Bacterial Infections USMLE Step 1 Practice Question
A 29 year old man is brought to the hospital after a motorcycle crash. He sustained a deep contaminated thigh wound. Twelve hours later he develops severe pain out of proportion to examination, fever, and rapidly progressive swelling with crepitus. Imaging shows gas in the soft tissues. Which of the following toxins is most responsible for the tissue destruction in this patient?
Answer choices
- ALecithinase that degrades cell membranesCorrect answer
- BPolysaccharide capsule that inhibits phagocytosis
- CHeat stable enterotoxin that increases cyclic GMP
- DExotoxin A that ADP ribosylates elongation factor 2
- ENeurotoxin that blocks glycine release
- FCollagenase that destroys connective tissue architecture
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