Gina, Irene and others,

Here is a link that I pulled off of one of these discussion pages when I first went through them all in December.
http://www.thoracic.org/patients/lung-disease-week/2016/nontuberculous-mycobacteria-week/webinar.php
It's a webinar put out by the American Thoracic Society entitled Strategies for Reducing Environmental Exposure to NTM. In there, the doctor states that it can take 1-10 years to have MAC diagnosed so you very rarely know how you got it. I would expect that in 10 years time, I have potted many plants, dug up a bunch of soil, taken tons of showers, been in the hot tub at least once, and on and on. It's a guessing game with no answers typically.

Linda