CONDITIONAL ADHERENCE OF ENTEROCOCCUS-FAECALIS TO EXTRACELLULAR-MATRIX PROTEINS

The adherence of 44 clinical isolates of Enterococcus faecalis, a comm on cause of endocarditis, and 13 Enterococcus faecium to substrates of six extracellular matrix (ECM) proteins was examined using S-35-label ed bacteria. One E. faecalis strain, isolated from a patient with endo carditis, adhered to collagen types I and IV and another E. faecalis s train adhered to laminin and to collagen types I and IV. However, most isolates showed little adherence (< 5% of added cells adhered) when g rown at 37 degrees C regardless of their source (endocarditis, urine o r fecal sample). When grown at 46 degrees C (but not when grown in CO2 or nutrient limited media), most isolates of E. faecalis increased th eir adherence to immobilized laminin, collagen types I and IV but not to fibronectin, fibrinogen or bovine serum albumin, whereas none of th e E. faecium increased adherence when grown at 46 degrees C or 50 degr ees C, The adherence of E. faecalis was eliminated by digestion with t rypsin, suggesting that a protein is somehow important, directly or in directly, for adherence to occur. Pre-incubation of bacteria with solu ble collagen types I and IV inhibited the adherence to these ECM prote ins. These results demonstrate that in E. faecalis, adherence to ECM p roteins is produced during routine in vitro growth conditions by occas ional isolates and can be produced during certain stressful growth con ditions by others. Whether this adherence relates to the propensity of E. faecalis to cause endocarditis remains to be determined. (C) 1998 Published by Elsevier Science B.V. All rights reserved.