Antimicrobial resistance and clonal evolution of Streptococcus pneumoniae serotype 19A in Russia during 2002-2013

Abstract

After the introduction of the conjugated 7-valent pneumococcal vaccine (PCV7) the incidence of infections, caused by non-vaccine serotypes of S. pneumoniae, especially by 19А serotype, significantly increased. But in few countries similar phenomenon was observed before the vaccine introduction. In the present study we evaluated retrospective collection of non-invasive S. pneumonia strains of 19А-serotypes (n=49), isolated in Russia during 2002-2013. Majority (80%) of isolates were represented by four global clonal complexes: СС156, СС230, СС320, and СС663. During 2010-2013 isolates of 19А serotype were mainly represented by СС230 and СС320 (70%), replacing previously predominant СС156 and СС663. All CC156, CC320 and CC663 isolates demonstrated penicillin MIC of ≥1 mg/l, at the same time CC230 isolates had lower penicillin MICs and were fully susceptible to amoxicillin and ceftriaxone. This finding suggests that susceptibility to beta-lactams in pneumococci of 19А serotype is clone-associated.

Keywords

• streptococcus pneumoniae
• mlst
• antimicrobial resistance
• pili