Recently, we have established an in vitro human airway cell—dual bacterial biofilm infection model, whereby P. aeruginosa and S. aureus form mixed-species biofilms on monolayers of human bronchial epithelial cells homozygous for the ΔF508 cystic fibrosis transmembrane conductance regulator mutation (CFBE) (10, 34). This evidence concerns the gene CFTR and infection.