Infect Genet Evol. 2016 Apr 9. pii: S1567-1348(16)30133-2. doi: 10.1016/j.meegid.2016.04.007. [Epub ahead of print]

Population structure and drug resistance patterns of emerging non-PCV-13 Streptococcus pneumoniaeserotypes 22F, 15A, and 8 isolated from adults in Ontario, Canada.

Duvvuri VR1, Deng X2, Teatero S3, Memari N4, Athey T5, Fittipaldi N6, Gubbay JB7.

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Abstract

The introduction of pneumococcal conjugate vaccines has led to the emergence of non-vaccine serotypes, which contributed to invasive pneumococcal disease in Canada and worldwide. A significant increase in the prevalence of non-13-valent pneumococcal conjugate vaccine (PCV-13)-included serotypes 22F, 15A, and 8 was observed from 2009 to 2013 in Ontario (all p values<0.01). In this study, whole genome sequencing was conducted on the 25 isolates of serotype 22F, seven of 15A and 10 of 8 to investigate the population structure and antibiotic resistance. All seven serotype 15A isolates were found to be multidrug resistant. From whole genome analysis, we observed recombination events among serotypes 22F, 15A and 8 populations. Serotype 22F (ST433) has emerged into two sub-populations, with 28% (7/25) exhibiting recombination events, and five also acquiring macrolide resistance as a result of recombination. This study enhances the knowledge on the molecular evolution of emerging non-PCV-13 vaccine serotype 22F, including acquisition of resistance genes through recombination events. It underpins the importance of whole genome sequencing in studying Streptococcus pneumoniae population structures and dynamics, and its utility in molecular surveillance.

Copyright © 2015. Published by Elsevier B.V.

KEYWORDS:

Antimicrobial resistance; Invasive pneumococcal disease; Non-PCV-13 serotypes; Streptococcus pneumoniae; Whole-genome sequencing

PMID: 27071529 [PubMed - as supplied by publisher]