Among Rochester NY children, a dramatic increase in nasopharyngeal (NP) colonization by non-vaccine pneumococcal serotypes 35B and 15A occurred during years 2010–2015, after introduction of 13-valent pneumococcal conjugate vaccine (PCV13). In our population, serotype 35B strains colonized in the nasopharynx (NP) but infrequently caused acute otitis media (AOM) whereas serotype 15A strains displayed virulence, evidenced by causing AOM. To explain the virulence difference, virulence genes expression between 35B and 15A, as well as the host’s immune response during asymptomatic colonization were analyzed. We investigated differences in regulation of 19 virulence genes for differences in virulence using RT-PCR in 20 35B and 14 15A strains and measured gene expression of 9 host innate cytokines in the NP to assess the mucosal inflammatory response during asymptomatic colonization. Comparing 35B versus 15A strains, genes for competence ComA and RrgC were upregulated; capsular (Cps2D) and virulence genes (PfbA, PcpA and PhtE) were downregulated among 35B strains. PavB, LytA, LytB, NanA, CiaR, PhtD, LuxS, PspA and pneumolysin (Ply) showed no difference. IL17 and IL23 gene expression were > tenfold higher during 35B compared to 15A strain asymptomatic colonization. Only IL23 showed significant difference. In the first 5 years after introduction of PCV13, serotype 35B strains emerged as asymptomatic colonizers and 15A strains emerged to cause AOM in young children. Various genes (PfbA, PcpA, Cps2D and PhtE) among tested in this analysis were downregulated in 35B whereas ComA and RrgC were significantly upregulated. For the host’s cytokine response, IL23 proinflammatory response which is essential for the differentiation of Th17 lymphocytes in the NP of children with 35B strains was significantly higher than the response to 15A during asymptomatic colonization.

在纽约州罗切斯特儿童中，在引入 13 价肺炎球菌结合疫苗 (PCV13) 后，2010-2015 年期间非疫苗肺炎球菌血清型 35B 和 15A 的鼻咽 (NP) 定植显着增加。在我们的人群中，血清型 35B 菌株定植在鼻咽 (NP) 中，但很少引起急性中耳炎 (AOM)，而血清型 15A 菌株显示出毒力，通过引起 AOM 来证明。为了解释毒力差异，分析了 35B 和 15A 之间的毒力基因表达，以及宿主在无症状定植期间的免疫反应。我们使用 RT-PCR 在 20 35B 和 14 15A 菌株中研究了 19 种毒力基因调控的差异，并测量了 NP 中 9 种宿主先天细胞因子的基因表达，以评估无症状定植期间的粘膜炎症反应。比较 35B 与 15A 菌株，能力 ComA 和 RrgC 的基因被上调；荚膜 (Cps2D) 和毒力基因 (PfbA、PcpA 和 PhtE) 在 35B 菌株中下调。PavB、LytA、LytB、NanA、CiaR、PhtD、LuxS、PspA 和肺炎球菌溶血素 (Ply) 没有显示出差异。与 15A 菌株无症状定植相比，IL17 和 IL23 基因表达在 35B 期间高出 10 倍以上。只有IL23表现出显着差异。在引入 PCV13 后的前 5 年中，血清型 35B 菌株作为无症状定植者出现，15A 菌株出现在幼儿中引起 AOM。在该分析中测试的各种基因（PfbA、PcpA、Cps2D 和 PhtE）在 35B 中下调，而 ComA 和 RrgC 显着上调。对于宿主的细胞因子反应，对于 35B 株儿童 NP 中 Th17 淋巴细胞分化必不可少的 IL23 促炎反应显着高于无症状定植期间对 15A 的反应。