Serotype Switch Variant of Multidrug-Resistant Streptococcus pneumoniae Sequence Type 271

We discovered 3 invasive, multidrug-resistant Streptococcus pneumoniae isolates of vaccine-refractory capsular serotype 3 that recently arose within the successful sequence type 271 complex through a serotype switch recombination event. Mapping genomic recombination sites within the serotype 3/sequence type 271 progeny revealed a 55.9-kb donated fragment that encompassed cps3, pbp1a, and additional virulence factors.

Automated summary

We identified 3 newly emerged invasive, multidrug-resistant Streptococcus pneumoniae isolates of vaccine-refractory capsular serotype 3 within the successful sequence type 271 complex, originating from a serotype switch recombination event. Mapping genomic recombination sites in the serotype 3/sequence type 271 progeny revealed a 55.9-kb donated fragment containing cps3, pbp1a, and additional virulence factors.