How did some Enterococcus faecium become hospital pathogens?
Comparative pangenomes split E. faecium into a mixed-source subclade I and a human-only subclade II with larger genomes packed with resistance, virulence, bacteriocin, and mobile genes likely gained by HGT.
Source
Comparative pangenome analysis of Enterococcus faecium and Enterococcus lactis provides new insights into the adaptive evolution by horizontal gene acquisitions
Study at a glance
- Design
- Computational / modelling — Comparative pangenome analysis of dereplicated E. faecium and E. lactis genomes
- N
- All available dereplicated genomes of the two species (counts in full text tables)
- Population
- Enterococcus faecium and Enterococcus lactis genomes from diverse isolation sources
- Outcome
- Subclade structure and enrichment of resistance/virulence/mobile genes
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
They analyzed all available dereplicated genomes of E. faecium and closely related E. lactis, comparing phylogeny, genome size/gene content, and resistance/virulence gene histories.
What they found
Subclade II was exclusively human-derived, larger, and richer in resistance/virulence/mobile elements; phylogenetic patterns support horizontal acquisition tied to antibiotic pressure. E. lactis did not cluster by isolation source.
The limits
What it doesn't show
Genome catalogs do not measure in-host virulence experimentally or prove causality for every gene’s clinical effect.
Key terms
- Pangenome
- Union of genes across all genomes of a species.
- E. faecium
- Enterococcus species that can be commensal or nosocomial pathogen.
- E. lactis
- Closely related Enterococcus often linked to foods/commensal niches.
- Subclade II
- More recent human-restricted E. faecium lineage in this study.
- Horizontal gene transfer
- Gene acquisition between strains other than vertical inheritance.
- Mobile element
- DNA that can move within/between genomes (e.g., plasmids, IS).
Flashcards
Research intelligence for this paper
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Quiz yourself
Subclade II isolation sources:
Common questions
How many E. faecium subclades?
Two: mixed-source I and human-only II.
What is special about subclade II?
Larger genomes; more resistance/virulence/bacteriocin/mobile genes.
Proposed acquisition route?
Horizontal gene transfer under antibiotic pressure.
E. lactis clustering?
No clear clustering by isolation source.
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