@pkayh not the air...if that were the case it would be TB...water and soil.

@boomerexpert For us to get MAC from soil, isn't it because we inhale the bacteria that get into the air by soil being disturbed, like when gardening? Or is it through touching, such as after gardening you forget to wash your hands? But the latter does not make too much sense to me.

@ling123 unknown although makes the most sense...but what is known is the main distinguishing factor of MAC vs TB is that TB is spread person to person via air thus the reason for the reporting requirement vs MAC contracting via inhaling water vapor and somehow via soil...apparently how one gets it determines how "dangerous" it's considered vs the harm it does...goofy, eh?

I am 99.9% sure it is from ingestion - e.g. inhalation of those bugs. I am the queen of vacuuming and am sure I have sucked in more than my share of “dust.”

It is through ingestion/inhalation - but the crux is that it needs a susceptible host which is where we all come in. TB is not dependent on a “susceptible” host. That is the difference between contagious and not. We all have that commonality.

@ling123 - Mycobacteria avium complex - with avium being the key word - airborne. It's the mist from the shower, misters, water sprinkers, and the dirt in the air. Potting soil is a huge incubator of MAC and I wouldn't be surprised if that was my delivery into my lungs. I love working outside and potting plants. Now I wear a mask to do any kind of yard work or potting that works up the soil. Of course, living in AZ doesn't help from that stand point but it beats Upstate NY. Linda

@pkayh Hi. To the best of my knowledge, mac germs are everywhere, but are more concentrated (higher colony count) in different places. For example, they usually colonize in warm pipes and resevoirs. i.e. your hot water tank, water in the ice-maker tank and old water filters. There is a link on this site 'How to Avoid reinfection.

@ling123, I think that disturbed soil increases your odds of inhaling it because people have been known to get MAC from potting soil. There are billions of MAC in one teaspoon of peat. I also learned that pseudomonas can be caught by just touching plants. Wash hands everybody!

@lindam272 by "susceptible host" do you mean immunocompromised? If so that's no longer the case...folks with healthy immune systems are now being infected...

Right! The immunocompetent have become “susceptible” hosts. I have read about different reasons for being susceptible whether it be body type, chest structure or whatever. I don’t think there is a definitive reason yet. What I have read is that nine times out of ten there is a comorbidity with MAC.