Changes between the 2009 and 2011 samples within individual serotypes (a) 19A (b) 15B/C and (c) 6C amongS. pneumoniaecarriage isolates in children 3 months - 7 years from selected Massachusetts communities. Results for 2009 are shown in gray and 2011 in black. STs are shown as the proportion of isolates within each serotype, arranged by clonal complex according to eBURST analysis. The ancestral ST of each clonal complex in eBURST analysis is shown below the panel. Other indicates STs for which ancestry could not be determined by eBURST.