RESUMO
Objective:To study the multi-locus sequence typing (MLST) gene characteristics of Brucella isolates in Guizhou Province. Methods:Brucella strains, which were isolated from 2017 to 2021 in Guizhou Province (preserved in the Bacterial and Viral Seed Bank of Guizhou Center for Disease Control and Prevention) were identified Brucella and species/types by BCSP31-PCR and AMOS-PCR methods, respectively. MLST method was used for genotyping, and Biometrics 8.0 software was used for cluster analysis of the typing results. Results:A total of 32 strains of Brucella were isolated in Guizhou Province and identified as Brucella melitensis ( B.melitensis) by BCSP31-PCR and AMOS-PCR methods. These strains were classified into 2 ST types (ST8 and ST39) by MLST method, with 28 strains of ST8 type(87.5%) and 4 strains of ST39 type (12.5%). The 28 strains of ST8 type were distributed in 7 cities (prefectures) of Guizhou Province, while the 4 strains of ST39 type were only found in Qianxinan Buyi and Miao Autonomous Prefecture. The cluster analysis results showed that ST8 and ST39 types strains were clustered in a group with the reference strain of B.melitensis, and there was only one nucleotide site difference between ST39 and ST8 types in the glk gene, indicating a close genetic relationship. Conclusions:B.melitensis is the main pathogen of the brucellosis epidemic in Guizhou Province in recent years. ST8 is the dominant MLST genotype in Guizhou Province.