Interference with granulocyte function by Staphylococcus epidermidis slime

The interaction of Staphylococcus epidermidis slime with human neutrophils (PMN) was examined by using isolated slime and allowing bacteria to elaborate slime and other extracellular products in situ. S. epidermidis slime was found to contain a chemoattractant. Incubation of PMN with 50 μg or more of slime per ml inhibited subsequent chemotaxis of the PMN to n-formyl-methionyl-leucyl-phenylalanine by 27% and to zymosan-activated serum by 44 to 67% with incresing slime concentrations. S. epidermidis slime stimulated little degranulation of untreated PMN. After pretreatment of PMN with 5 μg of cytochalasin b per ml, slime predominantly induced release of specific granule contents (33.8% lactoferrin release by 250 μg of slime per ml versus 10% myeloperoxidase release by 250 μg of slime per ml). By a surface phagocytosis assay, PMN uptake of radiolabeled S. epidermidis which were incubated for 18 h on a plastic surface for slime expression was less than that for S. epidermidis adhered to the plastic for 2 h or grown in unsupplemented nutrient broth. These results suggest that S. epidermidis slime interaction with PMN may be potentially detrimental to host defense and may contribute to the ability of this organism to persist on surfaces of foreign bodies in the vascular or central nervous system.