Clostridium difficile is the causative agent of antibiotic-associated diarrhea and pseudomembranous colitis. It
produces two major exotoxins (Toxin A and Toxin B), which are the prototypes of the family of large clostridial
cytotoxins. Some strains of C. difficile also produce a binary ADP-ribosylating toxin (CDT) which modifies actin. The
pathogenic role of CDT Binary Toxin in diseases induced by C. difficile is not clear, but about 10% of strains isolated
from patients with colitis contain CDT Binary Toxin genes。