Figure 1.

Neighbor joining phylogeny of rgf operon alleles by multilocus sequence type (ST). The evolutionary distances between rgf operon sequences (3320 bp) for 41 strains of different STs were calculated using the p-distance method, which is represented as the number of base differences per site. The bootstrap test (1000 replicates) values are represented at the nodes. The rgfC sequence, which was classified as complete or with an 881 bp deletion, contributed to the clustering observed in the phylogeny. S = singleton.