Astronauts on board the International Space Station (ISS) live and work in the hyper-organized site, packed with computers and laboratory experiments. Quarter look dated and clean.
But at the microscopic level, the ISS, as our homes and workplaces, is teeming with bacteria.
And in space, microgravity (weightlessness), cosmic radiation and psychological stress can weaken the immune system of astronauts, and at the same time stimulate the bacteria to become stronger.
German scientists study published in the journal Frontiers in microbiology showed that silver- and ruthenium based antimicrobial coating dramatically reduced the number of bacteria on surfaces exposed to contamination in the ISS.
Coating called AGXX and manufactured by the German company Largentec Vertriebs in Berlin, could help protect future astronauts.
Here on Earth, the coating being tested for possible use in hospitals and health systems, and water applications.
Elisabeth Grohmann, Ph.D., lead author of the study. She is Professor of Microbiology in the Department of Biological Sciences and Technology in the Beuth University of Applied Sciences in Berlin.
"Space flight can transform harmless bacteria in the potential pathogens," she told Healthline. "Just as the stress hormones leave astronaut vulnerable to infection, the bacterium, they are becoming tougher – the development of thick protective coatings and antibiotic resistance -. And the more energetic, faster metabolism and multiplying "
In addition, the genes responsible for these new features can be easily shared between different species of bacteria through direct contact or "matrix" of mucus they secrete, she says.
Grohmann and her colleagues conducted their research from 2013 to 2015.
The members of the ISS crew AGXX applied to the outer surface of the toilet door. Performance tests were made in the coating after 6, 12 and 19 months.
"We have successfully applied AGXX, new antimicrobial material which can be used as a coating for basically any material, from metal to plastic," said Grohmann.
"This greatly reduces the growth of bacteria, including many dangerous pathogens. Coating kills bacteria by importing toxic, highly reactive substances (active oxygen species) in bacterial cells. These chemicals attack biomolecules in bacterial membranes, thus killing the bacteria, "she explained.
After six months, no bacteria, they have not been removed from the coated surface of the ISS.
Even at 12 and 19 months, Grohmann said a total of 12 bacteria were found – a decline of 80 percent compared to uncoated surfaces.
Regular silver coating test for comparison had only little antimicrobial effect and the reduction in the number of bacteria at 30 percent.
"With a long exposure time some bacteria escaped the antimicrobial action," she said. "Antimicrobial test materials with the & # 39 are static surfaces where dead cells, dust particles, and cell debris can accumulate over time and interfere with direct contact between the bacteria and the antimicrobial surface."
AGXX contains both silver and ruthenium due to a vitamin A derivative. It kills many bacteria and some fungi, yeasts and viruses, said Grohmann.
The effects are similar to bleach, except that the coating is self-regenerating so it never gets used, it adds.
"But I want to emphasize that the study was initiated not because of health crew problems, but due to the corrosion of the material to the ISS, caused by microbial growth and biofilm formation on the rubber seals on the viewing window, and on the other the hardware surface," said Grohmann,
David Coil, Ph.D., a microbiologist and project scientist at the University of California, Davis, has also been involved in published studies of bacteria on the ISS.
"In the first study, we took a bunch of bacteria from the Earth and compared their growth to the ISS on Earth. We found that almost every bacteria grew very similar to the one that grew better in space. We did not look for resistance to antibiotics, biofilm formation, or anything like that, "he told Healthline.
"The second DNA sequencing review ISS. We looked at which bacteria are present on the surface of the ISS. Our main take-home message was that MKS is dominated by human-associated bacteria, and in fact very similar to the house in the world, "he added.
Antimicrobial coating seems to work well on Earth and the ISS, he says, but a recent study framed "in the context of alarmism more than I think it is justified," said Coil.
"There are really some of the work, which shows that bacteria behave differently on the ISS (biofilm formation, etc.), but almost none of this work has not been translated into actual increase in virulence or risk," he said. "Most of the findings in this article and references in this document do not have the appropriate context."
The study authors said that 60 percent of the bacterial strains were resistant to three or more antibiotics, said Coil.
But this discovery is nothing without a comparison with equivalent strains in the world does not mean that it shows.
"All" human pathogen "are from groups that are known to form biofilms, be resistant to antibiotics, and go horizontal gene transfer," said coils.
"What they really mean is the organism of the groups that are known to contain pathogens. think colon bacillusIt might be a pathogen, and it can also be important, beneficial bacteria in the human body. I think it's misleading to report only such data from the ISS. It is easy to conclude that these features with the & # 39 are "as" bacteria were from the ISS, "said Coil.
Coil says the study also discusses the idea of neutral and beneficial bacteria.
It's a good idea to kill everyone on board the ISS? "Probably not", said Coil.
Data from hospitals indicate that if the medical staff work hard to create a sterile environment, these environments tend to then get the colonization of the most enduring and potentially harmful micro-organisms, he says.
"Yes, astronauts influence immune function in the space," said Coil. "And yes, some of the bacteria behave differently on the ISS. But I do not think it is justified to say something like «Spaceflight can transform harmless bacteria in the potential pathogens," said Coil.
"Of course, she says," potential ", but I still think that the average person reading this suggestion would be to take home the idea that space travel makes these bugs are dangerous. I see no evidence, "he continues.
"Although I think that the data in this article in order,» Coil said, "I think it is framed too scary-sounding context and can not be the kind of solutions we want to space travel in any case."
However, the antimicrobial coating can still have a bright future in space and on Earth.
«AGXX tested for future applications, such as urinary catheters coating. The first successful study was conducted for several years, but has not yet been published, "said Grohmann.
"Other tests include its use as antimicrobial coatings for wound dressings as a nucleus which kills components ointments and lotions, as well as a water filter systems. In the future, the test will be to look at the killing germs in filters for air conditioners, "she added.
Another test examines the current AGXX effect on bacterial endospores, the most resistant life forms of some bacteria, and pathogenic human viruses that can cause disease, she says.
Institute of Biomedical Problems of the Russian Academy of Sciences in Moscow, only opened four months of isolation study using anti-microbial coatings in a manned environment, in preliminary tests and preparatory studies for future lunar and Martian expeditions, said Grohmann.
A study funded by the European Space Agency and NASA.
The goal is to determine which bacteria survive in areas of the antimicrobial coating and to evaluate possible risks to the health of the crew members, including antibiotic resistance, toxin production, virulence factors and biofilm formation.