Figure 2

Phylogenetic trees for Shigella flexneri isolates. The phylogenetic trees are constructed with the MLVA profiles using an MST algorithm for (A) 242 isolates and for (B) 144 isolates from eight outbreaks. (A) Six clusters, each includes genotypes differing at eight loci or fewer among the 36 loci with the closest one, are designated and marked by different colors. The isolates in subclusters C4b and C4c defined by clustering of PFGE patterns are marked in grey. The singletons and the minor serotypes or subserotypes within a cluster are marked. (B) Outbreaks are indicated by different colors. Distances between outbreaks are numbered. A distance of one locus between two MLVA types is indicated by a thick line, a distance of two loci by a thin blue line, and a distance of three loci by a red broken line. Distances of four loci or greater are marked by a blue broken line. Distances between two genotypes differing at 5 or more loci are numbered. The area of the circle is proportional to the number of isolates belonging to the MLVA type.