A Clustering analysis of genotyping data. The 67 genotypes are numbered from 1 to 67 (left-most column). The origin of the strains (when known) is indicated; ND, unknown. "Cluster" refers to the clustering and "group" refers to the genotype (GT) number based upon MLVA8 as proposed in . Genotypes with no group assigned are usually minor variations of known, neighbouring groups. A number of reference strains are indicated in ().