Role Played by Serum, a Biological Cue, in the Adherence of Enterococcus faecalis to Extracellular Matrix Proteins, Collagen, Fibrinogen, and Fibronectin

Background. Most previous studies have found that Enterococcus faecalis isolates do not show significant adherence to fibronectin and fibrinogen. Methods. The influence of various conditions on E. faecalis adherence to extracellular matrix (ECM) proteins was evaluated using a radiolabeled-cell adherence assay. Results. Among the conditions studied, growth in 40% horse serum (a biological cue with potential clinical relevance) elicited adherence of all 46 E. faecalis strains tested to fibronectin and fibrinogen but not to elastin; adherence levels were independent of strain source, and adherence was eliminated by treating cells with trypsin. As previously reported, serum also elicited adherence to collagen. Although prolonged exposure to serum during growth was needed for enhancement of adherence to fibrinogen, brief exposure (