Indian Journal of Microbiology Research

Brucella sps are Gram negative, facultative intracellular bacteria causing brucellosis in humans and animals. Since it is a multi-organ disease and symptoms are nonspecific the diagnosis by clinical finding is difficult and can be missed. Many serological tests have been used form the diagnosis of human brucellosis. This study compared the diagnostic value of in-house ELISA and IFA using lipopolysaccharide heat extracted antigen (LPS-HE) and Lipopolysaccharide sonicated extracted antigen (LPS-SE) with STT.

The present study was carried out to evaluate the two different antigenic preparations from smooth strains of Brucella abortus S99 for standardising ELISA and IFA as the alternative test for STT. Standard Tube test antigen and Standard anti brucella serum was obtained from IVRI, Izatnagar were used as controls for standardizing ELISA and IFA. 81 human sera (cases) were collected from people working in organized farms including veterinary staff, 32 animal sera from organized farms mentioned above, 100 human sera (controls) collected from KIMS, Bangalore Blood bank. 100 WIDAL positive samples from Department of Microbiology used to check for cross reactivity. All the serum samples (cases, controls and WIDAL positive samples) were tested with STT.

Out of 81 human sera 8 (9.87%) was found to be positive with SAT showing a titre of ≥ 1:80. Whereas by ELISA, 10 (12.34%) & 9 (11.11%) cases showed positive in LPS –SE and LPS – HE coated plates respectively. The sensitivity and specificity for IFA was 77 and 87.5.

It was found that ELISA was considered to be better test over IFA and STT. It is cheap and reproducible and a specific assay for the diagnosis of Brucellosis.