Faculty of Veterinary Medicine, Urmia University Veterinary Research Forum 2008-8140 14 12 2023 12 01 Genetic diversity of Brucella melitensis isolates from sheep and goat milk in Iran 649 657 706645 10.30466/vrf.2023.1988859.3768 EN Heidar Rahimi Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran Amir Tukmechi Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran 0000-0003-3080-4723 Ehsan Rashidian Department of Microbiology, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, Iran Journal Article 2023 01 31 The genetic diversity of <em>Brucella </em>strains has not been fully understood. To investigate this, the genetic characteristics of 64 isolates of <em>Brucella melitensis</em> from sheep and goats’ milk were studied using random fragment length polymorphism (RFLP) and multiple locus variable-number tandem repeat analysis (MLVA-16) methods developed in Orsay, France (MLVA-16<sub>Orsay</sub>). The RFLP analysis revealed that all 64 isolates were of biovar one. The MLVA-typing showed that one sample was simultaneously infected with two strains of <em>B. melitensis </em>and the genotype of 65 isolate was analyzed. Four genotypes (47, 42, 43, and 63) were identified using MLVA-8 (panel 1), whereas six genotypes (138, 125, 116, 108, and two unknown genotypes) were identified using MLVA11 (panels 1 and 2A). From the review of MLVA-16 (panels 1, 2A, and 2B), panel 2B showed a very high discriminatory power. Two loci of Bruc04 and Bruc30 from this panel had diversity index values higher than 0.71 and the average diversity index was 0.619. So MLVA-16<sub>Orsay</sub> 34 showed the genotype indicating a low genetic homogeneity among the isolates. The findings of MLVA genotyping of the isolates suggest that strains of <em>B. melitensis </em>isolated from the milk of small ruminants in Iran are 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 to indicate the potential use of MLVA genotyping for simultaneous detection of specimen contamination using two different <em>B. melitensis </em>biovars. Brucella melitensis Goat Milk MLVA Sheep https://vrf.iranjournals.ir/article_706645_825dd567ba8083f96f443f8a7be0afa0.pdf