Clostridium tetani - Infection

Clostridium tetani

Distinctive tennis-racket shape during spore formation.
It is extremely oxygen sensitive, and spores can survive for extended periods of time in the soil.
Infection typically occurs when wounds encounter contaminated soil.

Wounds provide ideal necrotic and anaerobic environments for C. tetani* growth.

Virulence factors:

Tetanospasmin, is a heat-labile neurotoxin that blocks the release of inhibitory neurotransmitters,* such as GABA and glycine – The neurotoxin is endocytosed, then transported along axons to reach neuronal somas in the spinal cord. – Because it blocks inhibitory neurotransmitter release, neuronal excitatory activity is unregulated. Tetanolysin is another toxin produced by C. tetani.* – It is an oxygen-labile hemolysin thought to promote tissue necrosis.

Infection:

Tetanus is characterized by spastic paralysis:

– This can manifest systemically or locally as lockjaw, grimace (aka, risus sardonicus), and opisthotonos, in which spasms of the extensors of the head, neck, and back produce extreme back extension. Tetanus can also cause fever and sweating. – Cephalic tetanus involves the cranial nerves. – Maternal tetanus is associated with pregnancy, specifically, contamination during medical or spontaneous abortion and delivery. – Neonatal tetanus occurs when infection spreads from the umbilical stump.

Treatment & Prevention:

Vaccination effectively prevents tetanus.
Treatment for infection involves wound debridement and administration of metronidazole and antitoxins are necessary to prevent death.

References

C. tetani (Centers for Disease Control Public Health Image Library).

Clostridium tetani - Infection

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