In cystic fibrosis patients, bronchial infection with Pseudomonas aeruginosa (PA) is frequent, occurring often early in life. It becomes chronic because of a particular relationship between bacteria and host. Intensive antibiotic treatment often permits a transient eradication. When infection becomes chronic, antibiotics must be prescribed in a way to afford resistance. Efficacy of nebulized antibiotics is now recognized. Problems persist. Because of the difficulty to eradicate PA, new strategies may consist in diminishing the pathogenicity of PA, by inhibiting adhesion and virulence factors' production.