Laboratoire de Microbiologie, Hôpital Robert Debré, Service de Microbiologie, Assistance Publique des Hôpitaux de Paris, Paris, France.
J Clin Microbiol. 2013 Jun;51(6):1727-32. doi: 10.1128/JCM.03255-12. Epub 2013 Mar 20.
Maternal-fetal Escherichia coli infections, such as neonatal bacteremia and meningitis, are important causes of morbidity and mortality. From 2006 to 2010, we studied newborns and their mothers who were colonized with E. coli in a French hospital in order to document (i) the epidemiology and genetic characteristics of extended-spectrum-beta-lactamase (ESBL)-producing E. coli strains, (ii) the prevalence of associated virulence genes, (iii) the prevalence of clone sequence type 131 (ST131), and (iv) the genetic relationship among ESBL-producing strains. Among the 2,755 E. coli cultures recovered from vaginal or neonatal samples, 68 were ESBL producers (2.46%). We found a wide diversity of ESBL genes, with the majority being bla(CTX-M-14), bla(CTX-M-1), and bla(CTX-M-15), distributed among the 4 main phylogenetic groups. Genes encoding virulence factors were found in 90.7% of the isolates, with ≥ 2 virulence genes present in 76% of cases. The prevalence of ST131 among ESBL-producing E. coli isolates was 9.4% (6/64). Five of these 6 ST131 isolates possessed bla(CTX-M-15) enzymes (and also were resistant to quinolones), and one possessed bla(CTX-M-2) enzymes. Two possessed virulence genes, suggesting the presence of pathogenicity island IIJ96 (PAI IIJ96)-like domains. Pulsed-field gel electrophoresis (PFGE) revealed a high level of genomic diversity overall, except for 3 closely related isolates belonging to clonal group ST131. Repetitive PCR showed that the six ST131 isolates were closely related to ST131 control strains (>95% similarity). This study shows a high prevalence of ESBL-producing E. coli strains and clonal group ST131 in the French maternal-fetal population. These results suggest a widespread distribution of ESBL enzymes in the community and highlight the early transmission between mothers and neonates. These findings are worrisome, especially for this particularly vulnerable population.
母体-胎儿大肠杆菌感染，如新生儿菌血症和脑膜炎，是发病率和死亡率的重要原因。 2006 年至 2010 年，我们研究了法国一家医院中定植大肠杆菌的新生儿及其母亲，以记录（i）产超广谱β-内酰胺酶（ESBL）大肠杆菌菌株的流行病学和遗传特征，（ii）相关毒力基因的流行率，（iii）克隆序列型 131（ST131）的流行率，以及（iv）产 ESBL 菌株之间的遗传关系。 在从阴道或新生儿样本中回收的 2755 株大肠杆菌培养物中，有 68 株为 ESBL 产生菌（2.46％）。 我们发现 ESBL 基因种类繁多，主要为 bla（CTX-M-14），bla（CTX-M-1）和 bla（CTX-M-15），分布于 4 个主要的系统发育群中。 在 90.7％的分离株中发现了编码毒力因子的基因，76％的情况下存在≥2种毒力基因。 在产 ESBL 的大肠杆菌分离株中，ST131 的流行率为 9.4％（6/64）。 在这 6 个 ST131 分离株中，有 5 个分离株携带 bla（CTX-M-15）酶（并且也对喹诺酮类药物具有抗性），1 个分离株携带 bla（CTX-M-2）酶。 两个分离株具有毒力基因，提示存在致病性岛 IIJ96（PAI IIJ96）样结构域。 脉冲场凝胶电泳（PFGE）显示总体上具有很高的基因组多样性，除了属于克隆群 ST131 的 3 个密切相关的分离株外。 重复 PCR 显示，6 个 ST131 分离株与 ST131 对照株密切相关（> 95％相似性）。 这项研究表明，法国母婴人群中 ESBL 产生大肠杆菌菌株和克隆群 ST131 的流行率很高。 这些结果表明 ESBL 酶在社区中的广泛分布，并强调了母亲和新生儿之间的早期传播。 这些发现令人担忧，尤其是对这个特别脆弱的人群。
