Which Mycobacterium species is associated with livestock and is a zoonosis?

• A. M. bovis
• B. M. fortuitum
• C. M. gordonae
• D. M. xenopi

Answer: (A)

M. bovis is the species tied to livestock and recognized as a zoonosis. It causes bovine tuberculosis in cattle and can be transmitted to humans through contact with infected animals or ingestion of unpasteurized dairy products. This organism is part of the Mycobacterium tuberculosis complex and shares many features with M. tuberculosis, but it has particular clinical and laboratory characteristics, including typical resistance to pyrazinamide, which helps differentiate it in testing. The other listed species are environmental slow- or rapid-growing mycobacteria (M. fortuitum, M. gordonae, M. xenopi) that are not primarily associated with livestock or zoonotic transmission.