Which species is known for being nitrate reduction positive and niacin positive?

The species known for being nitrate reduction positive and niacin positive is Mycobacterium tuberculosis. This bacterium is a significant pathogen responsible for tuberculosis and is characterized by its ability to reduce nitrate to nitrite, which is a distinctive biochemical feature. Additionally, it is positive for the production of niacin, which can be detected in laboratory tests and is one of the tests used to differentiate Mycobacterium tuberculosis from other mycobacterial species.

In the context of the other species listed, Mycobacterium bovis does not show consistent niacin production, and while it can be nitrate reduction positive, it is not the characteristic feature that differentiates it from M. tuberculosis. Mycobacterium avium is also known to be nitrate reduction negative, which further confirms the distinguishable features of M. tuberculosis. Mycobacterium kansasii may exhibit different biochemical activities, as it does not consistently demonstrate the same nitrate reduction characteristics as M. tuberculosis.

Thus, the combination of nitrate reduction positivity and niacin positivity distinctly identifies Mycobacterium tuberculosis among the choices provided.