Which toxins are produced by Clostridioides difficile?

• A. Enterotoxin A and cytotoxin B
• B. Toxin A and toxin C
• C. Shiga toxin
• D. Diphtheria toxin

Answer: (A)

Clostridioides difficile causes disease mainly through two toxins, known as toxin A (enterotoxin) and toxin B (cytotoxin). These toxins disrupt the intestinal lining by inactivating Rho family GTPases, which dismantles the actin cytoskeleton, breaks down tight junctions, and leads to cell death and a strong inflammatory response. Toxin A mainly drives secretory diarrhea and mucosal inflammation, while toxin B is highly cytotoxic and crucial for the tissue damage seen in pseudomembranous colitis. Some strains can produce additional toxins, but the classic and most important toxins are A and B. Toxin(s) listed from other organisms—such as Shiga toxin from Shigella or certain E. coli, and diphtheria toxin from Corynebacterium diphtheriae—are not produced by C. difficile.