Population structure of hyperinvasive serotype 12F, clonal complex 218 Streptococcus pneumoniae revealed by multilocus boxB sequence typing

► Hyperinvasive pneumococci not targeted by conjugate vaccines should be monitored. ► We developed a minisatellite sequence typing method to study 12F, CC218 pneumococci. ► Hidden population structure was revealed among these hyperinvasive pneumococci.