Cefonicid potentiation of human macrophage activity.

This study was undertaken to evaluate the in vitro effects of cefonicid on phagocyte functions such as phagocytosis and intracellular killing of phagocytosed bacteria. At concentrations of half the MIC cefonicid caused human macrophages to ingest and kill Klebsiella pneumoniae at a greater rate than did drug-free macrophages. Bacteria pretreated with subinhibitory concentrations of cefonicid became more susceptible to the phagocytic and bactericidal activity of macrophages than untreated microorganisms. Sub-MIC cefonicid pretreatment of macrophages did not reduce phagocytosis and killing, confirming the inability of beta-lactam antibiotics to cross biological membranes.