This agent causes an infection in birds and opportunistically infects people with AIDS.

This agent causes an infection in birds and opportunistically infects people with AIDS.

• A. Escherichia coli
• B. Mycobacterium avium
• C. Candida albicans
• D. Listeria monocytogenes

Answer: (B)

Mycobacterium avium is a non-tuberculous mycobacterium that is commonly found in birds and in the environment. In people with AIDS, especially when CD4 counts fall below about 50 cells per microliter, it can cause a disseminated infection that affects multiple organs such as the liver, spleen, bone marrow, and lymph nodes. This makes it a classic opportunistic pathogen in advanced HIV disease, presenting with fever, night sweats, weight loss, and hepatosplenomegaly. The link to birds and the tendency to disseminate in severely immunocompromised hosts are what make this organism the best fit for the description. The other organisms listed don’t share both the bird association and the prominent risk of disseminated disease in AIDS in the same way.

Mycobacterium avium is a non-tuberculous mycobacterium that is commonly found in birds and in the environment. In people with AIDS, especially when CD4 counts fall below about 50 cells per microliter, it can cause a disseminated infection that affects multiple organs such as the liver, spleen, bone marrow, and lymph nodes. This makes it a classic opportunistic pathogen in advanced HIV disease, presenting with fever, night sweats, weight loss, and hepatosplenomegaly. The link to birds and the tendency to disseminate in severely immunocompromised hosts are what make this organism the best fit for the description. The other organisms listed don’t share both the bird association and the prominent risk of disseminated disease in AIDS in the same way.