Because mucus in the lungs can feed bacteria, your pulmonologist would have better answers for you. Usually nebulizing saline and producing sputum helps keep the lungs more inhospitable to the bacteria.

I believe, I may be wrong, that getting moisture directly into the lungs via saline solution, nebulizing is the key to loosening the mucus that is building and sitting there that won't come up. Getting that mucus out will help us to keep ourselves healthy and infections down and hopefully cleared. So, one helps oneself by getting moisture directly into the lungs, (nebulizing) mucus drainage techniques, exercise and huff coughing.
Hope you are getting the answers here on our very special site and with the help others give us.
Barbara

The issue is not the production of sputum - we all have mucus coating the insides of our lungs but some have much less than others. And some have very sticky mucus that is not easy to move or to expel.
The issue is to keep the mucus that is in there thinned and moving - stagnant pools or pockets are breeding grounds for bacteria like MAC/MAI and Pseudomonas.

Hence, even with little mucus, the concept of airway clearance is important. Here is one of the very best video tutorials I have found on the subject: