Polymerase Chain Reaction Analysis, Detection and Typing of Toxin Producing Clostridium Difficile

Clostridium difficile, the primary cause of pseudomembranous colitis (PMC) in humans, produces two toxins; toxin A, an hemorrhagic enterotoxin and toxin B, a potent cytotoxin. Both toxin proteins appear to act synergistically to induce colitis and PMC. Size estimates of the toxin proteins have varied widely; however recent DNA sequence information estimated the size of toxin A to be 307,972 daltons (Dove et al. 1990 4 and toxin B to be 269,696 daltons (Barroso et al. 1990). These large bio-toxins are only found in pathogenic strains of C. difficile but not found in non-pathogenic strains. In addition to the studies of the toxin proteins, a number of labs have been investigating the molecular biology of these toxin genes.