Bacterial Infections USMLE Step 1 Practice Question
A 66-year-old woman hospitalized for pneumonia received clindamycin therapy. Five days into treatment, she develops watery diarrhea, lower abdominal cramping, and fever (38.5°C). Vital signs show HR 98/min, BP 128/82 mmHg, RR 18/min. Laboratory studies reveal WBC 14,500/μL with left shift. Colonoscopy demonstrates yellow-white plaques overlying inflamed colonic mucosa. She denies recent antibiotic use prior to hospitalization. Which organism is most likely responsible for these findings?
Answer choices
- ABacillus cereus
- BVibrio cholerae
- CClostridioides difficileCorrect answer
- DEscherichia coli
- EClostridium perfringens
- FStaphylococcus aureus
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