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Genomic and Functional Characterization of Enterococcus faecalis Isolates Recovered From the International Space
Noelle C Bryan1, Francois Lebreton2,3, Michael Gilmore2
1Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States.
Abstract:
Enterococcus faecalis is a multidrug resistant, opportunistic human pathogen and a leading cause of hospital acquired infections. Recently, isolates have been recovered from the air and surfaces onboard the International Space Station (ISS). Pangenomic and functional analyses were carried out to assess their potential impact on astronaut health. Genomes of each ISS isolate, and both clinical and commensal reference strains, were evaluated for their core and unique gene content, acquired antibiotic resistance genes, phage, plasmid content, and virulence traits. In order to determine their potential survival when outside of the human host, isolates were also challenged with three weeks of desiccation at 30% relative humidity. Finally, pathogenicity of the ISS strains was evaluated in the model organism Caenorhabditis elegans. At the culmination of this study, there were no defining signatures that separated known pathogenic strains from the more commensal phenotypes using the currently available resources. As a result, the current reliance on database information alone must be shifted to experimentally evaluated genotypic and phenotypic characteristics of clinically relevant microorganisms.
Insights
Multidrug-resistant Enterococcus faecalis found on the International Space Station (ISS) poses potential risks to astronaut health. Experimental evaluation is crucial, as genomic data alone cannot distinguish pathogenic from commensal strains.
Area of Science:
- Microbiology
- Space Science
- Genomics
Background:
- Enterococcus faecalis is a multidrug-resistant pathogen causing hospital-acquired infections.
- ISS isolates of E. faecalis raise concerns about astronaut health.
- Previous studies have not fully characterized ISS E. faecalis strains.
Purpose of the Study:
- To assess the potential impact of ISS Enterococcus faecalis isolates on astronaut health.
- To compare ISS isolates with clinical and commensal strains using pangenomic and functional analyses.
- To experimentally evaluate the genotypic and phenotypic characteristics of ISS E. faecalis.
Main Methods:
- Pangenomic analysis of ISS, clinical, and commensal E. faecalis strains.
- Assessment of antibiotic resistance genes, phage, plasmid content, and virulence traits.
- Desiccation survival tests and pathogenicity evaluation in Caenorhabditis elegans.
Main Results:
- No distinct genomic signatures differentiated pathogenic from commensal E. faecalis strains.
- ISS isolates exhibited varying survival and pathogenicity traits.
- Experimental data is essential for accurate strain characterization.
Conclusions:
- Current reliance on genomic databases alone is insufficient for assessing E. faecalis pathogenicity.
- Experimental genotypic and phenotypic characterization is critical for clinically relevant microorganisms.
- Further research is needed to understand E. faecalis adaptation and survival in space environments.
