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Recent recombination events in the core genome are associated with adaptive evolution in Enterococcus faecium
Mark de Been1, Willem van Schaik, Lu Cheng
1Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands. m.debeen-2@umcutrecht.nl
Genome Biology and Evolution
|July 25, 2013
Summary
Recombination significantly reshapes the Enterococcus faecium genome, with gut commensal strains donating DNA to clinical isolates. This genetic exchange fuels the rise of E. faecium as a hospital pathogen.
Area of Science:
- Microbiology
- Genomics
- Evolutionary Biology
Background:
- Enterococcus faecium is a significant opportunistic pathogen with increasing clinical impact.
- Rapid acquisition of adaptive genetic elements contributes to E. faecium's success.
- Understanding the role of recombination is crucial for deciphering E. faecium's evolution.
Purpose of the Study:
- To investigate the impact of recombination on the core genome evolution of Enterococcus faecium.
- To identify the major sources and recipients of foreign DNA via recombination.
- To explore the association between recombination patterns and E. faecium's pathogenicity.
Main Methods:
- Utilized the BratNextGen algorithm to detect recombinant regions in the core genome.
- Analyzed 34 E. faecium strains, including three newly sequenced clinical isolates.
- Compared recombination patterns across different E. faecium clades and identified specific recombining regions.
Main Results:
- Recombination affects a substantial portion (0.5 million out of 1.2 million) of the E. faecium core genome.
- Clade B (human gut commensals) acts as a primary reservoir for donating DNA to Clade A (clinical isolates).
- Specific genomic regions, including the epa-like locus involved in cell wall polysaccharide biosynthesis, show preferential recombination in hospital-associated strains.
Conclusions:
- Recombination plays a pivotal role in the genomic evolution of Enterococcus faecium.
- The exchange of genetic material between commensal and pathogenic clades facilitates adaptation and virulence.
- Targeted recombination in specific regions may contribute to the emergence of E. faecium as a successful hospital-associated pathogen.
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