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Question 17#

A family of four presents to the emergency room with sudden-onset abdominal cramps, nausea, and vomiting. None of them has fever or diarrhea. Four hours earlier, they had lunch at a road side restaurant. They ate a variety of grilled meats, fried rice, and seasoned vegetables. Symptoms resolved in 24 hours. Which organism is most likely responsible for this outbreak?

A) Bacillus cereus
B) Campylobacter jejuni
C) Salmonella enterica
D) Giardia lamblia
E) Yersinia enterocolitica

Correct Answer is A


The symptoms and time of onset after consumption of contaminated food determine the agents likely responsible for foodborne illness. Nausea and vomiting within 1 to 6 hours of consumption of food are caused by preformed toxins of B cereus and S aureus or heavy metals like copper or zinc. Abdominal cramps and diarrhea that develop more than 8 hours after a meal are caused by C jejuni, E coli, Salmonella, Shigella, and Vibrio parahaemolyticus. It takes more than 8 hours for the bacteria to proliferate in the gut and initiate the infection. Watery diarrhea can also be caused by enterotoxigenic E coli, V cholerae, and Norovirus. Yersinia enterocolitica can cause fever and abdominal cramps without diarrhea—a presentation closely resembling acute appendicitis. Cryptosporidiosis, cyclosporiasis, and giardiasis cause diarrhea that can persist for 1 to 3 weeks. The onset of symptoms in these parasitic diseases is more gradual; fever and systemic toxicity are absent.