OBJECTIVETo understand the genetic and epidemiologic characteristic of Brucella (B.) melitensis strains isolated in Guizhou province in 2010-2012.

METHODSB. genus specific BCSP31-PCR and species-specific AMOS-PCR were used to identify the bacteria strain, while the identified strains were analyzed under MLVA-16 and cluster analysis of B. melitensis strains. The strains were isolated from Guizhou and other provinces.

RESULTSSix B. melitensis strains were identified as B. melitensis using the BCSP31-PCR and AMOS-PCR. Data from the MLVA-16 analysis revealed the differences of repeated numbers at parts of the VNTR locus in the six strains isolated in Guizhou province. The six strains from Guizhou province and 105 B. melitensis strains from other province could be divided into 72 MLVA types(MT). Strain ZY and ZA from Guizhou province were typed as MT63, and LL3, LL4 and LL11 were typed as MT67, while strain SQ was typed as MT72. Data from the clustering analysis showed that ZY,ZA, LL3, LL4 and LL9 were most closely clustered with B. melitensis isolates from Yunnan, Fujian and Guangdong provinces, but strain SQ was genetically remote from other strains.

CONCLUSIONPCR methods, combined with MLVA-16, identified the six B. melitensis strains isolated in Guizhou province in 2010-2012 as B. melitensis biovar 3, with the genetic diversity of the strains showed. Six strains were closely related to the B. melitensis strains from Yunnan, Fujian and Guangdong provinces. The results of this study provided scientific basis for the control and prevention of Brucellosis in Guizhou province.