Hi Melissa,
I will PM you, but I want to answer this for anyone else who might have questions about sputum color as how it relates to infection. Keep in mind I am not a doctor and I'm just trying to explain things as best as I understand them as how this has related to my case.
In my case, I have never had clear sputum (since onset of symptoms at 21). So if your sputum is usually clear, I would assume you are way ahead of the game (at least ahead of me). According to my doctor, it is erroneous to assume that green is always infection. In my case, because the sputum sits inside the lungs and cannot come out easily, it "cooks" and turns green. In other words, green sputum can mean old sputum. But if I am going through an exacerbation, the doctor will ask me if my sputum has increased, in amount and thickness, and has the color changed to a darker color. Again, just one part of the equation in determining infection or inflamation.
When I was at the doctor last week, we were talking about yellow sputum (stange conversations, I know). She said yellow also can be inflamation/asthma related but doctors don't usually look at that way. So when her patients have yellow, she doesn't assume infection. I'm not sure this info can help anybody because their doctors should be the ones who decide whether someone has an infection or not. My hope is that medical professionals will also be reading this site might start looking at things in new ways and --everybody who has lung disease (not just CF) will have doctors who start considering inflamation as the source of infection and not automatically assume it's always infection.
The other question that you raised about taking antibiotics when your culture is clear. I mentioned to my doctor that I read somewhere that people with bronchitis are over treated with antibiotics. That people who are given antibiotics for bronchitis would get better without antibiotics. People think the antibiotics are making them better. She agreed. She said new guidelines for doctors suggest not giving antibiotics until 10 days after onset of symptoms. So maybe when you had a clear culture (pure conjecture here) and took antibiotics and got better it was bronchitis due to a virus (antibiotics have no affect) inflamation, or from chemical exposures.
When does the doctor prescribe antibiotics? There are so many factors. I don't know if I can simplify it, because she makes the decision. She looks at exposure (smoke, chemicals, pollution). For me, it's always a day or two before. Are my nose, eardrums swollen, red? Throat red? Lungs are probably looking this way too. Peak flow. Chest sounds. Crackles often chemical exposures for me. Fever can be inflamation too. So if she believes it's inflamation, I have to take protective measures and hit more treatments. Sometimes if the asthma is bad, I get a cortisone shot (not often). Inflamation can turn to infection, so if symptoms keep increasing, then I would start Tobi and sometimes Tequin which is now off the market. She also might look at the culture to see if the numbers have increased, but this is also tricky since in the past I have cultured pseudomonas 4+ without any symptoms at all (bugs colonize and are not causing infection).
My doctor uses antibiotics judiciously. But the reason she can prescribe them less is because she says that controlling the asthma component is most important. Proper meds, diet, environment, strict compliance, etc. If you don't control these things, you will end up on antibiotics, because with swollen airways, the mucus cannot get out, and will cause infection. My doctor drop patients who are not compliant because everything she does would be pointless. No quick fixes.
To dsarver: I think your idea of yeast infection sounds so right. Why didn't the doctor consider this?!
Sometimes, I am feeling better from starting abs for a lower lobe infection and I get a viral bronchitis right in the midst of going clear. I stay clear, but feel like crap and cough and cough. I know that I am lucky to have clear sputum when I am not having an exacerbation. Last spring, I thought I had become a perma-green person (I did a poll on the bronchiectasis forum and it was about 50/50 to be green when feeling good). Back in May, I got sick, took abs and got a little better. My sputum was still green, but I had no real fever and felt decent with one or two Advil a day. I didn't like that I was losing ground though and pushed for different abs. I was told by a covering pulmo in my practice that I had a virus and to wait. I went to my PCP and got an x-ray that showed pneumonia in my lower left lobe (to be honest, an x-ray would probably show pneumonia on me no matter how I felt). Sputum culture, more abs that were sensitive to what was growing, but still not better. Finally, I asked for my standby, Avelox, even though I hate the joint pain. I was clear-sputumed in 48 hrs, for the first time two months! So anyway this stuff is a mystery to me.