Hi D,
I cannot help with questions for infectious disease dr but I've been told nebulizing with 7% saline has been shown to inhibit the growth of MAC bacteria by providing an environment this bacteria do not like. I've have bronchiectasis and MAC for several years now. I am not on any antibiotics due to my fear of the side effects. My daily routine is to nebulize with 7% hypertonic saline, along with using the Aerobika device followed by 20 minutes with the compression vest. Prior to using the saline, I had a very bad cough and a lot of congestion. But, since I started the saline nebbing, my cough and overall condition has improved greatly. I know figuring out all of this is so hard. Best of luck to you.