The safety of the International Space Station (ISS) crewmembers and maintenance of ISS hardware are the primary rationale for monitoring microorganisms in this closed habitat. The composition of the microbial community of this built environment is unique due to microgravity space radiation and elevated carbon dioxide levels. As built environments are known to have their own microbiomes next-generation sequencing methods have to be utilized to explore the ISS microbial profile and use this data for further development of safety and maintenance practices. ISS vacuum cleaner bag components (surface) and high-efficiency particulate arrestance (HEPA) filter element (air) samples were analyzed by traditional cultivation adenosine triphosphate (ATP) and propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) assays to estimate viable microbial populations. In addition vacuum cleaner bag components of two cleanrooms at Jet Propulsion Laboratory (JPL Pasadena CA) were examined concurrently. The 16S rRNA gene sequencing based on Illumina platform was used to elucidate the ISS microbial diversity and explore differences between the microbiomes of the ISS and Earth-based cleanrooms. The statistical analyses of these microbiomes show that Actinobacteria Firmicutes and Proteobacteria dominate in the air and surface of the ISS and the cleanroom samples but vary in abundance. While members of Actinobacteria were predominant in the ISS Proteobacteria the least abundant phylum in the ISS dominated the Earth-based cleanrooms. The viable bacterial population (PMA-treated samples) decreased significantly but the treatment did not appear to have an effect on the bacterial composition (diversity) associated with a sampling site. Viable fungal sequences were not retrieved from the ISS HEPA sample where as highest viable fungal diversity was observed in the Earth-based cleanroom (JPL class 100K) debris. The results of this study provided strong evidence of substantial contribution of human skin-associated microorganisms such as Corynebacterium/Propionibacterium (Actinobacteria),not Staphylococcus (Firmicutes) species as the dominant species in the ISS in terms of viable and total bacterial community structure.

The safety of the International Space Station (ISS) crewmembers and maintenance of ISS hardware are the primary rationale for monitoring microorganisms in this closed habitat. The composition of the microbial community of this built environment is unique due to microgravity, space radiation, and elevated carbon dioxide levels. As built environments are known to have their own microbiomes, next-generation sequencing methods have to be utilized to explore the ISS microbial profile, and use this data for further development of safety and maintenance practices. ISS vacuum cleaner bag components (surface) and vacuum cleaner bag components of two cleanrooms at Jet Propulsion Laboratory (JPL, Pasadena, CA) were examined. 16S rRNA gene and ITS sequencing based on the 454 platform was used to elucidate the ISS microbial diversity and explore differences between the microbiomes of the ISS and Earth-based cleanrooms.

Presented here is the environmental microbiome study of the International Space Station surfaces. The environmental samples were collected with the polyester wipes from eight different locations in the ISS during two consecutive sampling sessions (three months apart). The specific objective was to unveil the pool of genes for each location during two separate sessions to learn of functional and metabolic diversity of microorganisms in the ISS. The International Space Station (ISS) as a closed built environment has its own environmental microbiome which is shaped by microgravity, radiation, and limited human presence. The microbial diversity associated with ISS environmental surfaces was investigated during this study. Polyester wipes and contact slides were used for sampling of eight various surface locations on the ISS at different time periods. The samples were retrieved and analyzed immediately upon the return to the Earth (via Soyuz TMA-14M or Dragon capsule from SpaceX). After surface sample collection, contact slides containing nutrient media for the growth of bacteria and fungi were incubated at 25C. The polyester wipes were processed to measure microbial burden (R2A, Blood Agar, and Potato Dextrose Agar) and recover cultivable bacteria as well as fungi. Subsequently, viable microbial burden was assessed using Adenosine Triphosphate (ATP) assay, and quantitative polymerase chain reaction (PCR) methods after propidium monoazide (PMA) treatment. The 16S-tag and metagenome analyses were used to elucidate viable microbial diversity. The cultivable bacterial population yield from the polyester wipes was very high (5 to 7-logs) when compared with the contact slides (10^2 to 10^3 CFU/m2). The PMA-qPCR analysis showed considerable variation of viable bacterial population (10^5 to 10^9 16S rDNA gene copies/m2) among locations sampled. Unlike contact slides, polyester wipes cover much larger sample surface (~1 m2) and produce much more reliable results of the microbial diversity of the ISS covering both cultivable and non-cultivable species. The cultivable, total, and viable microbial diversity was determined utilizing state-of-the art molecular techniques. The implementation of the PMA assay before DNA extraction allowed distinguishing viable microorganisms, which is crucial for determining their role to the crew health, the ISS maintenance and the general knowledge of the closed environmentally controlled built systems.

This study investigated the interplay between the microbial community of the International Space Station and its crew. Environmental samples were collected from 8 habitable locations around the ISS. The microbial composition was measured using shotgun metagenomic sequencing and procesed using the Livermore Metagenomics Analysis Toolkit.

On Earth, people spend 90% of their time indoors where dust and moisture can facilitate rapid microbial growth, especially fungi. The International Space Station is a specialized closed environment that contains own unique indoor microbiome. Elevated moisture such as from a temporary ventilation system malfunction may lead to unintended microbial growth indoors, which is associated with negative health outcomes and degradation of essential built environment materials. We need to develop a predictive approach for modeling microbial growth to understand when it may occur in these critical indoor spaces. Here we demonstrate that exposure to even fluctuating elevated relative humidity above 80% can lead to rapid microbial growth and community composition changes in dust from spacecraft. We were able to model fungal growth in space station dust using the time-of-wetness framework with activation and deactivation limited growth occurring at 85% and 100% relative humidity conditions, respectively. Alpha and beta diversity of fungi was altered with both significantly decreasing as relative humidity and time elevated increased. Our results demonstrate that we can use moisture conditions to develop predictive models for fungal growth and composition. Understanding microbial growth in spacecraft can protect astronaut health, spacecraft integrity, and promote planetary protection as human activity increases in low-Earth orbit, the moon, Mars, and beyond.

