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Clostridium perfringens

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Clostridium perfringens 

  • Characteristics
    • Common to all bacteria in Clostridia family
    • Gram + rods
    • Obligate anaerobic
    • Spore-forming
      • Spores live in soil
    • Double zone of beta-hemolysis on blood agar
  • Produces lecithinase (an exotoxin)
    • Also known as phospholipase C or alpha-toxin
    • Cleaves membrane lipid lecithins (phospholipase) to cause cell lysis (e.g. hemolysis), tissue necrosis, and edema
    • increases platelet aggregation and adherence molecule expression on WBCs and endothelial cells, resulting in blood vessel occlusion and ischemia in downstream tissues
  • Exposure
    • Penetrating injury
      • Spores enter via contaminated objects (e.g. soil, surgery)
  • Presentation
    • myonecrosis (gas gangrene)
      • Rapid developing necrotizing fasciitis in skin and soft tissue, mediated by lecithinase
      • Tissue damage and necrosis with gas that can be felt on examination (crepitus)
      • Purple-black discoloration of affected limb 
    • Late-onset food poisoning
      • Caused by ingestion of large amounts of spores producing heat-labile enterotoxin
      • Transient watery diarrhea occurs in 10-12 hours after ingestion
        • Occurs slowly since toxin is not pre-formed
    • Hemolysis
  • Treatment
    • Immediate surgical debridement for gas gangrene
      • Surgical emergency, poor prognosis even with treatment
    • Antibiotics
      • Penicillin and clindamycin