FIG. 3.

Phylogenetic representation of 9-MLVA. Computed base pair lengths for all nine loci were reported in the START spreadsheet from which a UPGMA (unweighted pair-group method with arithmetic averages) tree was inferred. The 8-MLVA was central to determining three major phylogenetic patterns, corresponding to the genotypes 1, 12, and 3. The progressive hierarchical addition of the high-resolution pXO2-A assay results, maximizing the phylogenetic accuracy, subdivided the 23 isolates of genotype 3 into eight unique subtypes. Both genotypes 1 and 12 were divided into two subtypes. Allelic profiles are shown along with the isolate names. The pXO1- or pXO2-deficient strains were not included due to incomplete 8-MLVA patterns. The linkage distance attempts to measure the detected association between alleles at different loci (16).