Corynebacterium diptheriae

  1. Gram positive rods,arranged in palisades
  2. V or L shaped formations,Cuneiform(chinese letter)pattern.
  3. Metachromatic granules(volutin,Babes ernst,polar granules) stained by -Alberts,Neisser’s,Ponder’s stains.
  4. Form black colonies on tellurite agar(in 2 days),grow rapidly in Loeffler’s serum slope
  5. Virulence factors-Diptheria toxin inhibits protein synthesis in cell.
  6. Shick test-Diptheria susceptibility
  7. Elek’s gel precipitation test-Invitro test to find toxigenicity of diptheria.


  1. Pseudomembranous pharyngitis(grayish white membrane)-Faucial diptheria MC
  2. Bull neck-Cervical Lymphadenopathy
  3. Toxin has special affinity for myocardium,adrenals,Nerve endings(MAN)

DOC:Penicillin,for carriers and prophylaxis-erythromycin.

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