Comparison of the effect of phenoxymethylpenicillin, cloxacillin, and flucloxacillin on Staphylococcus aureus phagocytosed by human monocytes.

The antibacterial effect of phenoxymethylpenicillin, cloxacillin, and flucloxacillin on pre-opsonized Staphylococcus aureus ingested by human monocytes and on preopsonized S. aureus in suspension was compared. The antibiotics were 1.7-3 times more effective against intracellular S. aureus than against S. aureus in suspension. No influence of acid stability or lipid solubility of the drugs on the antibacterial effect against intracellular S. aureus was demonstrated.