This is a multicenter, prospective, two cohort, observational study over a 5-year period in Cystic Fibrosis (CF) patients with chronic Pseudomonas aeruginosa infection.The study will collect data over 1 year on respiratory function, antibacterial effectiveness, and clinical outcomes of treatment with inhaled antipseudomonal antibiotics and data over 5 years on microbiological and safety assessments.