You may be right. However, I was thought to have it for 7-8 months. The experienced local pulmonologist, who does a lot of critical care work, told me my CT’s looked terrible. They showed trees-in-bud, ground glass, mass like atelectasis in linga and scarring. (Mayo said they see worse.) I developed bronchiectasis between the CT’s when I hadn’t been told about airway clearance or given adequate treatment for sinuses. The negative cultures were a surprise.

I’m writing this not just for you, but for future readers with a tentative diagnosis who search old threads. It’s best to have the real facts (cultures) and a treatment plan. I had to go to Mayo for mine.
Again, I wish you great luck, and great providers and support systems. This forum has been extremely helpful to me.

10 years ago at age 57 I had a CT that had all the features of MAC, according to pulmonologist and radiologist. Had bronchoscopy, nothing grew on culture. This process was repeated several times over the past 10 years, with progression of the Bronchiectasis, nodules etc, but cultures all negative. Until last spring, when bronchoscopy yielded positive MAC culture.
I started azithromycin, Ethambutol and Rifampin 3x/week. Rifampin gave me fevers of 103, flu-like symptoms. Tried Rifabutin, same side effects. So I took just the remaining two drugs. Had a bronchoscopy in December to get a current culture, so insurance could consider the addition of (inhaled) Arikayce. After 8 weeks- no bacterial growth! My pulmonologist and infectious disease doctor were pleasantly surprised. Of course I will have to continue the azithromycin and ethambutol until December (one year after negative culture). And I’m sure it will have to be cultured again at that time.
Just wanted to let you know that there can be successful outcomes. Since our Bronchiectasis still remains, we have to adjust to living with a chronic condition, do lots of research, and be our own health advocates. Best of luck to you.