FIG 1.

Serotype changes in S. pneumoniae serogroup 6 isolates from South Korea during three periods, 1996 to 2001, 2004 to 2006, and 2008 to 2009. During these periods, serogroup 6 increased from 9.7 to 17.5% (P = 0.012). While serotype 6B decreased from 4.4 to 0.9% (P = 0.016), serotypes 6A and 6D increased significantly. Putative serotype 6E isolates, most of which were classified as serotype 6B on the basis of the Quellung reaction, also increased from 1.3 to 3.3%, but the increase was not statistically significant (P = 0.146).