Felis ISSN 2398-2950

Clostridium tetani

Synonym(s): C. tetani

Contributor(s): Melissa Kennedy

Introduction

Classification

Taxonomy

  • Genus: Clostridium.
  • Family: Bacillaceae.

Etymology

  • Gr :tetanos- tension.

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Clinical Effects

Epidemiology

Habitat

  • The spores of C. tetani are widely distributed in soil.
  • Often transiently present in the gastrointestinal tract of animals.

Lifecycle

  • Spores germinate in an anaerobic environment, such as devitalized tissue.
  • Proliferation of the bacterium results in neurotoxin production.

Transmission

  • From soil.
  • Spores are introduced into wounds.

Pathological effects

  • Dogs, and even more so cats, relatively resistant to tetanus.
  • The endospores enter wounds or trauma sites, eg through the umbilicus, or after castration, or into the uterus after dystocia.
  • Anaerobic conditions are provided by the presence of facultative anaerobes and the spores germinate.
  • The cells multiply and produce 2 exotoxins: tetanolysin (a hemolysin), which is apparently insignificant, and the neurotoxic tetanospasmin, which travels along the peripheral nerves and binds to specific gangliosides of the motor nerve terminals and causes spastic paralysis and the characteristic spasms.
  • Toxin may enter blood stream and affect most susceptible motor nerve centres, which are those that serve the head and neck - first sign in this case is protruding 3rd eyelid, tetanic spasm of facial and jaw muscle (lock jaw).
  • Wounds near head   →   more rapid onset of generalized signs.
  • Localized tetanus can occur - stiffness of muscle or entire limb near wound site.

Other Host Effects

  • Transient in the intestinal tract; commensals unless they gain access to wounds or traumatized tissue.

Control

Control via animal

  • Clean and debride wounds .

Control via chemotherapies

  • Supportive care.
  • Sedatives.
  • Penicillin G Benzylpenicillin.
  • Antitoxin:
    • Binds unbound toxin.
    • Doesn't hasten recovery, as bound toxin is cleared slowly.

Vaccination

Other countermeasures

  • Prompt administration anti-toxin Therapeutics: immunological preparation - but not into CNS.
  • Some have suggested intra-thecal administration of anti-toxin to horses, but this is not currently recommended.

Diagnosis

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Further Reading

Publications

Refereed papers


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