The effects of extracellular slime from Staphylococcus epidermidis on phagocytic ingestion and killing

Abstract

Extracellular slime (Ecs) from three strains of Staphylococcus epidermidis was prepared and added to fresh suspensions of polymorphonuclear neutrophils. Phagocytic ingestion and killing of opsonised and unopsonised S. epidermidis strains was assessed over time using slide preparations stained by the Gram's method and microbiological culture. Both phagocytic ingestion and killing were inhibited. Investigation as to one possible mechanism of action of Ecs on phagocytes was performed using 1 mu polystyrene spheres which were incubated overnight with Ecs. It was found that the surface tension was altered with Ecs making the beads more hydrophilic, a factor which may interfere with the phagocytic response to infection.