Figure 2. Phylogenetic clustering of pneumococcal strains using concatenated genomic sequences of all 11 genes.

Genomic sequence information of all the 11 gene fragments of 72 S. pneumoniae strains was used to generate the phylogenetic tree, and MrBayes program was used to generate the consensus tree as described in Methods. The clustering was viewed and edited in TreeDyn http://www.treedyn.org/. The posterior probability score of clusters at its node ranged from 0.5 to 1.0. The frequency of posterior probability score of 1.0 was 63% and only 20% of clusters showed 0.5 as the posterior probability score at their nodes. Unexpected clusters of strains, based on MLST classifications, are indicated with shaded backgrounds. A: ST-complex designation, B: serotype/serogroup designation.