Interpretation of pharmacologic data in respiratory tract infections

Few serum pharmacokinetic parameters of antibiotics are predictors of tissue distribution and, for instance, more useful are studies of tissue concentrations in the respiratory tree. Significant antibiotic concentrations can be obtained at various sites of potential infection: lung parenchyma; alveolar macrophages; and bronchial mucosa and secretions. New models using broncho-alveolar lavage allow studies of antibiotic concentrations in epithelial lining fluid that are good predictors of antibiotic activity in lung infections. In studies in human respiratory tissues for superinfected bronchitis, concentrations of macrolides, quinolones or beta-lactans in bronchial secretions, or mucosa, correlated with satisfactory clinical response, and eradication of pathogens. Pulmonary kinetics of aminoglycosides or beta-lactams have been studied using a canine model. Also in murine models of pneumonia, pharmacokinetic parameters have been determined for quinolones and newer macrolides.