What are the two major toxins produced by Clostridioides difficile and their role in disease?

What are the two major toxins produced by Clostridioides difficile and their role in disease?

• A. Enterotoxin alone causing secretory diarrhea
• B. Toxins A (enterotoxin) and B (cytotoxin) causing disruption of cytoskeleton and pseudomembranous colitis
• C. Alpha and beta toxins causing gas gangrene
• D. Tetanus and botulinum toxins causing neuroparalysis

Answer: (B)

The main point is that Clostridioides difficile makes two toxins that drive disease: toxins A and B. These are glucosyltransferases that inactivate Rho family GTPases in intestinal epithelial cells, causing collapse of the actin cytoskeleton. This leads to loss of cell junctions, cell damage, and mucosal injury. Toxin A acts as an enterotoxin, promoting inflammation and secretory diarrhea, while toxin B is a potent cytotoxin that causes extensive cytopathic damage to the lining. The combined effect results in the characteristic pseudomembranous colitis seen in C. difficile infections. Other choices reference toxins from different organisms or unrelated disease processes, so they don’t fit the context of C. difficile.

The main point is that Clostridioides difficile makes two toxins that drive disease: toxins A and B. These are glucosyltransferases that inactivate Rho family GTPases in intestinal epithelial cells, causing collapse of the actin cytoskeleton. This leads to loss of cell junctions, cell damage, and mucosal injury. Toxin A acts as an enterotoxin, promoting inflammation and secretory diarrhea, while toxin B is a potent cytotoxin that causes extensive cytopathic damage to the lining. The combined effect results in the characteristic pseudomembranous colitis seen in C. difficile infections. Other choices reference toxins from different organisms or unrelated disease processes, so they don’t fit the context of C. difficile.