Clostridium Tetani


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Clostridium Tetani

  1. 1. Clostridium tetani<br /><br />
  2. 2. History<br />1884- Arthur Nicolaier isolated the bacterium<br />Antonio Carle & Giorgio Rattone showed transmissibility by injecting human pus into rabbit sciatic nerve<br />1897- Edmund Nocard found the antitoxin could prevent and treat tetanus<br />P. Descombey developed the tetanus toxoid vaccine in 1924 <br />
  3. 3. Cases<br />Around the early1800s- 200 cases per 100,000 people<br />By1947- 0.4 cases per 100,000 people<br />Decrease because of wound care improvements & vaccine<br />
  4. 4. Characteristics<br />Gram +<br />Rod shaped<br />Endospore<br />Vegetative cells killed from O2 exposure<br />Spores survive in long periods of O2<br />Drum stick shape<br />May stain gram – or gram variable in older cells<br />Leaky peptidoglycan layer, layer too thin or too thick<br />11 known strains<br />Differ in production of toxin & flagellar antigens<br />
  5. 5. Habitat<br />Live in all anaerobic habitats including soil, feces & intestinal tracts of various animals<br />Especially found in heavily manured soils <br />
  6. 6. Virulence Factors: Toxin<br />Tetanospasmin, diphtheria & botulism toxin top 3 most poisonous to humans<br />Spores introduced through wound <br />A-B Toxin is produced by spores during cell stages: growth, sporulation & lysis<br />Moves through path from local site to CNS<br />Released through natural cell lysis<br />Toxin is synthesized as a150kDa polypeptide chain <br />
  7. 7. Virulence Factors Cont… Toxin<br />Chain cleaved by a protease into a 100kDa heavy chain (fragment B) & a 50kDa light chain (A)<br />Connected by a disulfide bridge<br />B fragments bind to ganglioside<br />A fragments have toxic enzymatic activity<br />No useful function for C. tetani<br />Heat & O2 labile<br />
  8. 8. Path of Tetanospasmin<br />Toxin blocks the release of inhibitory neurotransmitters by cleavage of synaptobrevin II (protein)<br />Required to inhibit nervous impulses<br />Continuous contractions are produced<br />Binds to peripheral nerve terminals<br /> Transported within the axon <br />Cross synaptic junctions until it reaches the CNS<br />Rapidly fixed to gangliosides at the presynaptic inhibitory motor nerve endings<br />Taken up into the axon by endocytosis<br />
  9. 9.<br />
  10. 10. CNS<br /><br />
  11. 11. Tetanus<br />Lethal dose of tetanospasmin is insufficient to provoke an immune response<br />Lab tests aren’t used<br />Physical exam for stiffness, pain & muscle spasms<br />Leads to death in 1:10 cases<br />The time between the injury and symptoms is less than 2 weeks<br />
  12. 12. Symptoms<br />1809: Sir Charles Bell's portrait of a soldier dying of tetanus. <br />Severe, painful spasms<br />Rigidity of voluntary muscles<br />Difficulty swallowing<br />Death follows due to inability to breathe<br /><br />
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  14. 14. Treatment<br />Antimicrobial drugs eradicate the bacterium <br />Ex. Penicillin<br />Severe cases used sedation & mechanical ventilation<br />Recovery can be several months usually in the ICU so vital functions can be monitored<br />
  15. 15. Prevention<br />DT is given instead of DTaP if the pertussis isn’t tolerated well<br />Td is the booster shot given & Tdap is the same with pertussis as well<br />Children should get 5 doses <br />Adults should get a booster every 10 yrs or if exposed <br />Tetanus toxoid is inactivated tetanus toxin<br />4 vaccines for diphtheria, pertussis & tetanus<br />DTaP, Tdap, DT, & Td<br />DTaP & DT are given to children under 7<br />Tdap & Td are given to 7 yrs & older<br />
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  17. 17. Recommendation<br />Pregnant women<br />People that work in the dirt or manure<br />Get lots of cuts and scrapes<br />Travelers to foreign countries with hot, damp climates<br />Children who haven’t received the vaccine<br />Adults older than 50<br />People that are not sure if they have received boosters<br />
  18. 18. Conclusion<br />Vaccine has been safe since the 1920s<br />Everyone should get the vaccine and regular booster shots<br />Tetanus is deadly although treatable <br />Prevention is the best tool<br />
  19. 19. Sources<br /><br /><br /><br />