The serological relationship betweenBrucellaspp.,Yersinia enterocoliticaserotype IX andSalmonellaserotypes of Kauffmann-White group N

Abstract

SUMMARYThe serological relationship betweenBrucellaspp.,Yersinia enterocoliticaIX, and the group N salmonella serotypesS. godesberg, S. landau, S. morehead, S. neusdorf, S. soerengaandS. urbanawas examined using agglutination, antiglobulin, complement fixation, immunodiffusion and fluorescent antibody methods.Antisera to the group N salmonella serotypes all reacted to significant titres in agglutination and complement fixation, but not antiglobulin or immunodiffusion tests with smooth brucella antigens. These antisera also reacted in agglutination, but not antiglobulin, tests withY. enterocoliticaIX. They did not react significantly in any tests with rough brucella antigens.Conversely, antisera to smoothBrucellaspp. agglutinated group N salmonellas to low titre andY. enterocoliticaIX to titres similar to those given against the homologous strain. Antiserum toY. enterocoliticaIX on the other hand reacted with smooth brucella antigens to high titre in agglutination, complement fixation and antiglobulin tests, and with the group N salmonella antigens to substantial titres in agglutination tests.In direct fluorescent antibody tests, smoothBrucellastrains andY. enterocoliticaIX reacted strongly with FITC-labelled antibody toBr. abortuswhereas the group N salmonella strains reacted weakly.In tests with monospecific antisera to the A and M determinants ofBr. abortusandBr. melitensisrespectively,Y. enterocoliticaIX reacted only with the antiserum to the A determinant whereas group N salmonellas reacted to low titre with both A and M antisera.The results of cross-absorption tests confirmed this relationship and suggested that the O30 antigens of group N salmonella serotypes contained antigenic determinants similar to, but not identical with, the antigenic structure shared by smoothBrucellaspp. andY. enterocoliticaIX.