DYNAMICS OF QUALITATIVE AND QUANTITATIVE COMPOSITION OF THE MICROBIOME OF THE INTERNAL SURFACES OF THE INTERNATIONAL SPACE STATION FOR THE OBSERVATION PERIOD FROM 2016 TO 2022
Authors:   Institute of Biomedical Problems of Russian Academy of Sciences, Moscow, Osipova P.J. , Karpov D.S. ,   Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, Dymova A.A. ,   Institute of Biomedical Problems of Russian Academy of Sciences, Moscow, Shef K.A. ,   Institute of Biomedical Problems of Russian Academy of Sciences, Moscow, Zhukova E.A. ,   Institute of Biomedical Problems of Russian Academy of Sciences, Moscow, Kovalev M.A. ,   Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, Polyakov N.B. ,   Gamaleya National Research Centre for Epidemiology and Microbiology of Ministry of Public Health of Russian Federation, Moscow, Soloviev A.I. ,   Gamaleya National Research Centre for Epidemiology and Microbiology of Ministry of Public Health of Russian Federation, Moscow, Guridov A.A. ,   Institute of Biomedical Problems of Russian Academy of Sciences, Moscow, Zhukhovitsky V.G. ,   Gamaleya National Research Centre for Epidemiology and Microbiology of Ministry of Public Health of Russian Federation, Moscow, Poddubko S.V. ,   Institute of Biomedical Problems of Russian Academy of Sciences, Moscow
Published: June 2024

Residents of the International Space Station (ISS) are various types of bacteria that can act as potential biodegraders of structural materials, which entails disruptions in the operation of various equipment and, indirectly, provoke medical risks and affect the health of crew members with reduced immunity. Since the beginning of ISS exploitation sanitary and microbiological monitoring of the habitat has been carried out for the purpose of timely detection and inactivation of potentially dangerous strains. The study was conducted to investigate the dynamics of the composition and number of bacterial strain species detected on the internal surfaces of the ISS interior and equipment for the period covering from Expedition 46 to Expedition 67 (2016–2022). Samples collected from ISS interior surfaces were grown on nutrient media. Strains were identified by 16S RNA sequencing and MALDI-TOF analysis. The results obtained showed that the number of bacterial community species increases with the increase of the ISS RS operation period. However, this growth was not linear, but was a wave-like repetitive process of changing phases of activation and stagnation of the microbiome. During the period of work of Expeditions 46-67, species of the genera Bacillus and Staphylococcus dominated in the microbiome. Among representatives of the genus Bacillus, the species B. licheniformis dominated. The predominance of bacteria of this genus, apparently, is due to their high resistance to physical and chemical parameters of the ISS habitat, including DNA-damaging factors, such as increased radiation background, which, in turn, can be explained by their ability to spore formation. The results obtained once again indicate the high evolutionary plasticity of B. licheniformis strains, which we discovered earlier in other studies.