Which organism is associated with livestock and causes a zoonosis?

Which organism is associated with livestock and causes a zoonosis?

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

Answer: (D)

The key idea is that some mycobacteria have livestock as their source and can pass to humans, making them zoonotic. Mycobacterium bovis is the classic agent of bovine tuberculosis in cattle, and humans can acquire infection through contact with infected animals or consumption of unpasteurized dairy products. This livestock connection is what makes it the correct choice. The other organisms are typically environmental or opportunistic pathogens and not tied to livestock as reservoirs. Mycobacterium gordonae is often considered nonpathogenic and found in water; Mycobacterium xenopi is associated with hot water systems and pulmonary disease; Mycobacterium fortuitum is a rapid-growing species that causes skin/soft tissue and occasional implant infections.

The key idea is that some mycobacteria have livestock as their source and can pass to humans, making them zoonotic. Mycobacterium bovis is the classic agent of bovine tuberculosis in cattle, and humans can acquire infection through contact with infected animals or consumption of unpasteurized dairy products. This livestock connection is what makes it the correct choice.

The other organisms are typically environmental or opportunistic pathogens and not tied to livestock as reservoirs. Mycobacterium gordonae is often considered nonpathogenic and found in water; Mycobacterium xenopi is associated with hot water systems and pulmonary disease; Mycobacterium fortuitum is a rapid-growing species that causes skin/soft tissue and occasional implant infections.