1. Vibrio cholerae

2. Cholera

7. Vibrio sp. Gram-negative rods Curves or comma shaped Non-spore forming
Highly motile-single polar flagella
Associated with salt water
Oxidase positive
Facultative anaerobe
Tolerate alkaline conditions to pH9.0
Readily cultivated, Simple nutritional requirements

9. Vibrio Vibrio cholerae -gastroenteritis
Vibrio parahaemolyticus -gastroenteritis, wound infection, bacteremia
Vibrio vulnificus -wound infection, bacteremia

10. Vibrio cholerae Antigenic structure
Common heat-labile flagellar H antigen
O lipopolysaccharide confers serologic specificity
More than 150 O antigen serogroups
Only O-1 and 0139 serogroups cause Asiatic cholera
Three serotypes; Ogawa, Inaba, Hikojima
Two biovars; classic and El Tor

11. 2 biotypes of serogroup O-1
Classical biotype
El Tor biotype.
Serogroup 139

12. V. cholerae - Transmission
feces
water
fresh
salt
food

13. Vibrio cholerae Epidemiology
Epidemic cholera-spread by contaminated water under conditions of poor sanitation
Endemic-consumption of raw seafood
Copepods

15. Vibrio cholerae Pathogenesis Ingest 108-1010 organisms
Non invasive infection of small intestine
Organisms secrete enterotoxin
Watery diarrhea

17. Virulence factors of V.cholerae O1 and O139
Biological effect
Cholera toxin
Hypersecretic of electrolytes and water
Coregulated pilus
Adherence to mucosal cells adhesin
Accessory colonization factor
adhesin
Hemagglutination protease
Releases bacteria from mucosal cells
Zona occludens
Exotoxin
Accessory cholera enterotoxin
Flagellum
Motility
Siderophores
Iron sequestration

18. Cholera toxin Enterotoxin-cholera toxin-CtxAB Encoded by a prophage
Molecular mass of 84,000 daltons
A subunit-ADP-ribosylating toxin
B subunit-bind GM1-gangliosides on enterocytes
A subunit ADP ribosylates Gs-alpha which regulates activation of adenlyate cyclase
Result is persistent increase in cAMP levels
Hyper secretion of Na, Cl, K, bicarbonate and H20

21. Vibrio cholerae-Clinical manifestations
Asymptomatic colonization to fatal diarrhea
Onset 2-3 days after ingestion
Abrupt onset of watery diarrhea and vomiting
Rice water stools
Severe fluid and electrolyte loss-dehydration, metabolic acidosis, hypovolemic shock, renal failure
Death 60% if untreated, 1% if treated for fluid loss

22. Pathogenicity of V. cholera
Dehydration and death
Massive secretion of ions/water into
gut lumen

23. Immunity
Strong immunity after recovery, SIgA

24. Bacteriological Diagnosis
Specimens: stool, vomitus.
Stained smear
Culture: alkaline peptone water of agar plate, and TCBS agar plate.
Quick immunological methods: immunofluorescent “ball” test; PCR.

25. Vibrio-Prevention and Control
Improved sanitation
Fluid and electrolyte replacement
Antibiotic prophylaxis
Improved food handling

26. Vibrio parahemolyticus
One kind of halophilic vibrios; optimal NaCl concentration contained in culture media is 3.5%; hemolysin related to its pathogenicity, can be detected by human or rabbit RBC test (Kanagawa test); cause food poisoning in human beings.
raw sea-food

27. Vibrio parahaemolyticus
Clinical manifestations
Self-limiting diarrhea to mild cholera-like illness
24 hours after ingestion-explosive water diarrhea
Headache, abdominal cramps, nausea, vomiting, low grade fever for 72 hours or more
Uneventful recovery
Wound infections in people exposed to seawater-containing vibrios