Genetic relatedness of Streptococcus dysgalactiae isolates causing recurrent bacteraemia
Senneby, Erik LU ; Hallström, Björn LU and Rasmussen, Magnus LU
(2021)
In Journal of Medical Microbiology
70(3).
- Abstract
Introduction.Streptococcus dysgalactiae subspecies equisimilis (SDSE) is becoming increasingly recognized as an important human pathogen. Recurrent bacteremia with SDSE has been described previously.Aim. The aims of the study were to establish the genetic relatedness of SDSE isolates with emm-type stG643 that had caused recurrent bacteraemia in three patients and to search for signs of horizontal gene transfer of the emm gene in a collection of SDSE stG643 genomes.Hypothesis. Recurring SDSE bacteremia is caused by the same clone in one patient.Methodology. Whole genome sequencing of 22 clinical SDSE stG643 isolates was performed, including three paired blood culture isolates and sixteen isolates from various sites. All assemblies were... (More)
Introduction.Streptococcus dysgalactiae subspecies equisimilis (SDSE) is becoming increasingly recognized as an important human pathogen. Recurrent bacteremia with SDSE has been described previously.Aim. The aims of the study were to establish the genetic relatedness of SDSE isolates with emm-type stG643 that had caused recurrent bacteraemia in three patients and to search for signs of horizontal gene transfer of the emm gene in a collection of SDSE stG643 genomes.Hypothesis. Recurring SDSE bacteremia is caused by the same clone in one patient.Methodology. Whole genome sequencing of 22 clinical SDSE stG643 isolates was performed, including three paired blood culture isolates and sixteen isolates from various sites. All assemblies were aligned to a reference assembly and SNPs were extracted. A total of 53 SDSE genomes were downloaded from GenBank. Two phylogenetic trees, including all 75 SDSE isolates, were created. One tree was based on the emm gene only and one tree was based on all variable positions in the genomes.Results. The genomes from the three pairs of SDSE isolates showed high sequence similarity (1-17 SNPs difference between the pairs), whereas the median SNP difference between the 22 isolates in our collection was 1694 (range 1-11257). The paired isolates were retrieved with 7-53 months between episodes. The 22 SDSE isolates from our collection formed a cluster in the phylogenetic tree based on the emm gene, while they were more scattered in the tree based on all variable positions.Conclusions. Our results show that the paired isolates were of the same clonal origin, which in turn supports carriage between bacteraemia episodes. The phylogenetic analysis indicates that horizontal gene transfer of the emm-gene between some of the SDSE isolates has occurred.
(Less)
- author
- Senneby, Erik
LU
; Hallström, Björn
LU
and Rasmussen, Magnus
LU
- organization
- publishing date
- 2021
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- emmgene, genetic relatedness, Streptococcus dysgalactiae, whole genome sequencing
- in
- Journal of Medical Microbiology
- volume
- 70
- issue
- 3
- publisher
- Lippincott Williams & Wilkins
- external identifiers
-
- scopus:85103682121
- pmid:33616518
- ISSN
- 0022-2615
- DOI
- 10.1099/jmm.0.001330
- language
- English
- LU publication?
- yes
- id
- de3592c2-ce99-4e5b-a2f4-f383e7e924fa
- date added to LUP
- 2021-04-13 09:45:38
- date last changed
- 2024-12-01 04:07:15
@article{de3592c2-ce99-4e5b-a2f4-f383e7e924fa,
abstract = {{<p>Introduction.Streptococcus dysgalactiae subspecies equisimilis (SDSE) is becoming increasingly recognized as an important human pathogen. Recurrent bacteremia with SDSE has been described previously.Aim. The aims of the study were to establish the genetic relatedness of SDSE isolates with emm-type stG643 that had caused recurrent bacteraemia in three patients and to search for signs of horizontal gene transfer of the emm gene in a collection of SDSE stG643 genomes.Hypothesis. Recurring SDSE bacteremia is caused by the same clone in one patient.Methodology. Whole genome sequencing of 22 clinical SDSE stG643 isolates was performed, including three paired blood culture isolates and sixteen isolates from various sites. All assemblies were aligned to a reference assembly and SNPs were extracted. A total of 53 SDSE genomes were downloaded from GenBank. Two phylogenetic trees, including all 75 SDSE isolates, were created. One tree was based on the emm gene only and one tree was based on all variable positions in the genomes.Results. The genomes from the three pairs of SDSE isolates showed high sequence similarity (1-17 SNPs difference between the pairs), whereas the median SNP difference between the 22 isolates in our collection was 1694 (range 1-11257). The paired isolates were retrieved with 7-53 months between episodes. The 22 SDSE isolates from our collection formed a cluster in the phylogenetic tree based on the emm gene, while they were more scattered in the tree based on all variable positions.Conclusions. Our results show that the paired isolates were of the same clonal origin, which in turn supports carriage between bacteraemia episodes. The phylogenetic analysis indicates that horizontal gene transfer of the emm-gene between some of the SDSE isolates has occurred.</p>}},
author = {{Senneby, Erik and Hallström, Björn and Rasmussen, Magnus}},
issn = {{0022-2615}},
keywords = {{emmgene; genetic relatedness; Streptococcus dysgalactiae; whole genome sequencing}},
language = {{eng}},
number = {{3}},
publisher = {{Lippincott Williams & Wilkins}},
series = {{Journal of Medical Microbiology}},
title = {{Genetic relatedness of Streptococcus dysgalactiae isolates causing recurrent bacteraemia}},
url = {{http://dx.doi.org/10.1099/jmm.0.001330}},
doi = {{10.1099/jmm.0.001330}},
volume = {{70}},
year = {{2021}},
}