Vibrio Bacteriology Question And Answers

Vibrio Long Essays

Question 1. Describe morphology, cultural characteristics, taxing, and laboratory diagnosis of vibrio cholera.

Vibrio cholera Morphology:

  • Vibrio cholera is a gram-negative, non-capsulated, and non-sporing organism.
  • It is motile and possesses a single polar flagellum, thus called darting motility.
  • Size: 1.5 mm x 0.2 – 0.4 mm.
  • Shape: curved or comma-shaped rod.

Vibrio- Vibirio cholerae

Vibrio cholera Cultural Characteristics:

  • Vibrio cholera is strongly aerobe
  • Grows within a temperature range of 16-40°C and alkaline pH of 8.2

Vibrio- Vibirio choleraeCultural characteristics

Vibrio cholera Toxins:

  • Vibrio cholera produces enterotoxin known as cholera toxin (CT)
  • It is heat labile
  • Protein in nature.
  • Molecular weight – 90,000
  • It has two fractions.
    • A (active) subunit – one.
    • B (binding) subunit – five.
  • Its production is determined by phage integrated with bacterial chromosomes.

Vibrio cholera Mechanism:

Vibrio- Vibirio cholerae mechanism

Read And Learn More: Microbiology Question and Answers

Laboratory diagnosis:

1. Direct microscopy.

  • Not reliable.
  • Characteristic motility of the vibrios is demonstrated by dark field or phase contracts microscope.

2. Culture.

  • Nutrient agar.
    • Shows moist, translucent, round disc colonies.
  • Selective media – Monsur’s GTTA media.
    • Shows small, translucent colonies with a greyish-black center and turbid halo.
  • Macconkey’s agar media.
    • Shows initially colorless colonies which later become reddish.

3. Agglutination test

  • Colonies from selective media are picked up with a straight wire and tested by slide agglutination with cholera 0 subgroup I serum.
  • If positive, the agglutination test is repeated using monospecific Ogawa and Inaba sera for serotyping.

4. Serological tests – includes.

  • Agglutination using live or killed vibrio suspension.
  • Indirect haemagglutination.
  • Vibriocidal test.
  • Antitoxin assay.

5. Biochemical test.

  • Fermentation of glucose, mannitol, maltose, sucrose.
  • Indole positive.
  • Reduction of nitrates.
  • Catalase and oxidase positive. Voges – Broskauer negative.

Vibrio Short Essays

Question 1. Cholera.

Cholera Etiology:

  • Cholera is caused by vibrio cholera.
  • The route of infection is contaminated food and water.
  • Alkaline pH in the stomach and intestine appears to be more easily infected.

Cholera Pathogenesis:

Vibrio- Cholerae Pathogenesis

Cholera Features:

  • Diarrhea is the major symptom.
  • Feces contain epithelial cells, mucus and large number of V. Cholera.
  • Profuse watery diarrhoea – rice water stools occur.
  • In severe cases, there may be one liter of fluid loss each hour.
  • Abdominal pain.
  • Death due to electrolyte abnormalities and fluid loss.

Treatment, Prevention, and Control:

  • Intravenous administration of fluids.
  • Oral administration of a solution containing glucose and electrolytes.
  • Antibiotics.
    • Doxycycline – In adults.
    • Sulphamethethoxazole – In children.
    • Furazolidone – In pregnant women.
  • Improved – hygiene.
  • Water purification, immunization.

Vibrio Short Question And Answers

Question 1. Whooping cough.

Whooping cough is predominantly a childhood disease.

Whooping cough Causative agents:

  • B. Pertusis – 95% cases.
  • B. Parapertusis – 5% cases.
  • B. Bronchiosepetica – 0.1% cases.

Whooping cough Features:

  • Incubation period – 1 – 2 weeks.
  • Infection is transmitted by droplets.
  • Diseases usually last for 6 – 8 weeks.
  • It consists of 3 stages.

1. Catarrhal.

  • Clinical diagnosis is difficult.

2. Paroxysmal.

  • Whooping cough occurs.

3. Convalescent.

  • Frequently and severity of coughing decreases.

Whooping cough Complications:

  • Subconjunctival hemorrhage.
  • Subcutaneous emphysema.
  • Bronchopneumonia.
  • Convulsions, coma.

Whooping cough Prophylaxis:

  • Pertussis vaccine is given.
  • Three injections at intervals of 4 – 6 weeks are given before the age of 6 months.
  • A booster dose is given at the end of the first year.

Question 2. Castaneda’s method of culture.

It is used for Brucella.

Culture Composition:

  • It contains:
    • Liquid media – trypticase soy broth.
    • Solid media – trypicase soy agar.

Culture Method:

  • Blood is inoculated into liquid media in a bottle.
  • Incubate it in an upright position.
  • The bottle is tilted and subcultured by solid media.
  • Incubate it again in an upright position.

Brucella Castaneda's medium

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