The effect of eight antibacterial agents on the phagocytosis of 32P-labelled Escherichia coli by rat polymorphonuclear cells.

Using 32P-labelled Escherichia coli, the effect of 8 antibacterial agents on the ability of rat polymorphonuclear cells to ingest the labelled bacteria was studied with and without serum present during the ingestion phase. No impairment of ingestion was observed when testing gentamicin, cephalothin and trimethoprim. High doses of oxytetracycline, doxycycline, colistin, erythromycin and chloramphenicol seemed to impair ingestion. The effect was most pronounced when applying 100 mug/ml of doxycycline: the ingestive capability was reduced to 25% without serum and 24% with serum present compared to untreated controls. 83 mug/ml of colistin reduced theingestion to 39% without serum present, this effect being totally eliminated when serum was present during the ingestion phase.