CFTR and cystic fibrosis: Cystic fibrosis is characterized by a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR), a membrane-based chloride channel, which initially causes dehydration of the airway surface liquid thereby increasing susceptibility to bacterial and fungal infections (e.g., Pseudomonas, Staphylococcus, Burkholderia, atypical mycobacterium) (33).