Pili of Vibrio cholerae non-O1

Pili of Vibrio cholerae non-O1 strain S7 were purified and characterized. The pili of S7 were morphologically, electrophoretically, and immunologically (as far as polyclonal antibody was used) indistinguishable from the 16-kilodalton pili of V. cholerae O1 strain 82P7. The purified pili and organisms had D-mannose- and L-fucose-resistant hemagglutinin. The hemagglutinating activity of the purified pili was inhibited by the Fab fraction of antipilus antibody, but the hemagglutinating activity of live organisms was not inhibited completely. The purified pili or Fab fraction of antipilus antibody did not inhibit the adhesion of V. cholerae non-O1 to rabbit intestines. Therefore, the pili were not regarded as a colonization factor of V. cholerae non-O1. A total of 148 V. cholerae non-O1 and O1 clinical isolates were screened for the presence of S7 pili by using an agglutination test with anti-S7 pilus serum; 12 of 49 V. cholerae non-O1 strains and 25 of 99 V. cholerae O1 strains were positive for agglutination. These agglutination reactions were not correlated with adhesion of the organisms to intestines.