This study investigated the interplay between the microbial community of the International Space Station and its crew. Environmental samples were collected from 8 habitable locations around the ISS. The microbial composition was measured using shotgun metagenomic sequencing and procesed using the Livermore Metagenomics Analysis Toolkit.

Presented here is the environmental microbiome study of the International Space Station surfaces. The environmental samples were collected with the polyester wipes from eight different locations in the ISS during two consecutive sampling sessions (three months apart). The specific objective was to unveil the pool of genes for each location during two separate sessions to learn of functional and metabolic diversity of microorganisms in the ISS. The International Space Station (ISS) as a closed built environment has its own environmental microbiome which is shaped by microgravity radiation and limited human presence. The microbial diversity associated with ISS environmental surfaces was investigated during this study. Polyester wipes and contact slides were used for sampling of eight various surface locations on the ISS at different time periods. The samples were retrieved and analyzed immediately upon the return to the Earth (via Soyuz TMA-14M or Dragon capsule from SpaceX). After surface sample collection contact slides containing nutrient media for the growth of bacteria and fungi were incubated at 25 xcb x9aC. The polyester wipes were processed to measure microbial burden (R2A Blood Agar and Potato Dextrose Agar) and recover cultivable bacteria as well as fungi. Subsequently viable microbial burden was assessed using Adenosine Triphosphate (ATP) assay and quantitative polymerase chain reaction (PCR) methods after propidium monoazide (PMA) treatment. The 16S-tag and metagenome analyses were used to elucidate viable microbial diversity. The cultivable bacterial population yield from the polyester wipes was very high (5 to 7-logs) when compared with the contact slides (102 to 103 CFU/m2). The PMA-qPCR analysis showed considerable variation of viable bacterial population (105 to 109 16S rDNA gene copies/m2) among locations sampled. Unlike contact slides polyester wipes cover much larger sample surface (~1 m2) and produce much more reliable results of the microbial diversity of the ISS covering both cultivable and non-cultivable species. The cultivable total and viable microbial diversity was determined utilizing state-of-the art molecular techniques. The implementation of the PMA assay before DNA extraction allowed distinguishing viable microorganisms which is crucial for determining their role to the crew health the ISS maintenance and the general knowledge of the closed environmentally controlled built systems.

The microbial tracking-1 (MT-1) investigation allowed the characterization of the microbial population aboard the International Space Station (ISS).

The International Space Station (ISS) is a unique habitat for humans and microorganisms. Here, we report the results of the ISS experiment EXTREMOPHILES, including the analysis of microbial communities from several areas aboard at three time points. We assess microbial diversity, distribution, functional capacity and resistance profile using a combination of cultivation-independent analyses (amplicon and shot-gun sequencing) and cultivation-dependent analyses (physiological and genetic characterization of microbial isolates, antibiotic resistance tests, co-incubation experiments). We show that the ISS microbial communities are highly similar to those present in ground-based confined indoor environments and are subject to fluctuations, although a core microbiome persists over time and locations. The genomic and physiological features selected by ISS conditions do not appear to be directly relevant to human health, although adaptations towards biofilm formation and surface interactions were observed. Our results do not raise direct reason for concern with respect to crew health, but indicate a potential threat towards material integrity in moist areas.

Presented here is the environmental microbiome study of the International Space Station surfaces. The environmental samples were collected with the polyester wipes from eight different locations in the ISS during two consecutive sampling sessions (three months apart). The specific objective was to unveil the pool of genes for each location during two separate sessions to learn of functional and metabolic diversity of microorganisms in the ISS. The International Space Station (ISS) as a closed built environment has its own environmental microbiome which is shaped by microgravity, radiation, and limited human presence. The microbial diversity associated with ISS environmental surfaces was investigated during this study. Polyester wipes and contact slides were used for sampling of eight various surface locations on the ISS at different time periods. The samples were retrieved and analyzed immediately upon the return to the Earth (via Soyuz TMA-14M or Dragon capsule from SpaceX). After surface sample collection, contact slides containing nutrient media for the growth of bacteria and fungi were incubated at 25C. The polyester wipes were processed to measure microbial burden (R2A, Blood Agar, and Potato Dextrose Agar) and recover cultivable bacteria as well as fungi. Subsequently, viable microbial burden was assessed using Adenosine Triphosphate (ATP) assay, and quantitative polymerase chain reaction (PCR) methods after propidium monoazide (PMA) treatment. The 16S-tag and metagenome analyses were used to elucidate viable microbial diversity. The cultivable bacterial population yield from the polyester wipes was very high (5 to 7-logs) when compared with the contact slides (10^2 to 10^3 CFU/m2). The PMA-qPCR analysis showed considerable variation of viable bacterial population (10^5 to 10^9 16S rDNA gene copies/m2) among locations sampled. Unlike contact slides, polyester wipes cover much larger sample surface (~1 m2) and produce much more reliable results of the microbial diversity of the ISS covering both cultivable and non-cultivable species. The cultivable, total, and viable microbial diversity was determined utilizing state-of-the art molecular techniques. The implementation of the PMA assay before DNA extraction allowed distinguishing viable microorganisms, which is crucial for determining their role to the crew health, the ISS maintenance and the general knowledge of the closed environmentally controlled built systems.