A multiple drug-resistant Streptococcus pneumoniae of serotype 15A occurring from serotype 19A by capsular switching.

Streptococcus pneumoniae is a highly recombinogenic pathogen. The ability of pneumococci to acquire and incorporate exogenous DNA is an important evolutionary mechanism for adaptation to clinical interventions such as antibiotic therapy and vaccination. Herein, using whole genome sequencing we detected a multiple drug-resistant serotype 15A pneumococcus emerged by capsular switching from serotype 19A/ST276. The dissemination of recombinant multiple drug-resistant pneumococcal clones with non-vaccine type capsule is of concern and warrants thorough monitoring of serotype and genotype structure within pneumococcal populations.