Evolving genomic landscape of pediatric pneumococcus in two Canadian urban centers following conjugate vaccination

Background and aimPneumococcal conjugate vaccines (PCVs) have significantly reduced pediatric invasive pneumococcal disease (IPD). However, vaccine escape variants, the emergence of non-vaccine serotypes (NVTs), and antimicrobial resistance (AMR) remain ongoing concerns. We aimed to characterize lon...

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Main Authors: Sarah Teatero, Allison McGeer, Agron Plevneshi, Leah J. Ricketson, James D. Kellner, Nahuel Fittipaldi
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-08-01
Series:Frontiers in Microbiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2025.1642658/full
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author Sarah Teatero
Allison McGeer
Allison McGeer
Agron Plevneshi
Leah J. Ricketson
James D. Kellner
James D. Kellner
James D. Kellner
James D. Kellner
James D. Kellner
Nahuel Fittipaldi
Nahuel Fittipaldi
author_facet Sarah Teatero
Allison McGeer
Allison McGeer
Agron Plevneshi
Leah J. Ricketson
James D. Kellner
James D. Kellner
James D. Kellner
James D. Kellner
James D. Kellner
Nahuel Fittipaldi
Nahuel Fittipaldi
author_sort Sarah Teatero
collection DOAJ
description Background and aimPneumococcal conjugate vaccines (PCVs) have significantly reduced pediatric invasive pneumococcal disease (IPD). However, vaccine escape variants, the emergence of non-vaccine serotypes (NVTs), and antimicrobial resistance (AMR) remain ongoing concerns. We aimed to characterize long-term trends in serotype distribution, lineage composition, and AMR patterns among pediatric IPD cases following PCV introduction in two major Canadian urban centers: Calgary, Alberta, and Toronto, Ontario.MethodsWe combined whole-genome sequencing with epidemiologic data from 818 pediatric IPD isolates collected through population-based, active surveillance in Calgary (1998–2016) and Toronto (2009–2016). Phylogenetic analyses, serotype characterization, and AMR profiling were performed to assess temporal trends across three vaccine eras.ResultsPCV implementation reduced vaccine type serotypes but was followed by expansion of NVTs, including serotypes 22F, 33F, and 15B, with regional differences in prevalence. Serotypes 19A and 3 persisted despite PCV13 inclusion. Several pre-vaccine-associated lineages re-emerged under NVT capsules, indicating capsular switching. Macrolide resistance increased in Calgary (7.4–29.3%), distributed across multiple lineages; penicillin resistance remained infrequent.ConclusionOur findings highlight sustained pneumococcal adaptation through serotype replacement, vaccine escape, and AMR dissemination. Ongoing genomic surveillance is essential to monitor these trends and inform vaccination policies.
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spelling doaj-art-54ef675848964b5890bf6b1e87eccff22025-08-20T03:06:58ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2025-08-011610.3389/fmicb.2025.16426581642658Evolving genomic landscape of pediatric pneumococcus in two Canadian urban centers following conjugate vaccinationSarah Teatero0Allison McGeer1Allison McGeer2Agron Plevneshi3Leah J. Ricketson4James D. Kellner5James D. Kellner6James D. Kellner7James D. Kellner8James D. Kellner9Nahuel Fittipaldi10Nahuel Fittipaldi11Public Health Ontario, Toronto, ON, CanadaDepartment of Microbiology, Sinai Health System, Toronto, ON, CanadaDepartment of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, CanadaDepartment of Microbiology, Sinai Health System, Toronto, ON, CanadaDepartment of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB, CanadaDepartment of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB, CanadaAlberta Children's Hospital Research Institute, Calgary, AB, CanadaDepartment of Community Health Sciences, University of Calgary, Calgary, AB, CanadaDepartment of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, AB, CanadaAlberta Health Services, Calgary, AB, CanadaPublic Health Ontario, Toronto, ON, CanadaGREMIP and CRIPA, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, CanadaBackground and aimPneumococcal conjugate vaccines (PCVs) have significantly reduced pediatric invasive pneumococcal disease (IPD). However, vaccine escape variants, the emergence of non-vaccine serotypes (NVTs), and antimicrobial resistance (AMR) remain ongoing concerns. We aimed to characterize long-term trends in serotype distribution, lineage composition, and AMR patterns among pediatric IPD cases following PCV introduction in two major Canadian urban centers: Calgary, Alberta, and Toronto, Ontario.MethodsWe combined whole-genome sequencing with epidemiologic data from 818 pediatric IPD isolates collected through population-based, active surveillance in Calgary (1998–2016) and Toronto (2009–2016). Phylogenetic analyses, serotype characterization, and AMR profiling were performed to assess temporal trends across three vaccine eras.ResultsPCV implementation reduced vaccine type serotypes but was followed by expansion of NVTs, including serotypes 22F, 33F, and 15B, with regional differences in prevalence. Serotypes 19A and 3 persisted despite PCV13 inclusion. Several pre-vaccine-associated lineages re-emerged under NVT capsules, indicating capsular switching. Macrolide resistance increased in Calgary (7.4–29.3%), distributed across multiple lineages; penicillin resistance remained infrequent.ConclusionOur findings highlight sustained pneumococcal adaptation through serotype replacement, vaccine escape, and AMR dissemination. Ongoing genomic surveillance is essential to monitor these trends and inform vaccination policies.https://www.frontiersin.org/articles/10.3389/fmicb.2025.1642658/fullStreptococcus pneumoniaepneumococcal conjugate vaccine (PCV)serotype replacementantimicrobial resistancewhole-genome sequencinggenomic epidemiology
spellingShingle Sarah Teatero
Allison McGeer
Allison McGeer
Agron Plevneshi
Leah J. Ricketson
James D. Kellner
James D. Kellner
James D. Kellner
James D. Kellner
James D. Kellner
Nahuel Fittipaldi
Nahuel Fittipaldi
Evolving genomic landscape of pediatric pneumococcus in two Canadian urban centers following conjugate vaccination
Frontiers in Microbiology
Streptococcus pneumoniae
pneumococcal conjugate vaccine (PCV)
serotype replacement
antimicrobial resistance
whole-genome sequencing
genomic epidemiology
title Evolving genomic landscape of pediatric pneumococcus in two Canadian urban centers following conjugate vaccination
title_full Evolving genomic landscape of pediatric pneumococcus in two Canadian urban centers following conjugate vaccination
title_fullStr Evolving genomic landscape of pediatric pneumococcus in two Canadian urban centers following conjugate vaccination
title_full_unstemmed Evolving genomic landscape of pediatric pneumococcus in two Canadian urban centers following conjugate vaccination
title_short Evolving genomic landscape of pediatric pneumococcus in two Canadian urban centers following conjugate vaccination
title_sort evolving genomic landscape of pediatric pneumococcus in two canadian urban centers following conjugate vaccination
topic Streptococcus pneumoniae
pneumococcal conjugate vaccine (PCV)
serotype replacement
antimicrobial resistance
whole-genome sequencing
genomic epidemiology
url https://www.frontiersin.org/articles/10.3389/fmicb.2025.1642658/full
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