I was diagnosed at 3 months old with CF and in 2001 I grew out Pseudomonas for the first time. I've been on Tobi since on 1 month off 1 month since then. My Dr told me that it would never completely leave me. Once it's there, it is there for good but can be greatly suppressed with the Tobi so that it doesn't even grow when they do a sputum culture. If I don't take my tobi religiously, I develop a bad, productive cough. after just two doses of Tobi my cough is usually gone. I would highly recommend consulting your doctor and asking him to take a culture to see if it grows.