Molecular detection of Brucella in milk using polymerase chain reaction

Brucellosis is a highly contagious disease affecting a wide variety of farm animals. It is also an important zoonosis, and man is often infected following contact with infected animals or the consumption of contaminated milk and milk products. At present, mainly bacteriological and serological detection methods are used. A bacteriological method takes days to weeks to grow the organism besides its health hazard. Serological tests are faster but antigen-antibody interactions can be faulted by non-specific interactions. A method for direct detection of Brucella melitensis in 1 ml of milk was developed on the basis of enzymatic treatment of milk components and subsequent PCR and line probe assay (LPA). After PCR, 3 × 104 CFU/ml sensitivity was obtained by agarose gel electrophoresis and LPA. The safety and sensitivity of LPA combined with its speed suggests the potential of this technique for diagnosis of brucellosis in milk rather than the time consuming classical methods.