Kozel: Bacterial neurotoxins Flashcards
Gram-positive bacillus Anaerobic Spore-formers Ubiquitous in soil, water, sewage Normal flora of GI tract of man and animals Produce numerous toxins
Clostridium spp
What kind of toxin is involved in C. tetani?
A-B toxin
The tetanus AB toxin travels to the CNS via (blank) axonal transport
retrograde
Tetanus AB toxin is cleaved into a light (A) and heavy (B) chain. What does the B chain do? What does the A chain do?
B chain binds to ganglioside (sialic acid) receptors;
A chain is an endopeptidase which inactivates proteins that regulate release of inhibitor neurotransmitters, like GABA; this causes spastic paralysis
neurotoxin which causes spastic paralysis; inhibits GABA and glycine release from nerve terminals
tetanus toxin
How to you get tetanus?
either a wound is contaminated by tetanus spores, or they are ingested
What is the most common form of generalized tetanus? What can generalized tetanus effect in advanced disease?
lockjaw (Risus sardonicus); autonomic nervous system
Where does localized tetanus present?
in musculature at site of infection
Systemic effects from infection of umbilical stump
neonatal tetanus
Where is tetanus found?
ubiquitous in soil
human GI tract and in animals
What is used in the tetanus vaccine?
toxoid of tetanus toxin
How to treat tetanus?
eliminate source of toxin by debridement of wound or using metronidazole;
can give antitoxin to neutralize free toxin;
maintain airway and give resp support if needed, or give benzos to prevent spasms
What type of toxin is the botulinum toxin?
AB toxin
The botulinum toxin is cleaved into a light (A) and heavy (B) chain. What does the B chain do? What does the light chain do?
B chain binds to sialic acid receptors on motor neurons; A chain is a protease that inactivates proteins that regulate release of ACh - leads to flaccid paralysis
serotype A botulinum toxin
Botox
