Hi Beth, I know it seems counterintuitive to NOT treat what seems to be an infection, but here's the logic behind it.
First keep in mind that many causes of discolored mucus can be viral in nature, and do not respond to antibiotics. They simply "run their course " while you are taking the ZPak and things coincidentally return to normal.
People with bronchiectasis and COPD are vulnerable to several slow growing and difficult infectious organisms including various Mycobacteria and Pseudomonas. Neither of these infections can be "knocked out" with a short course of a single antibiotic. In fact, repeated short doses can build resistant organisms in your lungs and elsewhere in your body.
The usual course of treatment for infection is to do a sputum culture to determine the exact infectious organism, followed by sensitivity testing to determine which antibiotics are needed to treat it.
Pseudomonas may respond to one or two courses of a .Chlorquinolone like Levaquin, or may require a course of inhaled (nebulized) antibiotic like Tobramycin.
MAC often requires 18 months or longer of a 3-4 antibiotic regimen, either 3 times weekly or daily. It is very hard on the body, and may not eradicate the infection.
Because of the difficulty of treatment, many pulmonologists discourage early antibiotic use absent clear evidence of infectious pockets.
My MAC was treated for 18 months and didn't go away (it did get better) but my body could no longer tolerate the side effects. We stopped antibiotics, but I continue airway clearance with 7% saline solution and an Aerobika to bring up mucus. During an exacerbation I add a neb of Levalbuterol. I also get exercise daily through fast walking or vigorous play with my grands, for whom I provide daycare. This has kept me healthy for 9 months now.
Has your doc done or suggested a sputum culture? I'll check back later to see if you have any questions.