Sorry to hear all that you are going through right now. It can definitely seem quite daunting, particularly when dealing with multiple diagnoses at once. I am glad that you are feeling more secure after meeting with the pulmonologist. The changing terminology for these infections and differences across doctors in the use of terms can add to the challenge of finding information about this condition. MAI (mycobacterium avium-intracellulare) is actually an older term for MAC (mycobacterium avium complex). They are both umbrella terms for a group of mycobacteria, of which mycobacterium avium and mycobacterum intracellulare are the species most frequently isolated in humans. It is my understanding that they were the first to be identified and difficult to differentiate, and thus the term MAI was born. With scientific advances, there are now several more species identified and grouped together, so they changed the name from MAI to MAC. There aren't a lot of studies that separate out the different species comprising MAI/MAC, although there are a few. I find that different doctors prefer one or the other term so both MAI and MAC are used across my medical records depending on the physician.