Brucella diagnosis by PCR

Brucella is Gram-negative, facultative, intracellular organism which causes serious disease in both humans and animals. The diagnosis of Brucellosis in animals is based on microbiological and serological tests. However, because of zoonotic and fastidious nature of pathogen, isolations are hazardous and time consuming. A variety of serological methods are available but such diagnosis suffers from problems of validity in certain cases.

For rapid diagnosis, quick and reliable identification methods are being developed mainly based on DNA hybridization. Polymerase chain reaction (PCR) is a highly sensitive diagnostic DNA method. PCR assays that have been described for Brucella spp. use primers derived from the 43-kDa outer membrane protein gene of B. abortus, the 16S rRNA gene, insertion sequence IS711, BCSP31 (Brucella Cell Surface Protein) protein gene. PCR assay has been shown to be a valuable method for detecting DNA from various pathogens. It provides a promising option in Brucella diagnosis. High sensitivity has been shown by this technique in detecting Brucella from pure cultures, or when used, alone, or in combination with various labeled probes for species differentiation. More studies are required to test PCR assays from field samples, dead samples, sterile samples, “less number of brucellae cell” samples and in samples contaminated with other species.