Preparing for the crewed Mars journey: microbiota dynamics in the confined Mars500 habitat during simulated Mars flight and landing

Abstract

BackgroundThe Mars500 project was conceived as the first full duration simulation of a crewed return flight to Mars. For 520 days, six crew members lived confined in a specifically designed spacecraft mock-up. The herein described “MIcrobial ecology of Confined Habitats and humAn health” (MICHA) experiment was implemented to acquire comprehensive microbiota data from this unique, confined manned habitat, to retrieve important information on the occurring microbiota dynamics, the microbial load and diversity in the air and on various surfaces.In total, 360 samples from 20 (9 air, 11 surface) locations were taken at 18 time-points and processed by extensive cultivation, PhyloChip and next generation sequencing (NGS) of 16S rRNA gene amplicons.ResultsCultivation assays revealed a Staphylococcus and Bacillus-dominated microbial community on various surfaces, with an average microbial load that did not exceed the allowed limits for ISS in-flight requirements indicating adequate maintenance of the facility. Areas with high human activity were identified as hotspots for microbial accumulation. Despite substantial fluctuation with respect to microbial diversity and abundance throughout the experiment, the location within the facility and the confinement duration were identified as factors significantly shaping the microbial diversity and composition, with the crew representing the main source for microbial dispersal. Opportunistic pathogens, stress-tolerant or potentially mobile element-bearing microorganisms were predicted to be prevalent throughout the confinement, while the overall microbial diversity dropped significantly over time.ConclusionsOur findings clearly indicate that under confined conditions, the community structure remains a highly dynamic system which adapts to the prevailing habitat and micro-conditions. Since a sterile environment is not achievable, these dynamics need to be monitored to avoid spreading of highly resistant or potentially pathogenic microorganisms and a potentially harmful decrease of microbial diversity. If necessary, countermeasures are required, to maintain a healthy, diverse balance of beneficial, neutral and opportunistic pathogenic microorganisms. Our results serve as an important data collection for (i) future risk estimations of crewed space flight, (ii) an optimized design and planning of a spacecraft mission and (iii) for the selection of appropriate microbial monitoring approaches and potential countermeasures, to ensure a microbiologically safe space-flight environment.Electronic supplementary materialThe online version of this article (10.1186/s40168-017-0345-8) contains supplementary material, which is available to authorized users.

ANCHOR: a 16S rRNA gene amplicon pipeline for microbial analysis of multiple environmental samples

“…and Finegoldia sp. in crew quarters, illustrating the value and strong design of the Mars500 project (Schwendner et al ., ). Beyond this, while previous research highlights that domination of the ISS by human GIT bacteria is unsurprising, given humans are the only source of bacteria entering the environment, ANCHOR reveals laboratory surfaces also harbour bacteria deriving from those other microbiome carrying animals travelling upon the ISS, research facility rodents.…”

The influence of bioregenerative life‐support system dietary structure and lifestyle on the gut microbiota: a 105‐day ground‐based space simulation in Lunar Palace 1

“…The maintenance of human health has been focused on as a crucial issue for realizing manned deep-space exploration (Mora et al, 2016a;Kuda et al, 2017;White, 2017). The gut microbiota is essential to health; it plays a vital role in host physiology, metabolism, nutrition and immune system development (Dore and Blottiere, 2015;Greenhalgh et al, 2016;Lv et al, 2016); dysbiosis of the gut microbiota is associated with illness and infection (Liu, 2016;Schwendner et al, 2017). Hence, one of the major challenges in manned space exploration is protecting astronauts from microbiota dysbiosis.…”

“…Hence, one of the major challenges in manned space exploration is protecting astronauts from microbiota dysbiosis. In recent years, with the development of high-throughput sequencing technology for complex microbial communities, both hostderived and environmental microbiome have frequently been studied, either in space stations (Checinska et al, 2015;Moissleichinger et al, 2016;Mora et al, 2016b;Be et al, 2017) or ground-based space simulations Mayer et al, 2016;Sun et al, 2016;Blachowicz et al, 2017;Schwendner et al, 2017;Turroni et al, 2017).…”

Precision public health to inhibit the contagion of disease and move toward a future in which microbes spread health

“…argue against increasing the safety of hospital workers and patients? Who could argue against greater microbiological safety and health for the crew of long term space flights who live at close quarters for months at a time [110]? If there were clear evidence for wider public health benefit, how could we not do this?…”