[Antibiotic therapy in cystic fibrosis. II Antibiotic strategy].

Antibiotherapy is one of the main treatments of cystic fibrosis, contributing to a better nutritional and respiratory status and a prolonged survival. The choice of antibiotics depends on quantitative and qualitative analysis of sputum, bacteria resistance phenotypes and severity of infection. Haemophilus influenzae infection can be treated orally with the association of amoxicillin-clavulanic acid or a cephalosporin. Staphylococcus aureus generally remains sensitive to usual antibiotics; in case of a methicillin-resistant strain, an oral bitherapy or a parenteral cure can be proposed. Treatment of Pseudomonas aeruginosa is different in case of first colonization or chronic infection: in first colonization, parenteral antibiotherapy (beta-lactams-aminoglycosids) followed by inhaled antibiotherapy may eradicate the bacteria; in chronic infections, exacerbations require parenteral bi-antibiotherapy (beta-lactams or quinolons and aminoglycosids) for 15 to 21 days, inhaled antibiotics between the cures being useful to decrease the number of exacerbation. A careful monitoring of antibiotherapy is necessary because of possible induction of bacterial resistance, nephrotoxicity and ototoxicity of aminosids and allergy to beta-lactams.