CFTR and cystic fibrosis: Although P. aeruginosa reduced VX-809 stimulated F508del-CFTR Cl secretion in CFBE cells and in CF-HBE cells in primary culture, neither Staphylococcus newman nor Streptococcus salavari had any effect on VX-809 stimulated F508del-CFTR Cl secretion in CFBE cells (Fig 4, S4 Table).