Immunological analysis of the EDTA-soluble antigens of Clostridium difficile and related species

Antigens were extracted with EDTA from 32 strains representing 10 species of Clostridium. When these antigens were examined by an enzyme-linked immunosorbent assay, marked cross-reactions were observed between C. difficile, C. sordellii and C. bifermentans. The cross-reactive antigen, visualized by crossed immunoelectrophoresis, was carbohydrate.