This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'A patient of Acute lymphocytic leukaemia with fever and neutropenia develops diarrhoea after administration of amoxicillin therapy, which of the following organism is most likely to be the causative agent \nSelect and explain. \nA. Salmonella typhi, B. Clostridium difficile, C. Clostridium perfringens, D. Shigella flexneri', 'role': 'user'}, {'content': "Answer: B \nExplanation: Clostridium difficile causes acute colitis with bloody diarrhea and pseudomembranous colitis. A common cause of nosocomial diarrhea. The disease follows the use of broad-spectrum antibiotics like clindamycin, ampicillin, amoxicillin, or fluoroquinolones to which it is resistant. Exotoxin A and B involved in the pathogenesis. An oppounistic organism that causes disease only when the normal mechanism is altered. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 270", 'role': 'assistant'}]