16. vibrio cholera
- 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.