Abstract: [Objective]To verify the practicability of genotyping method for the confirmation of atypical Brucella strains, and to provide reference for the discriminative identification of the atypical ones. [Method]The both conventional identification methods and VITEK 2. 0 automatic bacteria identification analysis system were used to carry out the preliminary identification of the clinical Brucella strains from sheep. AMOS-PCR was applied to discriminate the species of the strains. The genotype of the tested strains were determined by using MLVA assay. [Result]Conventional identification results showed that the three tested isolates were Brucella-suspected strains; VITEK 2. 0 automatic bacteria identification analysis system confirmed that the tested strains all belonged to Brucella genus; AMOS-PCR amplification showed that the strains were Brucella melitensis(B. melitensis); MLVA cluster analysis revealed that the tested strains were close with B. melitensis biovar 2 and belonged to Eastern Mediterranean lineages; a new genotype (4-4-3-7-5) was found in the Panel 2B and was designated as CN2B-45. [Conclusion]MLVA assay has excellent discriminative power for atypical Brucella strain and is the best strategy for identification of atypical Brucella strain.

Key words: atypical Brucella strain, MLVA, genotyping