Antibiotic therapy in cystic fibrosis. Evaluation of efficacy.

Eradication of the bacterial pathogen, resolution of the local and systemic inflammatory signs, and recovery of organ function are the main criteria by which antibiotic treatment is evaluated. In cystic fibrosis (CF) the pathogen is seldom eradicated and systemic markers of inflammation are not always present. The main criterion for assessing the results of antimicrobial therapy in CF is therefore clinical improvement. The use of clinical scoring systems and double-blind design in therapeutic trials can reduce bias in evaluation of outcome. Assessment of the contribution of antibiotic therapy to the outcome requires greater knowledge of the role of bacterial infection in the pathogenesis of pulmonary exacerbations and could be improved by the development of quantifiable markers in respiratory secretions for inflammation.