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A helicase-containing module defines a family of pCD630-like plasmids in Clostridium difficile
Wiep Klaas Smits1, J Scott Weese2, Adam P Roberts3
1Department of Medical Microbiology, Leiden University Medical Center, PO Box 9600, 2300RC, Leiden, The Netherlands; Netherlands Centre for One Health, The Netherlands.
Abstract:
Clostridium difficile is a Gram-positive and sporulating enteropathogen that is a major cause of healthcare-associated infections. Even though a large number of genomes of this species have been sequenced, only a few plasmids have been described in the literature. Here, we use a combination of in silico analyses and laboratory experiments to show that plasmids are common in C. difficile. We focus on a group of plasmids that share similarity with the plasmid pCD630, from the reference strain 630. The family of pCD630-like plasmids is defined by the presence of a conserved putative helicase that is likely part of the plasmid replicon. This replicon is compatible with at least some other C. difficile replicons, as strains can carry pCD630-like plasmids in addition to other plasmids. We find two distinct sub-groups of pCD630-like plasmids that differ in size and accessory modules. This study is the first to describe a family of plasmids in C. difficile.
Insights
Plasmids are common in Clostridium difficile, a major cause of healthcare-associated infections. This study identifies a novel family of pCD630-like plasmids, revealing two distinct subgroups within this important bacterial species.
Area of Science:
- Microbiology
- Genomics
- Molecular Biology
Background:
- Clostridium difficile is a significant Gram-positive enteropathogen responsible for healthcare-associated infections.
- Despite extensive genomic sequencing of C. difficile, plasmids remain poorly characterized.
- Few plasmids have been previously described in C. difficile literature.
Purpose of the Study:
- To investigate the prevalence and diversity of plasmids in Clostridium difficile.
- To characterize a specific family of plasmids related to pCD630.
- To identify novel plasmid replicons and their compatibility within C. difficile strains.
Main Methods:
- In silico genomic analyses.
- Laboratory experiments for plasmid characterization.
- Comparative analysis of plasmid sequences.
Main Results:
- Plasmids are common in Clostridium difficile.
- A novel family of pCD630-like plasmids was identified, characterized by a conserved putative helicase.
- Two distinct subgroups of pCD630-like plasmids were discovered, differing in size and accessory modules.
- The identified replicon is compatible with other C. difficile replicons, allowing co-existence.
Conclusions:
- This study provides the first description of a plasmid family in Clostridium difficile.
- The findings expand our understanding of C. difficile plasmid biology and mobile genetic elements.
- The characterization of pCD630-like plasmids offers new insights into C. difficile genomics and potential virulence factors.
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