Penetration of cephradine into normal, inflammatory, and infected pleural fluids in rabbits

Abstract

Little information is available about antibiotic concentrations achieved in pleural fluid with different underlying conditions of the pleura in animals or humans. Therefore, we studied in a rabbit model the penetration of cephradine into normal pleural fluid, sterile inflammatory pleural effusions, and empyemas induced by Streptococcus pneumoniae. Cephradine was shown to penetrate well into pleural fluid under all conditions. Almost all pleural fluid concentrations were at least 60 % of the simultaneous serum concentrations. Pleural fluid concentrations usually exceeded the MIC of bacteria for which cephradine might be used clinically. There was a trend for an increased pleural-fluid-to-serum ratio of cephradine in the presence of infection. We conclude that cephradine penetrates well into rabbit pleural fluid, regardless of the condition of the pleura. The model described could be used to study the penetration of other antimicrobials into the pleural space.