Figure 2

Minimum spanning tree (MST) of MLVA showing the genetic relatedness among the isolates included in this study. A categorical coefficient and the priority rule using the highest number of single-locus changes was used for generation of the minimum spanning tree. Each circle in the tree represents a different MLVA type (MVT), with the different MVTs indicated by the number in the circle. MVTs differing by a single VNTR locus are represented by thick short lines, while double-locus variants are shown by thin longer lines and dotted lines for those differing by more than two loci. The number of loci that differ between two MVTs is indicated on the lines linking them together. Clusters were defined as MVTs having a maximum of three differing loci and a minimum cluster size of two. The Norwegian isolates grouped into three main clusters (I, II and III). Cluster I is shaded pink, Cluster II in green and cluster III in violet.