ASSESSMENT OF THE ADAPTABILITY OF NON-FASTIDIOUS PATHOGENIC BACTERIA TO THE MARTIAN ENVIRONMENT WITH IMPLICATIONS TO HUMAN HEALTH.

Kurzfassung

With the renewed interest in space-travel and the increase in space-missions, the risk of human microorganisms making their way to an extraterrestrial body will increased. Despite stringent decontamination protocols, terrestrial microorganisms were previously found to travel on the bodies of astronauts, on spaceships and equipment. The travelling microorganisms which are able to survive might adapt, grow and evolve in the new environment. What would happen if human pathogens made their way into space? Could they survive in environments such as the one on Mars? If they survive, would they pose a threat to astronaut safety if humans came into contact with them? Parts of these questions have been investigated by Domínguez-Andrés et al., 2020, with their paper which investigated the growth and immunological response of nonfastidious bacteria when inoculated in minimal media with sugars identified in carbonaceous meteorites. With this project, our aim was to continue the research by investigating the extent to which the same non-fastidious pathogenic bacteria (Klebsiella pneumoniae, Burkholderia cepacia, Serratia marcescens and Pseudomonas aeruginosa) can survive in simulated Martian environment. Our research showed the survival of these bacterial species to a range of simulated Martian conditions i.e., desiccation, UVC (254 nm) and polychromatic UV (200 - 400 nm) irradiation, growth in the presence of perchlorates, growth on Martian simulant and exposure to Martian atmospheric composition and pressure. Furthermore, our results show that the survival was enhanced with the addition of Mars Global simulant (mimicking Martian regolith) to the incubation media. Furthermore, these initial results showed that only two of the strains, K. pneumoniae and S. marcescens are tolerant to desiccation. The UVC irradiation experiments have shown that the bacteria with the highest degree of survival are P. aeruginosa and S. marcescens. Likewise, the same two strains have shown higher survival rates compared to K. pneumoniae and B. cepacia when exposed to polychromatic UV irradiation. To investigate the consequences of survival and growth under simulated Martian conditions, on virulence and immune recognition, we are continuing the work by analyzing the response of PBMCs and non-immune cells placed in contact with bacteria exposed to the Martian environment. This collaborative study between the DLR (German Aerospace Center) and the Radboud UMC, has provided a starting point to the investigation into the adaptability of pathogenic bacteria to Martian conditions. Further studies are required in order to improve our insight on the effects of virulence and immune recognition of the exposed pathogens. Our work could enable to potentially anticipate the risks of infection and inflammation during space-travel and exploration of planets in our solar system.