Brucellosis Diagnosis and Infection

Study Notes

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 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:
- 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

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.

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).