CFTR and cystic fibrosis: The results clearly showed the high persistence of the P. aeruginosa CF isolates PAET1, PAET2, and PAET4 inside the bronchial 16HBE14o- and CF-affected CFBE41o- cells, with intracellular CFUs maintained at ~1x107 CFUs/monolayer over the course of the experiment (Figure 2).