Clostridioides difficile (previously known as Clostridium difficile) is the cause of antibiotic-associated diarrhea (AAD) and pseudomembranous colitis (PMC). PMC is an inflammatory disease of the colon caused by toxins of C. difficile.
C. difficile produces two potent toxins:
- Toxin A (TcdA), an enterotoxin
- Toxin B (TcdB), a cytotoxin
It is the production of these toxins in the gastrointestinal tract that ultimately leads to disease. There is a relationship between toxin levels, the development of pseudomembranous colitis (PMC), and the duration of diarrhea.
For many years, toxin A was regarded as more important than toxin B in the disease process. Later on, disease-producing strains producing only toxin B were identified. These strains produced serious disease, and toxin B was found to be responsible for more serious damage to intestinal cells.
