Mycobacterium Avium Complex

Mycobacterium Avium Complex

Mycobacterium avium complex (MAC) is a very serious illness caused by Mycobacterium avium, a bacterium commonly found in water, soil, and some animals. MAC rarely develops in patients with a CD4+ count greater than 100 cells per cc and is most common in patients with counts below 50. MAC can be limited to one part of the body or can spread throughout the body (called disseminated MAC, or DMAC). Parts of the body that are most commonly affected include the lungs, lungs, intestines, bone marrow, liver, and spleen.

Symptoms include fever, chills, diarrhea, weight loss, stomach ache, fatigue, and anemia (low number of red blood cells). Although these symptoms are common for many AIDS-related illnesses, if a patient with a CD4 count below 100 experiences fever, anemia, diarrhea, and weight loss, it is assumed that he or she has MAC until proven otherwise. This is especially true for patients who are not on antiretroviral therapy and those who have just started therapy. When MAC spreads through the body, it can cause serious complications such as blood infections, hepatitis, and pneumonia.

Fortunately, MAC is rare in patients who are on antiretroviral therapy. Most newly diagnosed infections occur in patients who are not receiving antiretrovirals or who have recently started therapy.

Since MAC can develop resistance to antibiotics, in the same way that HIV can develop resistance to antiretrovirals, MAC treatment usually involves a combination of antibiotics such as clarithromycin, ethambutol, and rifabutin. These drugs can interact with the medications used to treat HIV, so patients with MAC should be treated by health care providers who have thorough up-to-date knowledge about HIV treatment. Patients with CD4 counts below 75 should talk to their doctors about prophylaxis to prevent MAC.