In silico design and in vitro development of a highly accurate test to detect Brucella species

Authors: HOSEIN SAFARI, SETAREH SHAHNAZARI, MAYSAM MARD-SOLTANI, SOMAYEH TAVAKOLI, BAHMAN KHALESI

Abstract: Background: Conventionalmethods of detecting Brucella spp. suffer from technical and biological complications. Besides, newly characterized species of the genus Brucella could be neglected by previously designed polymerase chain reaction (PCR) tests. Therefore, a more accurate PCR-based test seems to be imminently needed. Materials and methods: Blood samples were collected from 39 patients diagnosed with brucellosis and 25 healthy controls. Multiple sequence alignments (MSA) were performed on 500 Omp2-related protein and gene sequences. Thereafter, specific primers were designed and synthesized for the regions with highest conservancy. The collected samples were assessed by PCR test. To overcome the cross-reactivity issue, PCR thermal program was optimized regarding annealing time and temperature.Results: The MSA results indicated that the N terminus region of the Omp2 protein (DNA 5' end) is associated with highest conservancy. Primers with highest specificity were designed and synthesized. A two-step PCR reaction was successfully designed and optimized. The desirable bands were observed in clinical samples with high accuracy. Conclusion: It should be pointed out that using a precisely designed primer pair would bring about early infection detection, more success to detect all natural variants and higher cost-to-efficacy ratio in comparison to other detection methods.

Keywords: Brucellosis, diagnosis, Omp2, primer design, multiple sequence alignment, PCR

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