BACKGROUND AND OBJECTIVESBrucellosis is a disease that imposes huge costs on the economy and society. It is one of the common diseases between humans and livestock in the world. Sequencing-based molecular methods have been introduced as an effective and repetitive method for bacterial strain typing, which can provide a reliable typing approach for clinical laboratories. The aim of this study is to describe the reproducibility and performance of the Outer Membrane Protein ۳۱ (OMP۳۱) based PCR, as a molecular genotyping tool for Brucella melitensis typing.MATERIALS AND METHODSIn this study, ۱۴۶ samples were taken from human blood samples, bovine and camel lymph nodes, as well as sheep and goat aborted fetuses, including fetal kidney, abomasum, liver, lung, spleen, and heart for bacteriological investigation. The molecular detection of the Omp۳۱ and IS۷۱۱ genes was performed using the isolated B. melitensis (n=۱۴). The sequencing of the Omp۳۱ gene of B. melitensis in the Iranian field isolates was also performed for the whole gene sequencing. The homology of all sequences was then checked with the reported National Center for Biotechnology Information sequences using a basic local alignment search tool for the nucleotide diversity evaluation.RESULTS AND DISCUSSIONThe results showed that Brucella melitensis isolates were recovered from ۱۴ examined cases and confirmed by IS۷۱۱-based PCR method with PCR product of ۷۳۱ bp. The ۱۴ Omp۳۱ gene sequences were clustered as a single branch group with bootstrap support of ۶۳, and they were closely corelated to the Brucella melitensis reference isolates which was determined in NCBI database.CONCLUSIONPhylogenetic analysis based on
OMP۳۱ in animal and human hosts showed genomic similarity in isolates of different origins. Sequencing of this gene can also be used as a tool for identification of Brucella melitensis species and genus