Shigella sonnei utilises colicins during inter- bacterial competition
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The mammalian colon is one of the most densely populated habitats currently recognised, with 1011–1013 commensal bacteria per gram of colonic contents. Enteric pathogens must compete with the resident intestinal microbiota to cause infection. Among these enteric pathogens are Shigella species which cause approximately 125 million infections annually, of which over 90 % are caused by Shigella flexneri and Shigella sonnei. Shigella sonnei was previously reported to use a Type VI Secretion System (T6SS) to outcompete E. coli and S. flexneri in in vitro and in vivo experiments. S. sonnei strains have also been reported to harbour colicinogenic plasmids, which are an alternative anti-bacterial mechanism that could provide a competitive advantage against the intestinal microbiota. We sought to determine the contribution of both T6SS and colicins to the anti-bacterial killing activity of S. sonnei. We reveal that whilst the T6SS operon is present in S. sonnei, there is evidence of functional degradation of the system through SNPs, indels and IS within key components of the system. We created strains with synthetically inducible T6SS operons but were still unable to demonstrate anti-bacterial activity of the T6SS. We demonstrate that the anti-bacterial activity observed in our in vitro assays was due to colicin activity. We show that S. sonnei no longer displayed anti-bacterial activity against bacteria that were resistant to colicins, and removal of the colicin plasmid from S. sonnei abrogated anti-bacterial activity of S. sonnei. We propose that the anti-bacterial activity demonstrated by colicins may be sufficient for niche competition by S. sonnei within the gastrointestinal environment.
Date Issued
2024-02-20
Date Acceptance
2024-01-25
Citation
Microbiology (United Kingdom), 2024, 170 (2)
ISSN
1350-0872
Publisher
Microbiology Society
Journal / Book Title
Microbiology (United Kingdom)
Volume
170
Issue
2
Copyright Statement
© 2024 The Authors 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.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/38376387
Subjects
anti- bacterial activity
BURDEN
colicins
DIVERSITY
INFECTIONS
Interbacterial competition
Life Sciences & Biomedicine
Microbiology
polymicrobial
PRODUCE
RESISTANCE
Science & Technology
Shigella
STRAINS
T6SS
VI SECRETION SYSTEM
Publication Status
Published
Coverage Spatial
England
Article Number
001434
Date Publish Online
2024-02-20