This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection, Subject name: Pediatrics
Which of the following is the drug of choice for Pseudomembranous colitis: 
Select and explain. 
A. Oral vancomycin, B. Erythromycin, C. Azithromycin, D. Meropenem
A: Oral vancomycin
Answer: A: Oral vancomycin 
Explanation: Ans. A. Oral vancomycinAnti-bodies can lose watery stools by altered bacterial flora or bloody stools secondary to Clostridium difficult overgrowth and pseudomembranous colitis (PMC). Stopping the offending agent is often enough. If suspicion of PMC is present then stool for toxin assay and sigmoidoscopy is required for confirmation. Metronidazole or oral vancomycin is the drug choice for PMC.