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Updated: May 5, 2026
Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food
Published on: May 6, 2013
Effects of microgravity on the virulence of Listeria monocytogenes, Enterococcus faecalis, Candida albicans, and
Timothy G Hammond1, Louis Stodieck, Holly H Birdsall
11 Durham VA Medical Center, Research and Development Service, Duke University School of Medicine , Durham, North Carolina.
Abstract:
To evaluate effects of microgravity on virulence, we studied the ability of four common clinical pathogens--Listeria monocytogenes, methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, and Candida albicans--to kill wild type Caenorhabditis elegans (C. elegans) nematodes at the larval and adult stages. Simultaneous studies were performed utilizing spaceflight, clinorotation in a 2-D clinorotation device, and static ground controls. The feeding rate of worms for killed E. coli was unaffected by spaceflight or clinorotation. Nematodes, microbes, and growth media were separated until exposed to true or modeled microgravity, then mixed and grown for 48 h. Experiments were terminated by paraformaldehyde fixation, and optical density measurements were used to assay residual microorganisms. Spaceflight was associated with reduced virulence for Listeria, Enterococcus, MRSA, and Candida for both larval and adult C. elegans. These are the first data acquired with a direct in vivo assay system in space to demonstrate virulence. Clinorotation reproduced the effects of spaceflight in some, but not all, virulence assays: Candida and Enterococcus were less virulent for larval worms but not adult worms, whereas virulence of MRSA and Listeria were unaffected by clinorotation in tests with both adult and larval worms. We conclude that four common clinical microorganisms are all less virulent in space.
Insights
Microgravity reduces the virulence of common clinical pathogens, including Listeria, MRSA, Enterococcus, and Candida, in Caenorhabditis elegans (C. elegans) models. This study provides the first in-vivo evidence of reduced microbial virulence during spaceflight.
Area of Science:
- Microbiology
- Space Biology
- Invertebrate Zoology
Background:
- Virulence of common clinical pathogens is a significant concern in healthcare.
- Understanding how environmental factors like microgravity affect pathogen virulence is crucial for astronaut health and potential extraterrestrial missions.
Purpose of the Study:
- To investigate the impact of microgravity on the virulence of four common clinical pathogens: Listeria monocytogenes, methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, and Candida albicans.
- To compare the effects of actual spaceflight with simulated microgravity (clinorotation) on pathogen virulence using a Caenorhabditis elegans (C. elegans) model.
Main Methods:
- Utilized a Caenorhabditis elegans (C. elegans) model to assess pathogen virulence in larval and adult stages.
- Conducted experiments in spaceflight, using a 2-D clinorotation device for simulated microgravity, and static ground controls.
- Measured pathogen virulence by assaying residual microorganisms after a 48-hour co-incubation period with C. elegans.
Main Results:
- Spaceflight was associated with significantly reduced virulence for all four tested pathogens (Listeria, Enterococcus, MRSA, and Candida) against both larval and adult C. elegans.
- Clinorotation partially replicated spaceflight effects, reducing virulence for Candida and Enterococcus in larval worms but not adult worms.
- Clinorotation did not affect the virulence of MRSA and Listeria in either larval or adult worms.
Conclusions:
- Microgravity significantly decreases the virulence of common clinical pathogens.
- This study presents the first in vivo data demonstrating reduced microbial virulence in space.
- The findings highlight the potential impact of space environments on infectious disease dynamics and emphasize the need for further research into space-related alterations in microbial pathogenicity.
