Can healthy young adults acquire MAC lung infection?

Dear Ask The Doctor: Hello, I am 29 yr old Asian male (thin, weigh 50 kgs, height 110 lbs) who has been recently been diagnosed (presumed) with TB (infitrate in the upperlobe with plueural effussion). I am still waiting on the results from the cultures from my Sputum and Bronchoscopy and biopsy culture from lymp supclaviculr lymphone which had a swelling. One of the suputum cultures turned positive for MAV (Mycobacteriam Avium - Intercellulare. The lymphnode biopsy turned AFB positive but still awaiting the results of the exact bacteria that is growing in the culture. As part of the diagnosis, I have been tested for HIV and the results are negative. I have been a smoker quit 1 year ago and also smoked 1-2 a day for 5-6 yrs) and drink alcohol (1 time a week). I am not sure what would be my situation. Also, I have Tachycardia. I had 2 female sexual partners till now and had sex two times (protected sex only) and that two 2 years back. As mentioned above, the recent HIV test taken 1 month back showed no antibodies for HIV-1, 2 (non-reactive). During the 2 years, i did not had any sexual encounters nor any oral sex nor i use needles for drugs etc. Does a negative HIV test after 2 years of exposure assure a 100% HIV negative result to be relieved of the anxiety. I am asking this questions, because, the MAC in suptum is causing a worry, as healthy males (as young as 29 years) who are not HIV positive donot get affected with MAC. My case is being referred to National Jewish center too. I am really worried. Please, help me what is going on with me. As now I am on the standard TB medication along with the Clarithromycin for the MAC infection treatment.

Dear Raghu: After a possible exposure, it would usually take 3-6 months for both antibodies to be detectable. If you want, you may request another HIV test a year from now, just to be sure.True, MAC lung infection is more common in immuncompromised individuals (depressed immune system) but it can still happen in immunocompetent (intact immune system) individuals. In short, healthy males and females can have it too but it is not very common. I hope this helps.