Mycobacterium kansasii is a type of bacterial infection that can cause life-threatening symptoms in people who have compromised immune systems. People who have healthy immune systems may also be infected with M. kansasii. However, the symptoms they experience are not usually life threatening and are often limited to lung problems. In people with advanced HIV disease, M. Kansasii usually involves the lungs and can spread to other organs, including the liver, the spleen, and the bone marrow.
M. kansasii can be found virtually anywhere in the environment. They live in water, soil, foods, and a variety of animals. HIV-positive people with compromised immune systems living in midwestern and southwestern parts of the United States are at a higher risk of developing disease caused by M. kansasii.
Fortunately, the same drugs used to prevent Mycobacterium avium complex (MAC) – which should be started by all HIV-positive people with T-cells below 75 – may also help prevent M. kansasii infection from causing disease. In other words, an HIV-positive person who is taking medications to prevent MAC may also be protected against M. kansasii.