This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Human Immunodeficiency Virus, Subject name: Microbiology
Most common agent causing tuberculosis in AIDS patient in tropical countries is: 
Select and explain. 
A. Mycobacterium tuberculosis, B. Mycobacterium intracellulare1997, C. Mycobacterium parvum, D. Mycobacterium atypical
A: Mycobacterium tuberculosis
Answer: A: Mycobacterium tuberculosis 
Explanation: Ans. is 'a' i.e., Mycobacterium tuberculosis (Ref: Ananthanarayan, 9th/e, p. 576 and 8th/e, p. 575)Common pathogens causing T.B. in AIDS patients are M. tuberculosis and M. avium intraceliulare. In developing countries, the most important pathogen is M. tuberculosis, with many strain being multidrug resistant.