Assessment of the survivability of non-fastidius pathogens to the Martian environment

Kurzfassung

Understanding the extent to which non-fastidious pathogenic bacteria can survive in extraterrestrial conditions is key to understand astronaut safety. Despite stringent decontamination protocols, terrestrial microorganisms will be involved during human exploration of celestial bodies such as the Moon and Mars. It can be suggested that the microorganisms could adapt, grow and evolve in the new environment. In this study, we assessed the adaptability of clinically relevant bacteria species, which are able to grow in minimal media supplemented with a single carbon source identified in carbonaceous meteorites (Klebsiella pneumoniae, Burkholderia cepacia, Serratia marcescens and Pseudomonas aeruginosa), to the simulated Martian environment. Previous work has shown that bacterial survival and growth under these conditions leads to changes to their cell envelope, altering their pathogenic potential. We continued with this line of research and explored 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. Our results show that growth was enhanced by the addition of Mars Global simulant (mimicking Martian regolith) to the incubation media and that the bacteria were able to survive to an extent Martian simulated conditions. To investigate the consequences of survival and growth under simulated Martian conditions, on virulence and immune recognition, a follow-up study is analyzing the response of immune cells placed in contact with bacteria exposed to the Martian environment. This collaboration between the DLR (German Aerospace Center) and the Radboud UMC, in the Netherlands has provided a starting point to the investigation into the adaptability of pathogenic bacteria to simulated Martian environments. Further studies are required in order to improve our insight on the effects of virulence and immune recognition of the exposed pathogens. This knowledge could enable us to potentially anticipate the risks of infection and inflammation during space-travel and exploration.