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
What is the most likely cause of this finding in a man from Mexico who had a biopsy showing gram-negative bacilli? 
Select and explain. 
A. Klebsiella rhinoscleromatis, B. Mycobacterium leprae, C. Acinetobacter baumannii, D. Treponema pallidum
A: Klebsiella rhinoscleromatis
Answer: A: Klebsiella rhinoscleromatis 
Explanation: Answer A. Klebsiella rhinoscleromatisRhinoscleroma is a chronic bacterial infection that is typically caused by the gram-negative bacillus K. rhinoscleromatis.