USMLE Step 2 Antibiotics And Treatments Practice Exam

Pseudomembranous colitis is primarily caused by an overgrowth of Clostridium difficile, often as a result of antibiotic use that disrupts normal gut flora. Clindamycin is particularly notorious for this side effect because it is highly effective against anaerobic bacteria, which can lead to an imbalance in the gut microbiota when it suppresses non-pathogenic species. Once the normal flora is disrupted, C. difficile can thrive, producing toxins that lead to colitis. While other antibiotics such as amoxicillin and vancomycin can also be associated with C. difficile infection, clindamycin is one of the most frequently cited in clinical literature and practice guidelines as a common culprit. Azithromycin, on the other hand, is less frequently linked to this condition. Therefore, clindamycin's strong association with pseudomembranous colitis makes it the correct answer to the question regarding which antibiotic is commonly associated with causing this condition.