A patient develops severe, watery diarrhea, fever & abdominal pain. Clostridium difficile infection in the gut is confirmed. The antimicrobial therapy for this antibiotic-associated pseudomembranous colitis is:

Correct Answer: D

Rationale: Metronidazole or vancomycin treats C. difficile colitis; vancomycin is preferred for severe cases, and both are effective.

Correct Answer: D

Rationale: Penicillins and sulfonamides frequently cause hypersensitivity reactions (e.g., rash, anaphylaxis), unlike erythromycin.

Correct Answer: B

Rationale: Cefoperazone inhibits vitamin K-dependent clotting factors, increasing bleeding risk with warfarin.

Correct Answer: B

Rationale: Metronidazole disrupts DNA in anaerobes, unlike ciprofloxacin (aerobic gram-negatives), rifampicin (RNA polymerase), or clinafloxacin (broad-spectrum).

Correct Answer: B

Rationale: Imipenem is broad-spectrum, protected by cilastatin, and β-lactamase resistant, but it’s not preferred in penicillin-allergic meningitis patients (meropenem is safer).