Factors influencing pseudomonas colonization in cystic fibrosis.

In order to assess the relationship between various factors influencing Pseudomonas (Ps) colonization of the respiratory tract of patients with cystic fibrosis (CF) and the appearance of various strains of Ps, two groups of CF patients were studied during a 5-year period. Group A consisted of 24 Ps-negative patients, and Group B consisted of 32 Ps-positive patients, including eight patients who expired. Several clinical and laboratory parameters were evaluated. Although the precise mechanism causing the appearance of Ps in the respiratory tract of CF patients remains elusive, we analyzed several biologic characteristics of both host and organism. This study indicates that frequent use of antibiotics combined with the eradication of Staphylococcus aureus from the respiratory tract heralds the onset of persistent Ps colonization and a subsequent downhill course for CF patients.