Synergy of ceftazidime and human macrophages on phagocytosis and killing of Staphylococcus aureus and Pseudomonas aeruginosa.

The effect of ceftazidime on the phagocytic and bactericidal activity of human macrophages was investigated. At concentrations of half the MIC the antibiotic caused macrophages to ingest and kill Staphylococcus aureus and Pseudomonas aeruginosa at a higher level than did macrophages without drug. Bacteria pretreated with ceftazidime became more sensitive to the bactericidal activity of macrophage lysozyme. Macrophages taken from mice receiving intravenous ceftazidime showed greater phagocytic activity than those from control mice.