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Vibrio cholerae

Vibrio cholerae. Amy Tenaglia, Atusa Sedehi, Gabby W. Vibrio Cholerae. Gram negative Facultative anaerobe Curved-shaped rod One polar flagellum Housed by zooplankton in both fresh and salt water Found in water contaminated with fecal matter Cholera Toxin. A-B Exotoxin

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Vibrio cholerae

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  1. Vibriocholerae Amy Tenaglia, Atusa Sedehi, Gabby W

  2. Vibrio Cholerae • Gram negative • Facultative anaerobe • Curved-shaped rod • One polar flagellum • Housed by zooplankton in both fresh and salt water • Found in water contaminated with fecal matter • Cholera Toxin

  3. A-B Exotoxin Causes Cholera in humans Produced by the CTXf bacteriophage A subunit (activating) A1 domain: enzymatic active site A2 domain: a-helical tail B subunit (binding) Pentameric ring around central pore Cholera Toxin

  4. Mechanism of Toxin • Subunit B binds to GM1 ganglioside receptor on the intestinal cell • Subunit A is engulfed by the cell • Domains A1 and A2 separate, making A1 an active enzyme • Domain A1 enters cytosol and activates G protein to stay in certain form • Constant production of cAMP

  5. Mechanism Continued • High cAMP levels causes intestinal cell to secrete ions (Cl-, K+) • Sodium (Na+) loves ions, NaCl • Water loves NaCl • Water is pulled out of intestinal cells, Diarrhea • Cholera

  6. How is the Infection Diagnosed? Isolated from stool or vomit Cholera antibodies in the blood Fecal leukocyte stain Stool culture Thiosulfate Citrate Bile Salts Sucrose (TCBS) agar

  7. How is the Infection Treated? • Cholera is treated by replacement of the salts and fluids that were lost during the severe diarrhea • Oral rehydration solution- Prepackaged sugar and salts that are to be mixed with water and drunk in bulk • This solution is used to treat the dehydration caused by diarrhea • For severe cases: - Intravenous fluid replacement • Antibiotics-Tetracycline or Doxycycline

  8. Long Term Consequences? • In a few cases, as a result of dehydration: • kidney failure • shock • Death-Fewer than 1%

  9. Natural Habitat • Brackish rivers, costal waters • Raw/undercooked shellfish or seafood

  10. Found in contaminated water • Concern in areas hit by hurricanes

  11. Prevalence • Infective dose: 1 million organisms to cause illness • Sanitation facilities in the U.S. have nearly eradicated the disease • Sporadic cases due to shellfish contamination • Concern for areas hit by hurricanes • Countries with poor sanitation, poverty, war, crowded conditions

  12. Benefits to Environment • Chitinase- enzyme that breaks down chitin (shell structure) • Works to control the amount of shells and cocopods in bays and estuaries • Toxins may play a role in osmoregulation for cocopods (ability to move from fresh to salt water)

  13. Benefits to Humans • No real benefits • Oligosaccharides- defensive factor against diarrheal infections- found in breast milk • pH of stomach kills many of the microbes

  14. Governmental Concerns • Enhance surveillance • Investigate outbreaks • Implement preventative measures • Proper identification techniques • Information on diagnosis, treatment, prevention • Educating the public • Providing medical supplies • Water and sewage treatment • Testing seafood, monitoring safety

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