Biofilm formation and adhesion to cystic fibrosis bronchial epithelial cells increase during long-term colonization of CF patient lungs. Biofilm formation and adhesion to cystic fibrosis bronchial epithelial cells increase during long-term colonization of CF patient lungs. Biofilm formation (A) and adhesion to CFBE41o− cystic fibrosis lung epithelial cells (B) increase for clade C2 and C3 isolates (*, P < 0.05; ***, P < 0.001 by Tukey’s HSD multiple-comparison test). Clade C1 also includes isolate BM1. Inês N. Silva et al. mSystems 2016; doi:10.1128/mSystems.00029-16