Mycobacterium Avium Complex (MAC) Infection

What is mycobacterium avium complex infection?

Mycobacterium avium complex (MAC) is an infection that is caused by two different bacterias: Mycobacterium avium and Mycobacterium intracellulare. The majority of people do not fall ill from these bacteria; however, those with a weakened immune system, those with a lung disease, and elderly females are at risk. 

There are three forms of MAC infections: pulmonary, disseminated, and lymphadenitis. The first affects the lungs, the second spreads throughout the body, and the third causes swelling of the lymph nodes. 

What are the symptoms of mycobacterium avium complex infection?

Different forms of infection cause different symptoms. Some of the common ones include weight loss, night sweats, fever, and fatigue. If one has a pulmonary infection, they will have these symptoms along with a cough.

If one has disseminated MAC infection, they will experience the common symptoms and diarrhea, shortness of breath, anemia, and abdominal pain. MAC associated lymphadenitis sees the common symptoms and swollen lymph nodes in the neck. 

What causes mycobacterium avium complex infection?

The two forms of bacteria that cause this infection are often found in the water, household dust, and soil. The bacteria enters the body when it is either inhaled or swallowed, but it is not thought to be contagious from one person to another. 

How is mycobacterium avium complex infection diagnosed?

Doctors will look for the characteristic symptoms and perform a physical exam before using tests. Tests include CT scans, X-rays, mucus cultures, and special staining tests. A diagnosis often comes after other infections are ruled out. If necessary, doctors may also take stool, spit, urine, liver, or bone marrow samples. 

What are the treatments for mycobacterium avium complex infection?

Pulmonary and disseminated MAC infections are treated with antibiotics. For the pulmonary form, surgery may be needed to remove a spot that is infected. In terms of the lymphadenitis form, removal of the lymph nodes and antibiotics is used. 

Where can I find out more about mycobacterium avium complex infection?

• • • NIH
    • American Lung Association
    • Everyday Health