Fig 1.

Relatedness of spa types among adult (A) and pediatric (B) MRSA isolates according to the Based upon Repeat Pattern (BURP) algorithm. Clusters of linked spa types correspond to spa clonal complexes (spa-CCs). spa types are clustered into a spa-CC when their repeat patterns differ by no more than 4 repeats. The BURP algorithm sums up “costs” (a measure of relatedness based on the repeat pattern) to define a founder score for each spa type in a spa-CC. The founder (blue node) is the spa type with the highest founder score in its spa-CC, and the subfounder (yellow node) is the spa type with the second highest founder score. spa-CC008 has founder t008. Each node represents a spa type. The node size represents the number of clustered strains that belong to that spa type. The shading of the branches represents the costs (similarities in repeat patterns) between two spa types; the darker the branch, the lower the cost (more similar repeat patterns).