Polymerase chain reaction (PCR) for detection of Brucella melitensis in goat milk

The diagnosis of brucellosis in goats is frequently difficult to establish. A PCR assay from milk of goat, with primers derived from the omp31 gene sequence of the Brucella melitensis was developed. This PCR resulted in the amplification of a 720 bp PCR product. Out of 54 milk samples collected from goats having history of abortions tested, only 32 (59%) samples could be detected by serology. However, 48 (88.8%) samples were found positive in PCR. This number includes the entire 32 samples tested positive by serology. After a single PCR, sensitivities of 2.2 × 106 and 2.8 × 107 CFU/ml were obtained for detection by agarose gel electrophoresis. In a controlled experiment, the sensitivity and specificity of this PCR was recorded as 90% and 100%, respectively. The specificity and high sensitivity of the PCR assay may provide a valuable tool for the diagnosis of brucellosis in goats.