Instituto de Microbiologia, Faculdade Medicina Lisboa, Av. Prof. Egas Moniz, PT 1649-028, Lisbon, Portugal.
J Clin Microbiol. 2011 Aug;49(8):2911-8. doi: 10.1128/JCM.00271-11. Epub 2011 Jun 22.
We analyzed 212 group B streptococci (GBS) from newborns with invasive infections in the area of Barcelona, Spain, between 1992 and 2009, with the aim of documenting changes in the prevalences of serotypes, antimicrobial resistance, and genetic lineages and evaluating their associations with either early-onset disease (EOD) or late-onset disease (LOD). Serotypes III (n = 118) and Ia (n = 47) together accounted for nearly 78% of the isolates. All isolates carried an alpha or alpha-like protein gene, and specific associations between genes and serotypes, such as serotype Ib and bca, serotype II and bca, serotype III and rib, and serotype V and alp3, reflected the presence of particular genetic lineages. Macrolide resistance (14.2%) was significantly associated with serotype V. Pulsed-field gel electrophoresis (PFGE) clustering was an excellent predictor of serotype and antibiotic resistance. The combination of PFGE and multilocus sequence typing revealed a large number of genetically distinct lineages. Still, specific lineages were dominant in our collection, particularly the serotype III/ST17/rib lineage, which had enhanced potential to cause LOD. Serotype Ia was concentrated in a single PFGE cluster composed of two genetic lineages: ST23/eps and ST24/bca. The ST24/bca sublineage of serotype Ia, which is found infrequently elsewhere, may be emerging as an important cause of neonatal invasive infections in the Mediterranean region. In spite of the introduction of prophylaxis, resulting in a pronounced decline in the frequency of EOD, the study revealed a remarkably stable clonal structure of GBS causing neonatal infections in Barcelona over a period of 18 years.
我们分析了 1992 年至 2009 年期间在西班牙巴塞罗那地区发生侵袭性感染的 212 株 B 群链球菌（GBS），旨在记录血清型、抗生素耐药性和遗传谱系的流行率变化，并评估其与早发型疾病（EOD）或晚发型疾病（LOD）的关系。血清型 III（n=118）和 Ia（n=47）合计占分离株的近 78%。所有分离株均携带 alpha 或 alpha 样蛋白基因，基因与血清型之间的特定关联，如 Ib 和 bca 血清型、II 型和 bca 血清型、III 型和 rib 血清型以及 V 型和 alp3 血清型，反映了特定遗传谱系的存在。大环内酯类耐药（14.2%）与血清型 V 显著相关。脉冲场凝胶电泳（PFGE）聚类是血清型和抗生素耐药性的良好预测因子。PFGE 和多位点序列分型的组合揭示了大量遗传上不同的谱系。尽管如此，特定的谱系在我们的收集物中占主导地位，特别是血清型 III/ST17/rib 谱系，其引起 LOD 的潜力增强。血清型 Ia 集中在由两个遗传谱系组成的单个 PFGE 簇中：ST23/eps 和 ST24/bca。血清型 Ia 的 ST24/bca 亚谱系在其他地方很少见，可能正在成为地中海地区新生儿侵袭性感染的重要原因。尽管采用了预防措施，导致 EOD 的频率明显下降，但研究显示，在 18 年的时间里，导致巴塞罗那新生儿感染的 GBS 克隆结构非常稳定。
