Clostridioides difficile and C perfringens vs C botulinum and C tetani
How to tell Clostridioides difficile and C perfringens and C botulinum and C tetani apart when a board question makes them look alike.
Difficile is pseudomembranes, perfringens is gas/alpha toxin, botulinum is flaccid, tetani is spastic.
Side by side
Gut/wound tissue disease: C difficile causes antibiotic-associated pseudomembranous colitis; C perfringens causes gas gangrene or short-incubation food poisoning.
Neurotoxin disease: botulinum causes descending flaccid paralysis; tetani causes spastic paralysis and lockjaw.
C difficile toxins injure colonic cytoskeleton; C perfringens alpha toxin destroys membranes and muscle tissue.
Botulinum blocks acetylcholine release; tetanospasmin blocks GABA/glycine release from inhibitory interneurons.
Antibiotics plus pseudomembranes points C difficile; traumatic wound with crepitus or reheated meat food poisoning points C perfringens.
Canned food/infant honey plus flaccid paralysis points botulinum; dirty puncture wound plus spasm points tetanus.
The trap
All are spore-forming anaerobes, so the syndrome and toxin target matter more than the genus.
The repair move
For Clostridia, sort by stool, gas wound, flaccid paralysis, or spastic paralysis.
Try a free question
CoreA hospitalized patient develops watery diarrhea after antibiotics. Colonoscopy shows pseudomembranes, and stool testing detects toxins that disrupt the cytoskeleton. Which organism is most likely?
Show answer and explanation
Answer: A. Clostridioides difficile. C difficile causes antibiotic-associated diarrhea and pseudomembranous colitis through toxins A and B.
Why the other choices are tempting
- B. C perfringens causes food poisoning or gas gangrene with alpha toxin.
- C. C botulinum causes descending flaccid paralysis.
- D. C tetani causes spastic paralysis and lockjaw.
- E. B cereus causes reheated rice emesis or diarrheal illness.
Flashcards
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What is the fastest separator for Clostridioides difficile and C perfringens vs C botulinum and C tetani?
Difficile is pseudomembranes, perfringens is gas/alpha toxin, botulinum is flaccid, tetani is spastic.
What clue should make you choose Clostridioides difficile and C perfringens?
Gut/wound tissue disease: C difficile causes antibiotic-associated pseudomembranous colitis; C perfringens causes gas gangrene or short-incubation food poisoning.
Quick answers
What is the fastest way to tell Clostridioides difficile and C perfringens from C botulinum and C tetani?
Difficile is pseudomembranes, perfringens is gas/alpha toxin, botulinum is flaccid, tetani is spastic.
What is the key clue for Clostridioides difficile and C perfringens?
Gut/wound tissue disease: C difficile causes antibiotic-associated pseudomembranous colitis; C perfringens causes gas gangrene or short-incubation food poisoning.
What is the key clue for C botulinum and C tetani?
Neurotoxin disease: botulinum causes descending flaccid paralysis; tetani causes spastic paralysis and lockjaw.
What is the common trap with Clostridioides difficile and C perfringens vs C botulinum and C tetani?
All are spore-forming anaerobes, so the syndrome and toxin target matter more than the genus.