Question

A 25-year-old man presents to the clinic complaining of abdominal cramping and diarrhea that began 4 days ago. He reports that the diarrhea was initially watery but has become frankly bloody over the past 24 hours. He does not recall having a fever. Five days prior to symptom onset, he attended a neighborhood barbecue where he consumed hamburgers. His temperature is $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure is $118/76\text{ mmHg}$, and heart rate is $88/\text{min}$. Abdominal examination reveals hyperactive bowel sounds and diffuse, mild tenderness without guarding or rebound. Laboratory studies show a leukocyte count of $10,500/\text{mm}^3$, hemoglobin of $14.2\text{ g/dL}$, platelet count of $220,000/\text{mm}^3$, and serum creatinine of $0.9\text{ mg/dL}$. Rapid stool enzyme immunoassay is positive for Shiga toxin. Which of the following is the most appropriate next step in management?