Wherever people will become, our bacterial companions will follow us. Just as it is in space as on Earth, and when we know that microbial astronauts are present at the International Space Station, one group of researchers has just found a new reason to look after them.
Genomic analysis of samples taken from the space ladder on board the station revealed among others that some bacteria on the ISS have genes that provide antibiotic resistance. There is no danger to astronauts today, says researchers at NASA's Jet Propulsion Laboratory, but recalls that bacteria can be a threat in a restricted space station environment.
In this new study, scientists characterized genomes of these species in detail and compared their genomes with genomes of 1,291 Enterobacter tribes from Earth. Studies of genetic makeup of bacteria have found that bacteria are likely to be resistant to antibacterial drugs.
Nitin Singh, the first author of the study, stressed in his statement that these strains are not virulent, which means they are not an active or imminent threat to astronauts. But Singh added that one of the tribes found, Enterobacter bugandensis is an opportunistic pathogen, which means it could cause illness. Computer analysis of species has found that there really is a significant risk that people will be harmed in the future.
The work was part of an effort to better understand how future microbial astronauts will affect human life in space.
"Understanding how microbial life is growing in a closed environment like ISS will help us better prepare for the health problems that come with space travel," Singh said in an e-mail. "ISS offers us the opportunity to explore for the first time the often overlooked aspect of space travel: how space microbiology works and a system of life support," said Singh
Closed system aboard the space station is a unique environment for bacteria and other microbial organisms. Just as they grow, adjust and multiply microbial species on Earth, they will be the same in space. The boundaries and device grips and storage on board the space station are kept clean, but the microscopic organisms present find shelter and adapt to survive. As researchers found, some of these treatments could include mutations that bring antibiotic resistance and cause bacteria to be extremely difficult to fight.
By better understanding the species on board the space station, scientists hope to find out how best to protect astronauts. For example, they could know when and how often to clean some of the devices on board, Singh said.
While the bacterial species at the space station are not presently at risk, the human immune system is threatened in space, Singh explained. So on future missions in deep space, where astronauts can spend more time in space, and bacteria may have more time to adapt and multiply, the risk of infection could be higher.
"Once the immune system starts to weaken, microbes that were previously harmless could make you worse," Singh said.
This study was published in the journal BMC Microbiology.