Mucoidy, defined by constitutive alginate or other extracellular polysaccharide production, is associated with CF P. aeruginosa strains and not often seen in other disease contexts (48, –, 50); therefore, these data suggest that mucoid may arise secondary to chronic lung infection, independent of cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction. Here, CFTR is linked to cystic fibrosis.