Spore antigens in the classification of some clostridia.

The spore antigens of Clostridium sporogenes, C. histolyticum, C. bifermentans and the butyric group were compared. By spore agglutination and fluorescent-antibody technique (FAT) the 69 strains of C. histolyticum were divided into two types: serum raised against type I (66 strains) reacted with all strains of this species but showed no cross reaction with any of the three types of C. sporogenes; serum raised against type II (three strains) did not react with strains of C. histolyticum type I but showed cross reaction with all the 66 strains of C. sporogenes type I. Thus, by antigenic analysis, spores of C. histolyticum type I were found to possess two components designated E and F; E was a type-specific component whilst F was shared by strains of type II. In addition, strains of C. histolyticum type II possessed a second component, G, which was shared by strains of C. sporogenes type I. There was no cross reaction between the precipitinogens of the spores of the two species. Five strains of C. bifermentans formed a homogeneous group as judged by spore agglutination, FAT and precipitation reactions. There was no cross reaction with any of the other proteolytic species studied. Five butyric strains also formed a homogeneous group. Two antigenic components were therefore assigned to the spore antigens of the two groups: J, for C. bifermentans and K, for the butyric strains.