A new colonization factor antigen (CFA/III) produced by enteropathogenic Escherichia coli O128:B12

Fourteen enteropathogenic Escherichia coli strains isolated in the Dakar area (Senegal) from cases of diarrhoea in children were tested for the presence of adhesive factors. None of these strains possessed colonization factor antigens CFA/I or CFA/II, but one strain (strain 1373) presented a haemagglutination (HA) type similar to that of the CFA/I reference strain and failed to be agglutinated with CFA/I antiserum. Strain 1373 adhered strongly in vitro to human enterocyte brush borders. HA was not inhibited by D-mannose (which inhibits HA of type 1 pili) or by N-acetylneuraminic acid (which inhibits HA of CFA/I and CFA/II). HA and the adhesion of strain 1373 were inhibited by anti-CFA/III serum but not by anti-CFA/I or anti-CFA/II sera. The colonization factor antigen (CFA) of strain 1373 is a new antigen (which we propose to call CFA/III) and is distinct from CFA/I, CFA/II and type 1 pili. CFA/III has a protein subunit of molecular weight of about 16,000.