@mariierod123 Hi. As my doctor explained it to me: he is treating the bronchiectasis, NOT the mac. I am not, nor was I ever, on the big 3 antibiotics which can have adverse side effects. I have been on monthly antibiotics since 2013, and probably will be for life; without any side-effects. My Mayo dr said he has only seen a person 'cured' of mac after being on antibiotics for ten years, and even at that, only 30% of patients see that cure. I won't be one of them because my lung are far too damaged at this point from several lung diseases. Bronchiectasis is a structural lung disease. That is non-reversible, and the damaged lung tissue is susceptible to mac, pseudomonas, and many other bugs that can infect the lungs. That is the purpose of on-going prophalaxis (preventative) antibiotic use. The mac is difficult to get rid of because it has a protective membrane that doesn't allow the antibiotics to reach it's core. The antibiotics do however, thwarts it's reproduction. In other words, it keeps it from totally colonizing your lungs.