SummaryThe F71and F71P‐fimbriae ofEscherichia coliare encoded by thefso(F seven one) andfst(F seven two) gene clusters, respectively (Van Dieet al., 1984; 1985).With the immunocytochemical gold‐labelling technique it was demonstrated that both the FsoE and FstE proteins are non‐adhesive minor fimbrial sub‐units located at the tip of the fimbrial structure. The FsoF and FstFG proteins play an important role in the initiation of polymerization of the minor and major subunits into the fimbrial st