BACTERIAL POPULATIONS (NASU)
Microbiological monitoring is important to assure microbiological safety especially in long-
duration space habitation. Researchers have continuously monitored the abundance and
diversity of bacteria in the ISS-Kibo to accumulate knowledge on microbes in the ISS. In this
study, we used a new sampling device, the microbe-collecting adhesive sheet developed in our
laboratory. This adhesive sheet has high operability, needs no water for sampling, and is easy to
transport and store. We first validated the adhesive sheet as a sampling device used in space
habitat, with regard to stability of bacterial number on the sheet during prolonged storage of
up to 12 months. Bacterial abundance on the surfaces in the Kibo was then determined, and it
was lower than that on the surfaces in our laboratory (10^5 cells [cm^2 ]-1), except for the return
air grill, and bacteria detected in the Kibo were a part of the human skin microflora. From these
studies of microbial abundance and their phylogenetic affiliation, scientists concluded that the
Kibo has been microbiologically well maintained; however, microbial abundance may increase
with prolonged stay of crew members. To ensure crew safety and understand bacterial
dynamics in space habitation environments, continuous bacterial monitoring in the Kibo is
required.
PUBLICATION(S):
Ott CM, Pierson D, Shirakawa M, et al. Space habitation and microbiology: Status and roadmap
of space agencies. Microbes and Environments. 2014;29(3):239-242. doi:
10.1264/jsme2.ME2903rh.
Venkateswaran K, La Duc MT, Horneck G. Microbial existence in controlled habitats and their
resistance to space conditions. Microbes and Environments. 2014;29(3):243-249. doi: 10.1264/
jsme2.ME14032.
Yamaguchi N, Roberts M, Castro S, et al. Microbial monitoring of crewed habitats in space—
Current status and future perspectives. Microbes and Environments. 2014;29(3):250-260. doi:
10.1264/jsme2.ME14031.
Ichijo T, Hieda H, Ishihara R, Yamaguchi N, Nasu M. Bacterial monitoring with adhesive sheet in
the International Space Station “Kibo”, the Japanese experiment module. Microbes and
Environments. April 20, 2013;28(2):264-268. doi: 10.1264/jsme2.ME12184.
Satoh K, Nishiyama Y, Yamazaki TQ, et al. Microbe-I: Fungal biota analyses of Japanese
experimental module “Kibo,” International Space Station which passed for about four hundred
sixty days. Microbiology and Immunology. December 2011;55(2):823-829. doi: 10.1111/j.1348-
0421.2011.00386.x.
This experiment is complete; however additional results are pending publication.