Pefloxacin and immunity: cellular uptake, potentiation of macrophage phagocytosis and intracellular bioactivity for Klebsiella pneumoniae.

Antibiotic potentiation of host defence mechanisms may be of potential clinical importance in the outcome of infections. Therefore the effect of pefloxacin upon the interaction of in vitro of human macrophages with Klebsiella pneumoniae, by assays of antibiotic cellular uptake, bacterial phagocytosis and intracellular killing, was examined. The results indicated that pefloxacin was well concentrated by phagocytes at all the concentrations tested. The uptake proceeded rapidly and was not affected either by cell viability or physiological environmental temperature. Synergistic phagocytosis and intracellular killing of K. pneumoniae was observed in the presence of macrophages and subinhibitory concentrations (one-half MIC) of pefloxacin. Pretreatment of bacteria with pefloxacin led to an increase in both bacterial uptake and microbicidal activity of phagocytes. Exposure of the macrophages to pefloxacin did not affect any phagocyte functions.