A 40-year-old develops hemolytic anemia, hemoglobinuria, and acute kidney injury following a clostridial septicemia. The toxin directly responsible for massive intravascular hemolysis is:
- A Theta toxin (perfringolysin O)
- B Alpha toxin (phospholipase C / lecithinase) ✓
- C Kappa toxin (hyaluronidase)
- D Lambda toxin (protease)
Correct answer: B. Alpha toxin (phospholipase C / lecithinase)
Explanation
Clostridium perfringens alpha toxin (lecithinase / phospholipase C) cleaves phosphatidylcholine in red blood cell membranes, causing massive intravascular hemolysis. This is the major lethal toxin in gas gangrene and also causes the storm hemolysis of post-abortal septicemia. Theta toxin (perfringolysin O) is a cholesterol-dependent cytolysin contributing to tissue necrosis but is less central to hemolysis than alpha toxin. Kappa and lambda toxins are invasins.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.