Review Question - QID 216734

A 31-year-old man and his wife present to the emergency department with a 1-day history of vomiting and diarrhea. They just returned home from a cruise vacation, during which they started having watery diarrhea on the last day of the cruise. They ordered different menu items over the course of the vacation and never stayed off the ship overnight. While being evaluated, the man experiences an episode of diarrhea as well as several episodes of vomiting. His temperature is 98.3°F (36.8°C), blood pressure is 110/80 mmHg, pulse is 104/min, respirations are 20/min, and oxygen saturation is 98% on room air. Physical exam reveals a non-distended non-tender abdomen. His cardiopulmonary exam is unremarkable. A stool sample does not have evidence of blood or fat. Which of the following organisms is the most likely etiology of this patient's symptoms?