Salmonella Bacteriology Question And Answers

Salmonella Long Essays

Question 1. Describe etiopathogenesis and clinical features and lab diagnosis of enteric fever.

Enteric fever:

  • Etiopathogenesis:
    • Enteric fever includes:
      • Typhoid fever – caused by salmonella typhi.
      • Paratyphoid fever – caused by salmonella paratyphi.

Virulence factors:

1. Endotoxin.

  • Causes diverse toxic manifestations of enteric fever.

2. Exotoxin – enterotoxin.

3. Capsule.

  • Has anti-phagocytic activity.

Enteric fever Clinical features:

  • Incubation period is 7 – 14 days.
  • Route of infection – contaminated food and water.

1. Typhoid fever – Its manifestations include.

  • Gradual illness
  • Headache
  • Anorexia
  • Congestion of mucous membrane.
  • Hepatosplenomegaly.
  • Step-ladder pyrexia.
  • Relative bradycardia.
  • Leucopenia.
  • Skin rashes called ‘Rose-spots’ appear during the second or third week.

2. Paratyphoid fever.

  • Symptoms are milder than typhoid fever.
  • Septicaemia with suppurative complications occurs.

Read And Learn More: Microbiology Question and Answers

Lab Diagnosis of enteric fever:

1. Isolation of bacilli.

  • For isolation of bacteria specimens are obtained from blood, feces, urine, aspirated duodenal fluid, bile, bone marrow or rose spot.
  • These specimens are then cultured.

Salmonella Isolation of cbacilli culture and features

2. Demonstration of Antibodies.

  • Widal test
    • It is an agglutination for the detection of agglutinins H and 0 in patients with enteric fever

Salmonella Widal test

  • Method:
    • Equal volumes (0.4 ml) of serial dilutions of serum from 1:10 to 1: 640 and H and 0 antigens are mixed.
    • One control tube containing antigen and normal saline is used.
    • All these tubes are incubated in a water bath at 37°C.
  • Results:

Salmonella Lab Diagnosis Result

  • Interpretation:

Salmonella Lab Diagnosis Interpretation

3. Demonstration of circulating antigen.

  • Done by counterimmunoelectrophoresis and ELISA.

Salmonella Short Essays

Question 1. Diseased caused by salmonella.

Salmonella Diseased caused by salmonella

Question 2. Antigenic structure of salmonella.

Salmonella possesses three types of antigen.

Salmonella Antigenic structure of antigen

Leave a Comment