Clostridium difficile toxin A (TcdA) is a toxin generated by Clostridium difficile.
C. difficile produces two major kinds of toxins that are very potent and lethal; an enterotoxin (Toxin A, this protein) and a cytotoxin (Toxin B).
The toxins are the main virulence factors produced by the gram positive, anaerobic, Clostridium difficile bacteria. The toxins function by damaging the intestinal mucosa and cause the symptoms of C. difficile infection, including pseudomembranous colitis.
C. difficile is found in nature in water, air, human and animal feces, on most surfaces (especially in hospitals) and most prevalently in soil. It can be transferred from person to person through the fecal-oral route. Most often C. difficile is acquired nosocomially.
Patient symptoms with C. difficile intestinal infections include diarrhea, inflammation, fever and abdominal pain. The inflammation associated with C. difficile infection has been shown to be caused by toxin B’s interaction with mast cells which release inflammatory granules in addition to toxin A causing an increase in expression of prostaglandins.
C. difficile is responsible for almost all cases of antibiotic associated pseudomembranous colitis which involves many of the above mentioned systems.(3) In addition, it has been found that even strains of C. difficile that lack toxin A (A-B+) are still capable of causing pseudomembranous colitis.