MLVA typing of <i>Brucella melitensis</i> and <i>B. abortus</i> isolates of animal and human origin from India

Brucellosis is a widely prevalent zoonotic disease of major public health significance. A collection of <i>Brucella melitensis</i> and <i>Brucella abortus</i> field isolates of animal and human origin were subjected to MLVA-15 typing followed by phylogeography studies. The MLVA-15 analysis of <i>B. melitensis</i> (<i>n</i> = 65) field isolates resulted in 48 different profiles. The panel I marker bruce45 was found to be most conserved, while the rest of the panel I markers showed low to moderate length polymorphism. Among the panel II markers, bruce04, bruce16 and bruce30 showed a high discriminatory index. The MLVA-15 typing of 13 <i>B. abortus</i> field isolates revealed 13 different genotypes with panel II markers showing higher discriminatory ability vis-à-vis panel I. The minimum spanning tree analysis (MST) in comparison with isolates from the international database revealed that all <i>B. melitensis</i> and <i>B. abortus</i> isolates from this study belonged to the ‘Eastern Mediterranean’ and the ‘abortus C’ lineage, respectively. The MLVA-15 typing could differentiate field isolates of <i>B. abortus</i> and <i>B. melitensis</i> originating from different regions, reaffirming the technique’s potential of high resolution and suitability for local epidemiological studies. The MLVA scheme also has the advantage of comparison of local isolates with a worldwide database, allowing for phylogeographical studies.