Document Type : Original Article


1 Department of Microbiology, Faculty of Veterinary Medicine, Urmia University

2 Department of Microbiology, Faculty of Veterinary Medicine, Urmia University.

3 Department of Pathobiology, Faculty of Veterinary Medicine, Lorestan University


The genetic diversity of Brucella strains has not been fully understood. In this study, the genetic characteristics of 64 isolates of Brucella melitensis from sheep and goats’ milk were studied by RFLP and MLVA-16 methods assay developed in Orsay, France (MLVA-16Orsay). From examining the isolates with RFLP method, all 64 isolates were diagnosed biovar one. While with the MLVA-Typing method, one sample was simultaneously infected with two strains of B. melitensis and the genotype of 65 isolate was analyzed. Four genotypes (47, 42, 43, and 63) were identified using MLVA-8 (panel 1), whereas using MLVA-11 (panels 1 and 2A), six genotypes, including 138 (26 isolates), 125 (23 isolates), 116 (12 isolates), 108 (2 isolates), and two unknown genotypes, were identified. From the review of MLVA-16 (panels 1, 2A, and 2B), panel 2B shows a very high discriminatory power. Two locus of Bruc04 and Bruc30 from this panel had diversity index values higher than 0.710 and the average diversity index was 0.619. So MLVA-16Orsay 34 showed the genotype indicating a low genetic homogeneity among the isolates. The findings of MLVA genotyping of the isolates indicated that strains of B. melitensis isolated from the milk of small ruminants in Iran were most closely related to the isolates from neighboring countries of the Eastern Mediterranean group. To the best of our knowledge, this is the first study indicating the potential use of MLVA genotyping for simultaneous detection of specimen contamination using two different B. melitensis biovars.


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