Epidemiological characteristics of Brucella species isolated from different regions of the world using the MLVA genotyping

Objective To study the molecular-epidemiological characteristics of Brucella species isolated from different countries, using the multiple locus tandem-repeat (MLVA) analysis. Methods Eleven variable-number tandem-repeat (VNTR) loci were selected. VNTR strains of Brucella isolated from 48 different countries in 1953-2013, were analyzed by using the BioNumerics software. Unweighted Paired Arithmetic Average method was used to cluster and draw phylogenetic tree as well as the minimum spannin. Results The evolutionary relationship of Brucella phylogenetic tree was consistent with the classical biological typing method. However, the Brucella suis biovar 5 strains were different from the other Brucella suis biovars 1, 2, 3 and 4. Brucella ceti strains were divided into two parts and different from each other. Worldwide epidemics of brucellosis were emerged from 2005 to 2008 under the MLVA11 Orsay analysis. China has been a brucellosis-prone regions, with Brucella melitensis as the main epidemic Brucella species, followed by Brucella abortus. Brucella suis was mainly identified in the southern provinces, but Brucella canis was mainly found in dogs. No human cases were found. Conclusion Molecular-epidemiological characteristics of the Brucella strains were related to factors as time, region and hosts of isolation, which are important to setting up prevention and control programs on brucellosis. Key words: Brucella; Variable-number tandem-repeat loci