Concentration of tobramycin given by aerosol in the fluid obtained by bronchoalveolar lavage.

Whereas previous studies have used only bronchial secretions and sputum, in the present study, bronchoalveolar (BAL) fluid was analysed for tobramycin levels after aerosolization of this antibiotic. In 20 adult patients with a variety of lung disorders, the concentration of tobramycin obtained in the first aliquot of the bronchoalveolar fluid varied from less than 0.1 to 9.2 micrograms ml-1 (mean 2 +/- 2.26 micrograms ml-1) with 18 samples above 0.4 micrograms ml-1. In most of the cases, the concentration of tobramycin achieved values of tobramycin in excess of the minimal inhibitory concentration for most of the microorganisms. Thus, sampling fluids by the bronchoalveolar technique offers a suitable method to study antibiotic levels at the site of broncho-pulmonary infection. These results may help explain why aerosol antibiotic treatment appears to be useful in selected patients, especially in cystic fibrosis patients chronically infected with Pseudomonas aeruginosa.