detection of virulence genes (bvfa, virb and ure) in brucella melitensis isolated from aborted fetuses of sheep and goats.

background and objectives: brucella, causative of brucellosis, has some potential virulence factors involved in brucella replication and its strategies to circumvent the immune response. one of them is the virb gene that encodes the type іv secretion system proteins (t4ss) involved in intracellular replication of organism. brucella virulence factor a ( bvf a), and urease ( ure ) has also been described as being implicated in survival, and virulence in the hosts. the aim of this study was to investigate the b. melitensis virulence factor genes among brucella isolated from aborted fetuses of sheep and goats in fars province, southern iran. materials and methods: a total of 42 isolates of b. melitensis isolated from aborted fetuses between 2005-2011 in fars province of iran was used in this study. pcr assay was performed in order to detect the virb, bvfa, and ure genes using specific primers. results and conclusions: the frequency of bvf a, virb, and ure genes was 78.50%, 73.80%, and 88.09% among all isolates respectively. the results of the present study showed that most brucella isolates from this region have virulence factors genes ( vir b, bvf a, ure ) in their genome, and most b. melitensis had ure genes that has been hypothesized to play a role in the pathogenesis of disease.