All the following are true of Tuberculosis except ?
For sputum to be positive, (A194) bacilli should be > 1
Niacin test differentiates M. tuberculosis and M. bovis
Pathogenicity to rabbits differentiates M. tuberculosis and M. bovis
All
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).