, usually lasting about a day. Foods implicated are often meat or poultry dishes, gravies, or stews that have been cooked in bulk and held at warm temperatures.

Other organisms listed are not classic food-poisoning culprits in the same way. Bacteroides fragilis is part of normal gut flora and more commonly associated with intra-abdominal infections rather than foodborne illness. Campylobacter ureolyticus, while capable of causing gastroenteritis, is discussed mainly as a cause of diarrheal illness from contaminated poultry or water, not the introductory toxin-mediated food poisoning characteristic of this question. Clostridium histolyticum is known for its enzymatic activity and has different clinical associations, not the typical food-poisoning syndrome described here.

So, the organism that best fits as an important cause of food poisoning due to a potent enterotoxin produced in contaminated food is Clostridium perfringens.