Fig. 3.

Minimum spanning tree of the results obtained by MLVA using a categorical coefficient. Each node represents a different MLVA type, with shading of nodes indicating the numbers of isolates of that particular type, as shown in the key. Thick dark lines separate types differing by a single locus, while thin continuous lines connect double locus variants. Faint lines represent types differing by ⩾3 loci. Shading around nodes demonstrates partitioning of isolates differing by only one locus, and indicates designated clonal complexes. Sequence types (ST) and BOX groups are also labelled.