Genetic determinants of Pseudomonas aeruginosa colonization in cystic fibrosis patients in Canada.

The present study was aimed at analyzing whether the rate of colonization and the age at colonization with Pseudomonas aeruginosa was genetically determined in cystic fibrosis (CF) patients. These two variables were calculated among 127 CF patients whose genotypes were known and who were monitored at the Clinique de Fibrose Kystique in Saguenay Lac-Saint-Jean. No statistically significant differences were found in the rate or the age at colonization when the patients were grouped by genotype; however, this result could be due to the small number of patients in each genotype group. The rate of colonization was significantly lower among CF patients carrying the A455E mutation, a "mild" allele with respect to exocrine pancreatic function, than among those carrying either the deltaF508 or the 621 + IG- > T mutation, both of which are "severe" alleles. The results confirm previous reports that the rate of colonization with Pseudomonas aeruginosa is, at least in part, genetically determined.