Efficacy of antimicrobial therapy in experimental rat pneumonia: antibiotic treatment schedules in rats with impaired phagocytosis.

Pneumococcal pneumonia in rats with intact host defense mechanisms could be successfully cured by penicillin. The efficacy of this antibiotic therapy was lost in cobra venom factor-treated rats which had selectively impaired phagocytic functions. In these animals the effect of penicillin therapy was improved by increasing the daily dose and the frequency of injections and by earlier initiation of the therapy. The efficacy of penicillin in the cobra venom facttor-treated rats was restored either by markedly increasing the daily dose of penicillin or by increasing the daily dose in combination with a reduced interval of the penicillin injections.