Genotyping of human Brucella isolated by multiple locus variable numbers of tandem repeats analysis

Objective To analyze genotypes of Brucella isolated in Shanxi Province using multiple locus variable numbers of tandem repeats analysis(MLVA). Methods In brucellosis monitoring points in Shanxi Province in 2012 and 2013, blood samples were collected from brucellosis patients, and blood culture was done, then traditional identification of biological classification was carried out. MLVA-16[two groups: panel 1, panel 2 (including panel 2A, panel 2B)]was used for typing of Brucella, then genotyping results were cluster analyzed. Results In 2012 and 2013, a total of 47 Brucella were isolated, all of strains were Brucella melitensis type 3 and highly homologous, clustering in panel 1 to the East MediterraneanBrucella melitensis group. The strains were divided into groups A and B, and group A was an advantageous gene group; variabilities of Bruce04, Bruce16 and Bruce30 in panel 2B were higher. Conclusions The result of MLVA for Brucella is identical or similar in same year and adjacent areas, which is significant for analyzing source of infection, epidemics and outbreaks of brucellosis. Genotypes show variation mainly at panel 2B loci (Bruce04, Bruce16 and Bruce30); these three loci are most useful for typing Brucella in Shanxi.