Cell-free filtrates of broth cultures from 11 of 18 strains of Pseudomonas aeruginosa isolated from patients with cystic fibrosis (CF) (or from patients without CF) increased substantially the secretion of mucin by explants of trachea from guinea pigs and human tracheal tissue obtained at autopsy. The effect was not related to the mucoid nature of the isolates, was not destroyed by heating at 90 °C for 30 minutes, and was not dependent on serotype. As P aeruginosa commonly infects the respiratory tracts of persons with CF, elaboration of an extracellular product that stimulates mucin secretion could play a role in the pathogenesis of the disease in the airways.
Adler KB, Winn WC, Alberghini TV, Craighead JE. Stimulatory Effect of Pseudomonas aeruginosa on Mucin Secretion by the Respiratory Epithelium. JAMA. 1983;249(12):1615-1617. doi:10.1001/jama.1983.03330360055036