Chronic endobronchial infection with shape Pseudomonas aeruginosa in patients with cystic fibrosis is associated with more serious disease and reduced survival. Methods for reducing or preventing chronic infection with P. aeruginosa involve rigorous infection control measures and avoidance of cross-infection, which may include segregation of clinics according to microbiological status. The strains of shape P. aeruginosa first isolated from the lungs of cystic fibrosis patients are generally of a non-mucoid phenotype and sensitive to antibiotic therapy. There is some evidence that early aggressive antibiotic treatment may delay chronic infection, improve lung function and improve survival. Further research is needed into the accurate diagnosis of early infection with shape P. aeruginosa, which is often intermittent. In addition, the optimal treatment of patients at first isolation and early colonisation needs to be researched, including choice of antibiotic(s) and route, dosage and duration of antibiotic therapy.