This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti-Parasitic Drugs, Subject name: Pharmacology
[{'content': 'A patient was being treated with a drug that interferes with the activity of enzyme pyruvate ferredoxin oxidoreductase. Which of the following is the most likely organism causing infection in this patient? \nSelect and explain. \nA. Beef tapeworm, B. Whipworm, C. Cryptosporidium, D. Trypanosoma', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Pyruvate ferredoxin oxidoreductase (PFOR) enzyme dependent electron transfer is essential for anaerobic metabolism in many protozoa and bacterial species. The drug that acts by interfering with this reaction is nitazoxanide. It is the only drug available for cryptosporidiosis. It is also approved for treatment of Giardiasis.', 'role': 'assistant'}]