Brucellosis is a widespread zoonotic infection, and in recent years human brucellosis emerged as one of the most significant public health concerns in Xinjiang, China. In these cases, B. melitensis is the major pathogen. In order to explore the genetic features of B. melitensis in Xinjiang, five suspected B. melitensis strains isolated in Northern Xinjiang were selected for whole-genome sequencing and analysis in this study. The results showed that all five strains belonged to B. melitensis. Phylogenetic analysis based on whole genomes showed that the five samples had significant differences from other B. melitensis strains from Europe and other Asian countries, but these strains were highly homologous with strains previously isolated in China. Among them, BY38 and BY72 had the closest phylogenetic relationship with B. melitensis M28, while AKS, ALT2 and ALT3 had the closest phylogenetic relationship with B. melitensis NI. Meanwhile, the SNPs and InDels that exist in the five strains make traceability possible, and the missense variant genes in COG analysis can help researchers understand the genetic and/or phenotypic differences among the strains, such as amino acid transport and metabolism (COG category E) indentified in this study. This study showed the genetic characteristics of B. melitensis strains from Xinjiang, and also provided basic data for researches on the prevention and control brucellosis in China.

Key words: COG analysis, Missense variant, SNP, Whole-genome sequence