IAME, UMR 1137, INSERM, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
Service de Microbiologie, Centre National de Référence Escherichia coli, Hôpital Robert-Debré, AP-HP, 48 boulevard Sérurier, 75019, Paris, France.
BMC Microbiol. 2019 Jan 17;19(1):17. doi: 10.1186/s12866-018-1376-4.
To describe the temporal dynamics, molecular characterization, clinical and ex vivo virulence of emerging O1:K1 neonatal meningitis Escherichia coli (NMEC) strains of Sequence Type complex (STc) 95 in France. The national reference center collected NMEC strains and performed whole genome sequencing (WGS) of O1:K1 STc95 NMEC strains for phylogenetic and virulence genes content analysis. Data on the clinical and biological features of patients were also collected. Ex vivo virulence was assessed using the Dictyostelium discoideum amoeba model.
Among 250 NMEC strains collected between 1998 and 2015, 38 belonged to O1:K1 STc95. This clonal complex was the most frequently collected after 2004, representing up to 25% of NMEC strains in France. Phylogenetic analysis demonstrated that most (74%) belonged to a cluster designated D-1, characterized by the adhesin FimH30. There is no clinical data to suggest that this cluster is more pathogenic than its counterparts, although it is highly predominant and harbors a large repertoire of extraintestinal virulence factors, including a pS88-like plasmid. Ex vivo virulence model showed that this cluster was generally less virulent than STc95 reference strains of O45:H7 and O18:H7 serotypes. However, the model showed differences between several subclones, although they harbor the same known virulence determinants.
The emerging clonal group O1:K1 STc95 of NMEC strains is mainly composed of a cluster with many virulence factors but of only moderate virulence. Whether its emergence is due to its ability to colonize the gut thanks to FimH30 or pS88-like plasmid remains to be determined.
描述法国新兴 O1:K1 新生儿脑膜炎大肠杆菌（NMEC）序列型复合物（STc）95 菌株的时间动态、分子特征、临床和离体毒力。国家参考中心收集 NMEC 菌株，并对 O1:K1 STc95 NMEC 菌株进行全基因组测序（WGS），以进行系统发育和毒力基因含量分析。还收集了有关患者临床和生物学特征的数据。使用变形虫 Dictyostelium discoideum 模型评估离体毒力。
在 1998 年至 2015 年间收集的 250 株 NMEC 菌株中，有 38 株属于 O1:K1 STc95。该克隆复合体在 2004 年后最常被采集，占法国 NMEC 菌株的 25%。系统发育分析表明，大多数（74%）属于一个名为 D-1 的聚类，其特征是黏附素 FimH30。没有临床数据表明该聚类比其对应物更具致病性，尽管它高度占主导地位且具有大量肠外毒力因子，包括 pS88 样质粒。离体毒力模型表明，该聚类通常比 O45:H7 和 O18:H7 血清型的 STc95 参考菌株的毒力低。然而，该模型显示了几个亚克隆之间的差异，尽管它们具有相同的已知毒力决定因素。
NMEC 菌株的新兴克隆群 O1:K1 STc95 主要由一个具有许多毒力因子但毒力中等的聚类组成。其出现是否归因于其通过 FimH30 或 pS88 样质粒定植肠道的能力仍有待确定。
