Ann Short Rep | Volume 4, Issue 1 | Research Article | Open Access

Identification and Differentiation of Malaysian Brucella Isolates Based on rpoB Gene Sequence Analysis

Azura Mohd Noor1*, Sumarni Mohd Ghazali2, Jama’ayah Mohd Zahidi1, Tay Bee Yong1, Rohaidah Hashim1 and Norazah Ahmad1

1Department of Bacteriology, Infectious Diseases Research Center, National Institute of Health, Malaysia
2Department of Biomedical Epidemiology, National Institute of Health, Malaysia

*Correspondance to: Azura Mohd Noor 

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Brucella sp. causes brucellosis in both humans and animals. Identification of this pathogen remains controversial due to the instability of the phenotypic characteristics among Brucella isolates which complicates the identification and subdivision of this genus down to the species level and biovar determination. In this study, we report the potential of rpoB gene sequence analysis as an alternative tool in the identification and differentiation of Brucella sp. in Malaysia. The rpoB gene marker was able to distinguish 21 Brucella isolates into 10 distinct RpoB marker patterns namely RpoB 1 to RpoB 10. Two isolates clustered into RpoB 1 pattern and 12 isolates clustered into RpoB 2 pattern were identified as Brucella suis and Brucella melitensis, respectively, by rpoB gene sequence and phylogenetic tree analysis. Three strains with RpoB 3 and one from RpoB 4 pattern were suggested to be Brucella melitensis as its rpoB sequences were closely related and almost identical to the three published Brucella melitensis (Accession number CP001851.1, CP002459.1 and CP001488.1). The remaining four isolates from RpoB 5 until RpoB 8 patterns were identified as Brucella melitensis but probably with different biovar. RpoB 9 and RpoB 10 patterns belong to the published Brucella abortus (Accession number AM040264 and CP003176.1) and Brucella canis (Accession number CP003174 and CP000872.1), respectively. B. melitensis was the most common species in the study indicating that human brucellosis cases in Malaysia is probably affected mainly by this species. In conclusion, this study shows that the rpoB marker is potentially be implied to identify and differentiate local Brucella sp. in Malaysia.


Brucellosis; Brucella; RpoB; Codon; Phylogenetic tree


Noor AM, Ghazali SM, Zahidi JM, Yong TB, Hashim R, Ahmad N. Identification and Differentiation of Malaysian Brucella Isolates Based on rpoB Gene Sequence Analysis. Ann Short Reports. 2021; 4: 1061.

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