Microbial Colonization of Space Stations

Introduction

Long-term space station missions to date include Salyut, Almaz, Skylab, Mir, ISS (International Space Station), and Tiangong, with the latter two still ongoing. These expeditions demonstrate that space stations support a diverse microbial community. While most microbes are not harmful, routine microbial monitoring onboard space stations is still essential in preventing material biodeterioration[2] and maintaining crew health[3]. As currently identified, these microorganisms originate from Earth, with main source coming from crewmembers themselves and from materials manufactured on ground. [4] Environmental monitoring is important in identifying microbe and providing data for future studies in attempt to minimize microbial threat to crewmembers’ performance and spacecrafts’ health.

Physical Environment

Microorganisms exist in the portable water, ventilating air, and on surfaces of space stations. [4] While these microorganisms share the same living space as the crewmembers, the crewmembers themselves also serve as incubators for various microbes. [5] Researchers have identified several strains of bacteria and fungi as opportunistic pathogen that may pose threats to crewmember. (refer to Key Microorganism section) Moreover, they have also identified the type of microbes responsible for biodegradation of structural materials. [6] (refer to Biodegradation section)

Microbial Diversity and Interactions

Other than in portable water and air, bacteria and fungi typically co-exist in biofilms on surfaces, including water pipe lines. [7] Biofilms provides suitable growth conditions, and intrinsically contribute to antibiotic and biocide resistance[13] due to horizontal gene transfer of antibiotic resistance plasmid, and the fact that microbes positioned inside biofilms are harder to reach. One study shows that as much as 36 species of fungi and 58 species of bacteria can co-exist in a single biofilm.[16] However, the composition varies drastically due to dynamic (changing) environmental conditions, available nutrient (surface materials), and also the thickness of biofilm.[16] In addition, exchange of microflora carried by crewmembers travelling to and from the space craft also increases microbial diversity onboard space stations.[12]

References

Text

[1] van Tongeren, S. P., Krooneman, J., Raangs, G. C., Welling, G. W. and Harmsen, H. J. M. “Microbial detection and monitoring in advanced life support systems like the International Space Station.” Microgravity Science and Technology, 2007, DOI: 10.1007/BF02911866

[2] Gu, J. “Microbial colonization of polymeric materials for space applications and mechanisms of biodeterioration: A review.” International Biodeterioration & Biodegradation, 2007, http://dx.doi.org/10.1016/j.ibiod.2006.08.010

[3] Castro, V. A., Thrasher, A. N., Healy, M., Ott C. M., and Pierson, D. L. “Microbial Characterization during the Early Habitation of the International Space Station.” Microbial Ecology, 2004, DOI: 10.1007/s00248-003-1030-y

[4] Pierson, D. L. “Microbial Contamination of Spacecraft.” Journal of the American Society for Gravitational and Space Biology, 2001, cited October 2012. http://gravitationalandspacebiology.org/index.php/journal/article/view/261

[5] Ilyin, V. K. “Microbiological status of cosmonauts during orbital spaceflights on Salyut and Mir orbital stations.” Acta Astronautica, 2005, http://dx.doi.org/10.1016/j.actaastro.2005.01.009

[6] Novikova, N., De Boever, P., Poddubko, S., Deshavaya, E., Polokarpov, N., Rakova, N., Coninx, I. and Mergeay, M. “Survey of environmental biocontamination on board the International Space Station.” Research in Microbiology, 2006, http://dx.doi.org/10.1016/j.resmic.2005.07.010

[7] Vesper, S. J., Wong, W., Kuo, C. M. and Pierson, D. L. “Mold species in dust from the International Space Station identified and quantified by mold-specific quantitative PCR.” Research in Microbiology, 2008, http://dx.doi.org/10.1016/j.resmic.2008.06.001

[8] NASA: International Space Station, cited October 2012. http://www.nasa.gov/mission_pages/station/main/index.html

[9] Robinson, J. A., Thumm, T. L. and Thomas, D. A. “NASA utilization of the International Space Station and the Vision for Space Exploration.” Acta Astronautica, 2007, http://dx.doi.org/10.1016/j.actaastro.2007.01.019

[10] Barbosa, R.C. “China launches TianGong-1 to mark next human space flight milestone.” NASASpaceFlight.com, 2011, cited October 2012. http://www.nasaspaceflight.com/2011/09/china-major-human-space-flight-milestone-tiangong-1s-launch/

[11] Gunter, D., Flores, G., Effinger, M., Maule, J., Wainwright, N., Steele, A., Damon, M., Wells, M., Williams, S., Morris, H. and Monaco, L. “Rapid Monitoring of Bacteria and Fungi aboard the International Space Station (ISS)” NASA Technical Reports Server (NTRS), 2009, http://naca.larc.nasa.gov/search.jsp?R=20090017684&qs=N%3D4294950110%2B4294848119%2B4294301177

[12] Klaus, D. M. and Howard, H. N. “Antibiotic efficacy and microbial virulence during space flight.” Trends in Biotechnology, 2006, http://dx.doi.org/10.1016/j.tibtech.2006.01.008

[13] Gu, J., Roman, M., Esselman, T. and Mitchell, R. “The role of microbial biofilms in deterioration of spacestation candidate materials.” International Biodeterioration & Biodegradation, 1998, http://dx.doi.org/10.1016/S0964-8305(98)80005-X

[14] La Duc, M. T., Sumner, R., Pierson, D., Venkat, P. and Venkateswaran, K. “Evidence of pathogenic microbes in the International Space Station drinking water: reason for concern?” UK Pubmed Central, 2004, cited on October 2012. http://ukpmc.ac.uk/abstract/MED/15880908/reload=0;jsessionid=40fVP5QP57u3BxVyDAfi.4

[15] La Duc, M. “103rd General Meeting of the American Society for Microbiology.” American Society for Microbiology, 2003, cited October 2012. http://www.asm.org/index.php?option=com_content&view=article&id=4205&title=How+Do+I+Get+My+First+Position+as+a+Microbiologist%3F+&Itemid=302

[16] Klintworth, R. and Reher, H. J. “Biological induced corrosion of materials II: New test methods and experiences from Mir station.” Acta Astronautica, 1999, http://dx.doi.org/10.1016/S0094-5765(99)00069-7

Image

[1] “STS-135 Shuttle Mission Imagery.” NASA, cited November 2012. http://spaceflight.nasa.gov/gallery/images/shuttle/sts-135/html/s135e011814.html

[2] “Astronaut Gloves Tested for Biological Contamination.” SPACE.com, cited November 2012. http://www.space.com/6486-astronaut-gloves-tested-biological-contamination.html