@jkiemen I think that like @123ling said, these mycobacteriums are everywhere in the environment, and they probably are found in the throat and nose. I don't know if they can 'colonize' there or not. I would think they could in the sinuses as mold can. The lungs seem to be a favorite place due to the amount of plegm that collects there. They thrive in a moist and warm environment. In rare instances, MAC can disseminate into the rest of the body. In India, they commonly practice Ayervedic regimens. One example is clearing the nose and sinuses with a netti pot every day. I did that recently when I felt a cold coming on and it never got me.