This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Clostridium, Subject name: Microbiology
Gas gangrene is caused by: 
Select and explain. 
A. Clostridium botulium, B. Clostridium perfringens, C. Clostridium difficile, D. Clostridium tetani
B: Clostridium perfringens
Answer: B: Clostridium perfringens 
Explanation: Ans: B (Clostridium perfringens) Ref: Ananthnarayan R, Paniker CKJ. Textbook of Microbiology. 8th Edition. Hyderabad: Universities Press; 2(X)9. Pg. 251Explanation:Gas gangreneCaused byCl. perfringensCl. septic uniCl. odematieunsCl. sporogenesCl histolyticum (Aerotolerant anaerobe)Virulence factorsExotoxins - hemolytic, lethal and necrotic effects, help in spreading of the infectionAlpha toxin (lecithinase) -splits lecithinCollagenase (Kappa)Hyaluronidase - breaks down hyaluronic acid in muscles celtsTheta toxin haemolysinLeucocidin - kills leucocytesGamma, delta, theta, lambda, mu & eta toxinFood poisoningGastroenteritis - Cl. perfringens (type A)Necrotising enterocolitis - Cl. perfringens (type C)* Botulism - Cl. botulinum Acute colitis (Antibiotic associated diarrhoea) - Cl. Difficile