Teatero Sarah, McGeer Allison, Plevneshi Agron, Ricketson Leah J, Kellner James D, Fittipaldi Nahuel
Public Health Ontario, Toronto, ON, Canada.
Department of Microbiology, Sinai Health System, Toronto, ON, Canada.
Front Microbiol. 2025 Aug 18;16:1642658. doi: 10.3389/fmicb.2025.1642658. eCollection 2025.
Pneumococcal 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.
We 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.
PCV 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.
Our 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.
肺炎球菌结合疫苗（PCV）已显著降低儿童侵袭性肺炎球菌疾病（IPD）的发病率。然而，疫苗逃逸变异株、非疫苗血清型（NVT）的出现以及抗菌药物耐药性（AMR）仍是持续存在的问题。我们旨在描述加拿大两个主要城市中心（艾伯塔省卡尔加里市和安大略省多伦多市）引入PCV后儿童IPD病例血清型分布、谱系组成和AMR模式的长期趋势。
我们将全基因组测序与来自卡尔加里市（1998 - 2016年）和多伦多市（2009 - 2016年）通过基于人群的主动监测收集的818株儿童IPD分离株的流行病学数据相结合。进行系统发育分析、血清型鉴定和AMR分析，以评估三个疫苗时代的时间趋势。
PCV的实施降低了疫苗型血清型，但随后NVT出现扩张，包括22F、33F和15B血清型，患病率存在地区差异。尽管PCV13中包含了19A和3血清型，但它们仍然存在。在NVT荚膜下，几种疫苗接种前相关谱系重新出现，表明发生了荚膜转换。卡尔加里市的大环内酯类耐药性增加（从7.4%增至29.3%），分布于多个谱系；青霉素耐药性仍然少见。
我们的研究结果突出了肺炎球菌通过血清型替代、疫苗逃逸和AMR传播持续发生适应性变化。持续的基因组监测对于监测这些趋势并为疫苗接种政策提供信息至关重要。
