The effect of some antibiotics on phagocytic activity in vitro

Summary To understand the effect of some antibiotics on phagocytic activity, we analysed the influence of different antibiotics on the ingestion phase of human macrophages in vitro . Monolayer cultures were treated with the following drugs: penicillin G, ampicillin, methicillin, cefazolin, cephalothin, tetracycline, doxycycline, streptomycin, gentamicin and tobramycin. The phagocytic activity was assayed by the direct microscopic count of ingested zymosan particles. Penicillin G, gentamicin, tobramycin, doxycycline and tetracycline increased the phagocytic activity of human macrophages in vitro . On the other hand methicillin, ampicillin, cefazolin, and cephalothin appeared to exert an inhibitory effect on phagocytosis.