Ah, yeast. The bane of CF persons. Antibiotic use allows yeast to overgrow. But sometimes you just have to have antibiotics in CF care.

I would ask for a trial of oral suspension Nystatin first (that she would wish in her mouth and swallow at least once a day). Let your daughter take it for a full 2 months, then try another culture. If she still is culturing it, then you could think about a bronch. But a bronch is invasive and is not without risks--including risks of infection. So I would not be cavalier about that at all!