Abstract
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 Streptococcus (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 (n=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 (n=2 isolates), II (n=2 isolates) and VI (n=2 isolates); between ST19 serotype III and serotype V (n=5 isolates); and between CC17 serotype III and serotype IV (n=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.
| Original language | English |
|---|---|
| Article number | 000783 |
| Journal | Microbial Genomics |
| Volume | 8 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 15 Mar 2022 |
Bibliographical note
Funding Information: Laboratory work was funded by the UKHSA. The Fiona Elizabeth Agnew Trust (FEATURES award) and Cardiff University provided financial support to O.B.S. (including the studentship of U.B.K.). E.J. is a Rosetrees/Stoneygate 2017 Imperial College Research Fellow, funded by the Rosetrees Trust and the Stoneygate Trust. E.J. is also affiliated with the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Healthcare Associated Infections and Antimicrobial Resistance at Imperial College London, in partnership with the UKHSA, in collaboration with Imperial Healthcare Partners, the University of Cambridge and the University of Warwick.We thank colleagues for their work in maintaining laboratory surveillance through interfacing with local hospitals. We extend our sincere thanks to the efforts of hospital microbiology and surveillance staff across the country in referring specimens for laboratory surveillance. Special thanks to staff at the Reference Laboratory UKHSA, for expert assistance with DNA extraction and sequencing. This publication made use of the PubMLST website (https://pubmlst.org/) developed by Keith Jolley and colleagues [30] and sited at the University of Oxford. The development of that website was funded by the Wellcome Trust.
Open Access: This is an open-access article distributed under the terms of the Creative Commons Attribution License. This article was made open access via a Publish and Read agreement between the Microbiology Society and the corresponding author’s institution.
Publisher Copyright: © 2022 Crown Copyright.
Citation: Khan, Uzma Basit, et al. "Identifying large-scale recombination and capsular switching events in Streptococcus agalactiae strains causing disease in adults in the UK between 2014 and 2015." Microbial Genomics 8.3 (2022): 000783.
DOI: https://doi.org/10.1099/mgen.0.000783
Keywords
- MLST
- capsular serotype
- epidemiology
- group B Streptococcus
- whole-genome sequencing
