Multilocus variable-number tandem repeat analysis on clinical strains of Brucella isolated in Xinjiang

ObjectiveMultilocus variable-number tandem repeat analysis (MLVA) was conducted for the genotyping of the clinical Brucella strains isolated in Xinjiang to understand the population structure and genetic evolution of the isolated strains.

MethodsA total 24 Brucella clinical strains isolated from 7 prefectures in Xiniang in 2015 and 2016 and 3 standard reference strains were analyzed by MLVA-16 using multicolor capillary electrophoresis to determine sequences types. In order to analyze the genetic relationship among isolated strains, we constructed a minimum spanning tree by using BioNumerics.

ResultsMLVA-16 could distinguish different species of Brucella, the genotype of panel1 and panel2A of 24 strains were all 42 and 108, while locus of panel2B showed polymorphism. The results of the cluster analysis showed that 24 strains were in a branch and in a large branch with Brucella melitensis. Some isolates had close genetic distance with isolates in other regions.

ConclusionThe Brucella melitensis serotype 3 was the major pathogen causing brucellosis in Xinjiang. MLVA-16 using multicolor capillary electrophoresis is a rapid and reliable genotyping method, which can provide evidence for traceability of human brucellosis in Xinjiang.