I am also symptomless. I found out I had MAC and BE when I went for a chest xray that I was required to have. That was 3 years ago. Unfortunately, I wasn't with the correct doctors, and didn't do airway clearance, or anything for 3 years. I just recently had another scan to find out that the BE is more widespread, along with the appearance of more widespread MAC. I am now with different doctors and doing airway clearance twice per day. Still - I have no symptoms. Because of this, my doctor does not suggest starting antibiotics yet, but I have to give sputum cultures to see the viral load so they can make a better decision. Not exactly easy since I have no sputum! I have to do another scan in 6 months, and if I can't produce sputum, then I'll need a bronchoscopy. I wish you luck. It sounds like you got it early. Just follow your doctor's advice, and make sure you are with doctors who understand this condition. I don't know if you exercise, but if not, start an exercise program. That's a great form of airway clearance too.