Interestingly, CK13 expression is increased in CF airways, mainly in bronchiolar and respiratory epithelium (Sajjan et al. 2000), supporting the idea that cable pili may play an important role in the observed high transmissibility and pathogenicity of strains expressing this surface appendage (Mahenthiralingam et al. 1997; Clode et al. 2000). This evidence concerns the gene KRT13 and cystic fibrosis.