W. Calame et al., Contribution of alveolar phagocytes to antibiotic efficacy in an experimental lung infection with Streptococcus pneumoniae, J INFECTION, 42(4), 2001, pp. 235-242
Objectives: The effect of cyclophosphamide-induced leukocytopenia on the ce
llular defence and on the efficacy of penicillin treatment in a Streptococc
us pneumoniae pneumonia model in mice was studied.
Methods: The number of alveolar phagocytes was determined in broncho-alveol
ar lavage (BAL) fluid as well as the number of bacteria in both BAL fluid a
nd homogenized lung tissue.
Results: Eighteen and 21 h after infection, leukocytopenic animals had sign
ificantly lower numbers of alveolar phagocytes than controls, while the num
bers of bacteria in both BAL fluid and lungs were significantly higher. The
number of bacteria was inversely related to the dose of penicillin and the
number of alveolar macrophages. The number of alveolar granulocytes was in
versely related to the dose of penicillin.
Conclusions: Leukocytopenia due to cyclophosphamide impairs the cellular de
fence in the lung against Streptococcus pneumoniae and the dose of penicill
in must be increased to compensate for the higher outgrowth of bacteria in
these leukocytopenic mice, compared to normal animals. (C) 2001 The British
Infection Society.