Concentrations of Antibiotics in Bronchiolar Secretions of the Patients with Chronic Respiratory Infections

Abstract

In order to determine the adequate dose in antibiotic treatment for chronic respiratory infections, antibiotic transport into respiratory tract was studied about 27 patients treated with 16 antibiotics, with following results: 1) In all patients in whose expectorated sputum antibiotic concentrations were higher than the MICs for their causative agents, these agents were eliminated. 2) Ratios of sputum peak levels of antibiotics to serum peak levels were 0.1 to 2.0% with penicillins, 1.0 to 3.0% with cephalosporines, 25 to 35% with Thiamphenicol, 16 to 57% with Minocycline and 15 to 25% with aminoclycosides. 3) Antibiotic concentrations in intra-bronchiolar secretions were measured, and followings were revealed; i) Antibiotic concentrations were different in every bronchioles. ii) In the patients whose causative agents disappeared despite the fact that antibiotic concentrations were lower than the MICs for the organisms, higher concentrations were detected in their intra-bronchiolar secretions.