Prevention of severe lower respiratory infections in patients with cystic fibrosis.

Infection of the lower respiratory tract is the most frequent cause of death in patients with cystic fibrosis (CF). Pseudomonas aeruginosa is the predominant pulmonary pathogen; it establishes a chronic endobronchial infection and once acquired is rarely if ever eradicated. Although optimizing nutrition and pulmonary toilet improves the general health of patients with CF, bacterial respiratory infections are neither prevented nor cured. Likewise, attempts to prevent colonization and infection by means of antimicrobial prophylaxis have been generally unsuccessful. Since no effective radical cure for CF pulmonary infections has been found yet, means of preventing respiratory tract colonization have been sought. Immunization of patients who are already colonized with P aeruginosa has failed to eradicate colonization. Vaccines are therefore being sought that will forestall colonization by P aeruginosa, either by preventing adhesion to respiratory mucosa or by enhancing other immunological host defenses.