Let me mention posts from two different MAC members .. hope it helps! Hugs to all! Katherine

Member @pamelasc1, Pamela, and @jentaylor My cough got much worse and I was coughing up stuff I could not believe - my doctor had the sputum tested for pseudemonis, and that is what I had, above and beyond the MAC - has to be treated with Levofloxacin. Once I got on that, it cleared up within 3 weeks and no more coughing up terrible stuff - you may want to get a test for pseudemonis, just to rule it out. The sputum had a distinct taste, smell & color (dark gray & dark green) or color was off white, gray maybe a bit greenish, but mostly grey - and very thick and mucousy.
http://www.medicinenet.com/script/main/art.asp?articlekey=20161