Evaluation of Diagnostic Potential of Recombinant Outer Membrane Protein (rOmp28) of Brucella Melitensis for Serodiagnosis of Ovine and Caprine Brucellosis

Brucella melitensis is the main causative agent of brucellosis in small ruminants. The diagnosis of brucellosis is mostly done by isolation of bacteria from aborted material, udder secretions or from tissues of infected animals. The presumptive diagnosis of Brucellosis is attempted by elucidating the serological responses to Brucella antigens. The present study was designed to evaluate the diagnostic potential of rOmp28 antigen of Brucella melitensis for ovine and caprine brucellosis. A total of 163 clinical samples (n=79 samples of ovine and n=84 samples of caprine) were tested in an indirect plate-ELISA format using rOmp28 antigen. Results of rOmp28 antigen based indirect ELISA were also compared with the native antigens [cell envelope antigen (CE) and whole cell sonicated antigen (SA)] based ELISA and with conventional Standard Tube Agglutination Test (STAT). Recombinant Omp28 antigen showed high sensitivity and specificity i.e., 71.4%, 97.7% for ovine samples and 74%, 87.8% for caprine samples as compared with CE antigen (40%, 75%) and (44%, 67.6%) and SA antigen (37.1%, 84%) and (42%, 70.5%) for ovine and caprine samples respectively. This study demonstrated that rOmp28 can be a good candidate antigen in the serodiagnosis of ovine and caprine brucellosis in India and also further in the development of rapid field-adaptable diagnostic assay for screening of ovine and caprine brucellosis.