Evidence for two adhesive antigens on the K99 reference strain Escherichia coli B41

Immunoelectrophoresis and haemagglutination studies with a K99 antigen extract from the reference strain Escherichia coli B41 (O101:K99) demonstrated both anionic and cationic mannose-resistant haemagglutinins for horse red blood cells. Neither haemagglutinin was produced by bacteria grown at 18 degrees C. Antibodies to the cationic haemagglutinin were demonstrated in antisera to all the K99-positive E. coli strains in every serogroup examined, but antibodies to the anionic haemagglutinin were only detected in antisera to E. coli strains from the O9 and O101 serogroups. Inhibition of E. coli B41 adhesion to calf brush borders and indirect immunofluorescent staining indicated that the anionic haemagglutinin also exhibited adhesive properties.