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: Medicine
[{'content': 'What is the most likely cause of this finding in a man from Mexico who had a biopsy showing gram-negative bacilli? \nSelect and explain. \nA. Klebsiella rhinoscleromatis, B. Mycobacterium leprae, C. Acinetobacter baumannii, D. Treponema pallidum', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer A. Klebsiella rhinoscleromatisRhinoscleroma is a chronic bacterial infection that is typically caused by the gram-negative bacillus K. rhinoscleromatis.', 'role': 'assistant'}]