CHOLERA

1. VIBRIO CHOLERA
RATHEESH R.L

3. MORPHOLOGY

4. CULTURAL CHARACTERISTICS
They are aerobics facultative
anaerobes growing well in the
temperature of 37 degree C and in the
Ph of 7.4 - 9.6

5. ORDINARY MEDIA
 NUTRIENT AGAR MEDIUM
 MACCONKEY AGAR MEDIUM
 BLOOD AGAR MEDIUM
 GELATIN STAB CULTURE

6. SPECIAL MEDIA
 TRANSPORT MEDIA
 VR medium
 Bile peptone transport medium
 Cary blair medium
 ENRICHMENT MEDIA
 Alkaline peptone water
 Monsur’s medium
 PLATING MEDIA
 Alkaline bile salt agar medium
 Monsur’s gelatin taurocholate trypticase tellurite agar medium
 Thiosulphate citrate bile sucrose agar medium

7. ORDINARY MEDIA
 NUTRIENT AGAR MEDIUM
After overnight incubation round,
moist, translucent, bluish colonies will be
appear with 1-2mm size.

8. MACCONKEY AGAR MEDIUM
 Colorless colonies will be form after that it
will change to pink color.

9. BLOOD AGAR MEDIUM
 A zone of green discoloration appears
around the colonies at first and later it
become clear.

10. GELATIN STAB CULTURE
 After three days of incubation a white line of
growth appears in the medium

11. TRANSPORT MEDIA
 VENKATRAMAN - RAMAKRISHNAN MEDIUM
 This is an ideal transport medium.
 The organism will be viable in this
medium for several weeks without
multiplication

12. ENRICHMENT MEDIA
 ALKALINE PEPTONE WATER
Rapid growth occurs in about 6 hours with
formation of thick surface pellicle.

13. PLATING MEDIA
 ALKALINE BILE SALT AGAR MEDIUM
It is a modified nutrient agar medium and the
colonies are similar that appears in the nutrient agar
medium.

14. MONSUR’S GELATIN TAUROCHOLATE
TRYPTICASE TELLURITE AGAR MEDIUM
 After 24 hours of incubation small colonies will be
formed with 1-2 mm in size and grayish color with
black centers.
 The size will be increased to 3-4 mm after 48 hours
of incubation.

15. THIOSULPHATE CITRATE BILE SUCROSE AGAR
MEDIUM
 In this medium large colonies will be formed in
yellow color.
 Later the yellow color will be changed to green
color.

16. PATHOGENESIS
 Vibrio cholerae is the causative agent of the
diarrheal disease cholera.
 The disease is characterized by sudden
effortless vomiting, profuse rice water stool
followed by rapid dehydration.

17.  Infection occurs in humans via oral route by
ingestion of contaminated food or water.
 Incubation period is 6hours to 3 days.
 The ingested micro organism reaches to the
stomach and the multiplication occurs in the small
intestine.
 After the growth and multiplication it starts to
produce toxins namely, “cholera toxin” or “cholera
enterotoxin” or “choleragen”

18.  This toxins cause the hyper secretion of glands in
the intestine and resulting in large amount of
intestinal fluids in the intestinal lumens.
 The toxin also increases the capillary permeability
leading to edema.
 On the same hand it produces proteolytic enzymes,
which help the organism to penetrate the covering
of GI tract and causes the diarrheal disease among
humans.

19.  The stools are rice water similar which containing
mucous, epithelial cells and large number of
vibrios.
 The massive loss of electrolytes from the body
leads to metabolic acidosis, muscle cramps, anuria,
acute tubular necrosis, shock and some times
death.
 The disease may last for 4-5 days with an average
fluid loss of 15-20 liters per day.

20. LABORATORY DIAGNOSIS
 Hematological investigations:
no significant abnormalities
 Bacteriological examination
1, microscopic examination
2, cultural studies
3, biochemical test
4, slide agglutination test

21. MICROSCOPIC EXAMINATION
 Under the microscope can observe gram negative
comma shaped bacilli.

22. CULTURAL STUDIES
 Ordinary media, transport media and enrichment
media can be use for the culture studies.
 In macconkeys medium pale color colonies will
developed.
 In mansur medium colonies will be formed with
black centers.

23. BIOCHEMICAL TESTS
 Sugar fermentation test: fermentation of glucose,
sucrose and maltose will occur with the production
of gas.
 Nitrate reduction test: positive
 Iodole test: positive
 Catalase test: positive
 Oxidase test: positive
 Motility test: positive

24. SLIDE AGGLUTINATION TEST
 The specimen from a selective media is placed on
a microscopic slide and add a drop of normal saline
over that and then observe under a microscope
after adding one drop of antiserum over the
specimen.
 Presence of clumps indicates the positive test.

26. TREATMENT
 Adequate fluid and electrolyte replacement is
necessary for such patients which is known as fluid
replacement therapy.
 Oral rehydration therapy.