Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, UK.
Present address: Parasites and Microbes, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton CB10 1SA, UK.
Microb Genom. 2022 Mar;8(3). doi: 10.1099/mgen.0.000783.
Cases of invasive group B streptococcal infection in the adult UK population have steadily increased over recent years, with the most common serotypes being V, III and Ia, but less is known of the genetic background of these strains. We have carried out in-depth analysis of the whole-genome sequences of 193 clinically important group B (GBS) isolates (184 were from invasive infection, 8 were from non-invasive infection and 1 had no information on isolation site) isolated from adults and submitted to the National Reference Laboratory at the UK Health Security Agency between January 2014 and December 2015. We have determined that capsular serotypes III (26.9%), Ia (26.4%) and V (15.0%) were most commonly identified, with slight differences in gender and age distribution. Most isolates (=182) grouped to five clonal complexes (CCs), CC1, CC8/CC10, CC17, CC19 and CC23, with common associations between specific serotypes and virulence genes. Additionally, we have identified large recombination events mediating potential capsular switching events between sequence type (ST)1 serotype V and serotypes Ib (=2 isolates), II (=2 isolates) and VI (=2 isolates); between ST19 serotype III and serotype V (=5 isolates); and between CC17 serotype III and serotype IV (=1 isolate). The high genetic diversity of disease-causing isolates and multiple recombination events reported in this study highlight the need for routine surveillance of the circulating disease-causing GBS strains. This information is crucial to better understand the global spread of GBS serotypes and genotypes, and will form the baseline information for any future GBS vaccine research in the UK and worldwide.
近年来，英国成年人群中侵袭性 B 群链球菌感染病例稳步增加，最常见的血清型为 V、III 和 Ia，但对这些菌株的遗传背景了解较少。我们对 193 株来自成人并于 2014 年 1 月至 2015 年 12 月期间提交给英国卫生安全局国家参考实验室的临床重要性 B 群（GBS）分离株（184 株来自侵袭性感染，8 株来自非侵袭性感染，1 株无分离部位信息）的全基因组序列进行了深入分析。我们确定了荚膜血清型 III（26.9%）、Ia（26.4%）和 V（15.0%）最常见，性别和年龄分布略有差异。大多数分离株（=182）分为五个克隆复合体（CC），CC1、CC8/CC10、CC17、CC19 和 CC23，特定血清型与毒力基因之间存在常见关联。此外，我们还发现了介导 ST1 血清型 V 与 Ib（=2 株）、II（=2 株）和 VI（=2 株）之间潜在荚膜转换事件的大型重组事件；ST19 血清型 III 与血清型 V（=5 株）之间；以及 CC17 血清型 III 与 IV（=1 株）之间。本研究报告的致病分离株遗传多样性高且发生多次重组事件，这突出表明需要对循环致病 GBS 菌株进行常规监测。该信息对于更好地了解 GBS 血清型和基因型在全球的传播至关重要，也将为英国和全球未来任何 GBS 疫苗研究提供基线信息。
