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
