This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
All the following are true of Tuberculosis except ? 
Select and explain. 
A. For sputum to be positive, (A194) bacilli should be > 1, B. Niacin test differentiates M. tuberculosis and M. bovis, C. Pathogenicity to rabbits differentiates M. tuberculosis and M. bovis, D. All
C: Pathogenicity to rabbits differentiates M. tuberculosis and M. bovis
Answer: C: Pathogenicity to rabbits differentiates M. tuberculosis and M. bovis 
Explanation: Ans. is 'c' i.e., Pathogenicity to rabbits differentiates M. tuberculosis and M. bovis . Culture is a very sensitive diagnostic technique for detection of tubercle bacilli, detecting as few as 10 to 100 bacilli/ml. . At least 10, 000 (109 acid fast bacilli should be present per mil of sputum for them to be readly demonstrable in direct smear. Differentiation between M. tuberculosis and M box is Type Nitrate reduction Niacin Oxygen preference Growth on TCH Pyrozinamide Growth culture . M. Tuberculosis . M. bovis (+)ve (-)ve +ve (-)ve Aerobic Microacrophilic + - Senstive resistant Luxuriant (eugonic) Sparse (dysgonic) . About option 'c' Pathogenecity to Rabbit is used to differentiate M bovis from BCG strain (attenuated strain of M. bovis, not from M. tuberculosis).