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Survey of genomic diversity among Enterococcus faecalis strains by microarray-based comparative genomic hybridization
Agot Aakra1, O Ludvig Nyquist, Lars Snipen
1Laboratory of Microbial Gene Technology, Department of Chemistry, Biotechnology and Food Science, The Norwegian University of Life Sciences, P.O. Box 5003, N-1432 As, Norway. agot.aakra@umb.no
Applied and Environmental Microbiology
|January 16, 2007
Summary
Comparative genomic hybridization revealed significant gene content diversity among Enterococcus faecalis strains. Key variations were observed in antibiotic resistance, virulence factors, and mobile DNA regions, highlighting ecological and systematic differences.
Area of Science:
- Microbiology
- Genomics
- Bacterial Evolution
Background:
- Enterococcus faecalis is a significant bacterium with diverse environmental origins.
- Understanding genome diversity is crucial for ecological and systematic insights.
- Comparative genomic hybridization (CGH) is a valuable tool for exploring bacterial genome variation.
Purpose of the Study:
- To compare the genomic content of nine Enterococcus faecalis strains against the reference strain V583 using CGH.
- To identify gene content variations, including divergent and absent genes, across different E. faecalis strains.
- To investigate the ecological and systematic implications of observed genomic diversity.
Main Methods:
- Comparative genomic hybridization (CGH) using microarrays.
- Analysis of gene presence, absence, and divergence against the reference strain E. faecalis V583.
- Verification of metabolic capabilities using API 50 CH assays.
Main Results:
- Significant gene content diversity was observed, with 15% to 23% of genes divergent in test strains compared to V583.
- 154 genes were found to be divergent across all tested strains.
- Variations were concentrated in regions of mobile or exogenously acquired DNA, including antibiotic resistance genes, virulence factors, and plasmid-related genes.
- Transport, metabolic, and stress tolerance gene content appeared largely conserved.
Conclusions:
- Enterococcus faecalis exhibits substantial genomic diversity, particularly in mobile genetic elements.
- Antibiotic resistance and virulence factors are key areas of genomic variation.
- The conserved nature of metabolic and stress tolerance genes supports E. faecalis's adaptability to harsh environments.
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