Bacterial neurotoxins: tetanus and botulism -Koze Flashcards
Is colistridium spp. gram negative or postive?
Is it a rod or a cocci?
Non spore forming or spore forming?
Where is it ubiquitous?
Is it a normal part of the flora or is it abnormal?
What do they produce?
gram positive rod spore forming water, soil, sewage normal TOXINS
What is the pathogenesis of C. tetani?
Release AB toxin-> retrograde axonal transport to CNS-> cleaved by bacterial protease toe light A and heavy B chains-> B chain binds to ganglioside (sialic acid) receptors and you have A chain.
What is the A chain of C. tetani and what does it do?
it is an endopeptidase that inhibits the release of GABA resulting in spastic paralysis (strong muscle contractions)
If you are unable to regulate GABA as is the case with C. tetani, what does this mean about synaptic activity?
its unregulated
Is C. tetani difficult to grow?
yes
In tetanus, a wound is contaminated by (blank); germination is favored by ….?
spores
necrotic tissue and a poor blood supply
What are the clinical manifestations of generalized tetanus?
- systemic effects from local site
- Risus sardonicus (lockjaw) is most common form
- ANS effects for advanced disease
What is localized tetanus?
effects at musculature at site of infection
What is neonatal tetanus?
system effects from infection of umbilical stump
How do you diagnose tetanus?
clincal diagnosis and history of injury
*NOTE: Most cultures are negative **
Where do you find tetanus?
In soil!!!! and in GI tract of man and animals
What is the vaccine for tetanus ?
toxoid of tetanus toxin
How do you treat tetanus?
- eliminate source of toxin
- antitoxin to neutralize free toxin
- symptomatic care until synaptic function recovers
How do you eliminate the tetanus toxin?
-debridement of wound
-metronidazole
(Tet needs Met)
How do you give symptomatic care for tetanus?
- respiratory support
- benzodiazepines (valium) to prevent spasms
What is the pathogenesis of the botulisim toxin?
A-B toxin is made (a is light chain and B is heavy chain) and is absorbed in gut and carried to blood stream to peripheral nerve synapses-> B chain binds to sialic acid receptors on motor neurons-> A chain remains solo and is dangerous
What is the A chain of the botulinim toxin? Where does it get released? What does it do?
it is a protease that inactivates the release of acetylcholine
What is botox?
serotype A botulinum toxin
What are the two types of botulism?
- foodborne botulism
- infant botulism
How do you get foodborne botulism and what are the signs of it? How do you die from it?
- follows ingestion of preformed toxin in contaminated food
- weakness, dizziness, weakness of peripheral muscles (flaccid paralysis),
- death due to respiratory paralysis
How do you get infant botulism and how does it survive?
in vivo colonization of GI tract of infants
-can survive in GI tract of infants because their GI tracts have limited colonization of normal flora so botulism can compete :)
How can you diagnose botulism?
- demonstrat toxin in food or patient serum or feces
- can isolate bacterium (rarely done)
C. botulinim is common in (blank and blank)
soil and water
Infant botulism is associated with consumption of contaminated (blank). You should avoid honey in children less than (blank) years old
honey
1
Botulism is rare in the (blank) but the most common form of botulism is (blank) botulism
US
infant
How do you prevent botulism?
boil food for 20 mins to inactivate toxin
How can you make botulism a bioweapon?
aerosilize it
How can you treat botulism?
respiratory support
-antitoin to neutralize free toxin
What is the effect of the botulism toxin and what is the mechanism behind it?
- neurotoxin, flaccid paralysis
- blocks neurotransmission by inhibiting release of acetylcholine
What is the effect of the tetanus toxin and what is the mechanism behind it?
- neurotoxin, spastic paralysis
- inhibits GABA and gycine release from nerve terminals
