Brucellosis Diagnosis and Infection

Brucella Test (Rose Bengal Test)

• Brucella antigens are used in a slide agglutination test to detect the presence of bacterial agglutinins, indicating bacterial infection or previous exposure.
• The test is recommended as a screening procedure to establish the presence or absence of antibody.

Brucellosis

• Brucellosis is a zoonotic infection caused by Brucella bacteria.
• The bacteria are transmitted from animal to human through affected food products or direct contact with infected animals.
• Clinical manifestations of the disease include:
  • High fever
  • Pain in joints
  • Anorexia
  • Weight loss
  • Fatigue
  • Sweating
  • Depression
  • Headache

Reagents and Materials

• Reagents:
  • Rose Bengal Brucella antigen (0.5% phenol)
  • Positive control (0.01% sodium azide)
  • Negative control (0.01% sodium azide)
• Materials:
  • Brucella antigen, Rose Bengal stained
  • Positive control
  • Negative control
  • White glass slide
  • Stirring sticks
  • Pipettes for dispensing (40µl) serum
  • Timer

Specimen Collection and Preparation

• Collect 5 ml whole blood samples aseptically from the patient.
• Allow blood to clot and remove serum as soon as possible to prevent excess hemolysis.
• Store serum in the freezer until testing can be performed.

Procedure

• Allow reagents and serum samples to reach room temperature for testing.
• Shake the antigen bottle gently to ensure a uniform suspension.
• Place 40 µl of sample serum onto the selected ring of the slide.
• Place one drop of the Rose Bengal antigen onto the serum sample.
• Mix the serum sample with the Rose Bengal antigen using a stirring stick.
• Repeat the steps using the positive and negative controls instead of the serum sample.
• Gently rock the slide for 2 minutes (an automatic rotator can also be used).
• Observe for agglutination after 2 minutes from the beginning of shaking (this is the optimum time limit).

Results

• Negative: No agglutination.