Q: Lethal spontaneous gas gangrene is caused by 

 A) Clostridium perfringens 
B) Clostridium septicum 
C) Clostridium botulinum 
 D) Clostridium difficile 
 E) Clostridium tetani


Answer: B

Clostridium contains about 100 species but  only handful are known to cause disease in humans. C. perfringens, botulinum, difficile and tetani are well known. Less described is Clostridium septicum which has unique property to cause spontaneous gas gangrene without any trauma! Source is usually GI tract and is well known to be associated with colorectal cancer. It can quickly spread via its well known necrotic and lethal toxin called alpha toxin, if for any reason gut lining becomes necrotic or inflamed. Its other toxins are beta, gamma and delta toxins.


 References: 

1. Turnbull, TL; Cline, KS (1985). "Spontaneous clostridial myonecrosis". The Journal of Emergency Medicine. 3: 353–360

2. Liechti, ME; Schob, O; Kacl, GM; Caduff, B (2003). "Clostridium septicum aortitis in a patient with colon carcinoma". Eur J Clin Microbiol Infect Dis. 22: 632–634. 

3. Ballard J, Bryant A, Stevens D and Tweten RK (1992). Purification and characterization of the lethal toxin (alpha-toxin) of clostridium septicum. Infection and Immunity. 60(3): 784-790