Clostridium Tetani

Clostridium Tetani


INTRODUCTION:

  • G+ve, noncapsulated
  • Culture – swarming growth

Spores:

  • terminal
  • heat resistant
  • bulging giving a drumstick or tennis racket appearance

The main reservoir of cl. tetani:

  • soil
  • intestine of animals and humans

The main mode of transmission:

  • trauma and contaminated wound
MORPHOLOGY   :
  • Gram positive Bacillus
  • Non capsulated
  • Sporing
  • Obligatory anaerobe
  • Drum stick appearance
  • Spherical & terminal spores
  • Motile by peritrichate flagella except type IV which is non motile.

Tetanus spores are highly resistant to:

  • boiling and autoclaving for 15 minutes at 120 ( Heat) 

CULTURAL CHARACTERSTICS:         

  • Filde’s technique’:
  • Shows swarming growth over the surface of agar. 
  • This property enables the sepration of Cl. tetani from mixed cultures

Incubation period of clostridium tetani:

  • 6-10 days
  • Robertson’s cooked meat broth.
  • Grows well
  • Shows Swarming growth.

On blood agar:

  • alpha-hemolysis is produced
  • Which later develops into 13-hemolysis, due to the production of hemolysin (tetanolysin) 

Produces 2 toxins –

  • tetanolysin (hemolysin)
  • tetanospasmin(neurotoxin)

Tetanotysin (hemolysin) :

  • no role in pathogenesis
  • oxygen labile hemolysin

Tetanospasmin:

  • Oxygen stable
  • Plasma coded
  • Single chain zinc-metalloprotease
  • Release in wound with low redox potential, revitalised tissue
  • Cleave into heavy chain and light chain
  • Light chain active moiety
  • Binds to motor neuron
  • Enters axon
  • transported to nerve cell body
  • Blocks cleavage of synaptobrevin
  • Block release of inhibitory neurotransmitters glycine and GABA of spinal cord
  • Acting pre-synaptically → abolition of spinal inhibition → spread of uncontrolled impulses initiated elsewhere in the CNS
Exam Question
 

INTRODUCTION:

  • G+ve, noncapsulated
  • Culture – swarming growth

Spores:

  • terminal
  • heat resistant
  • bulging giving a drumstick or tennis racket appearance

The main reservoir of cl. tetani:

  • soil
  • intestine of animals and humans

The main mode of transmission:

  • trauma and contaminated wound
MORPHOLOGY   : 
  • Gram positive Bacillus
  • Non capsulated
  • Sporing
  • Obligatory anaerobe
  • Drum stick appearance
  • Spherical & terminal spores
  • Motile by peritrichate flagella except type IV which is non motile.
  • Tetanus spores are highly resistant to:
  • boiling and autoclaving for 15 minutes at 120 ( Heat) 

CULTURAL CHARACTERSTICS:

Incubation period of clostridium tetani:

  • 6-10 days
  • Robertson’s cooked meat broth.
  • Grows well
  • Shows Swarming growth.

Produces 2 toxins –

  • tetanolysin (hemolysin)
  • tetanospasmin(neurotoxin)
  • Tetanotysin (hemolysin)  

Tetanospasmin:

  • block release of inhibitory neurotransmitters glycine and GABA of spinal cord
  • Acting pre-synaptically → abolition of spinal inhibition → spread of uncontrolled impulses initiated elsewhere in the CNS
Don’t Forget to Solve all the previous Year Question asked on Clostridium Tetani

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