Abstract

Escherichia coli strains isolated from patients with colonic disorders (n = 27) and strains isolated from the rectal mucosa of healthy subjects (n = 24) were compared with respect to expression of cell surface hydrophobicity, carriage of intestinal virulence factors, adhesion to tissue culture cells, and expression of binding of extracellular matrix proteins and plasma proteins. Strains isolated from patients with colonic disease did not express a more hydrophobic cell surface than strains from healthy subjects. Few strains from both groups carried genes encoding for recognised virulence factors of E coli. Only one strain, carrying the eae gene induced actin polymerisation in tissue culture cells. Strains from patients with colonic diseases adhered to HT29 cells, which are of intestinal origin, to a higher extent than E coli from healthy subjects. Significantly more strains from patients with colonic disorders than E coli from healthy subjects expressed binding of fibronectin, collagens, laminin, vitronectin, plasminogen, throbospondin, and fibrinogen. Expression of binding of these proteins may influence the pathogenesis of colonic disease by mediating binding to ulcerated tissue, preventing complement induced lysis of bacteria and by exerting proteolytic activity. There was no correlation between serotype, expression of cell surface hydrophobicity, and binding of extracellular matrix and plasma proteins.