It is well known that a living and working environment in the International Space Station (ISS) has been progressively contaminated by a number of microorganisms since the beginning of its construction. These microorganisms may cause serious life-threatening diseases and allergies if the immune system is compromised. The objective of this study was to evaluate the risk of inhalation of microorganisms when breathing and of adhesion to the skin which is exposed to ambient air during a stay in the ISS. The detailed analysis included culture-based analyses and the latest molecular genetics methods which focused particularly on fungi which act as strong allergens in a living environment. Microbiota of these samples is thought to be strongly reflected by that of the ISS environment, which has a completely closed orbital living space under microgravity.
The Myco experiment was one in a series of studies on exposure biology. It has already been reported that a number of microorganisms have been detected in space stations such as the Russian Mir and the ISS. Penicillium sp.
and Aspergillus sp.
have been dominant fungal species in both of these space stations. It is well known that Penicillium sp.
and Aspergillus sp.
act as strong allergens in our living environment and allergies that are caused by these molds is recognized as a serious problem from the medical point of view. Many researchers are studying the correlation between environmental microbiota and allergic reactions caused by an exposure to a living environment.
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Samples from both nasal cavities, the pharynx, the skin of both cheeks, and from the upper chest area were collected by medical cotton swabs and dressing tapes. Sputum samples were collected by expectorating into sputum tubes. Preflight data was performed two times each for ISS and Shuttle crewmembers. Preflight data collections for the ISS crew and Shuttle crewmembers was done between L-60 and 30 days and between L-10 and 5 days before their launch by Soyuz or Space Shuttle. Postflight sessions were performed two times each for the ISS and Shuttle crewmembers. Postflight, the sames activites were done between R+0 and 3 days and between R+30 and 60 days after their return by Soyuz or Space Shuttle.
The ISS and Shuttle crewmembers collected the samples themselves using sample collection kits on board in the same way pre- and postflight baseline data was collected. The in-flight data collection was done by both the ISS and Shuttle crewmembers during a spacecraft docking to ISS and within 36 hours before closing the hatch when leaving the ISS. Collected samples were stowed at 4ºC.
Preliminary results showed that colonies of bacteria, yeast, and mold decreased on the station but fungal DNA on skin samples increased. These results are useful for air quality and radiation exposure measurements in airplanes and other environments. Additional analyses of the samples by culture-based methods and the latest molecular-genetic methods were underway.
Preliminary results also showed that the number of Colony Forming Units (CFU) tended to decrease aboard the ISS and recovered after the return. However, the amount of fungal DNA extracted from skin samples increased during spaceflight. Additional detailed microbial analysis of these samples by culture-based methods, and the latest molecular-genetic methods are underway.