Determining what makes microbes more drug resistant in microgravity
Future human endeavors in space may run into problems with bacteria from Earth. The microbes that cover our planet seem to be surprisingly resilient to being in space, a concern that has pushed NASA to extreme measures like destroying spacecraft to avoid contaminating new environments. Experiments on the International Space Station (ISS) suggest that we may need to develop some new medical strategies as well, as bacteria in microgravity may inadvertently make themselves more resistant to antibiotics.
Absorbing less, clumping more
In a series of experiments on the ISS, researchers observed a number of changes in Escherichia coli samples adapting to microgravity. On Earth, forces like buoyancy and sedimentation help push nutrients through bacterial cells with the help of the planet’s gravity. But in the perpetual free-fall of the ISS, these mechanisms didn’t function, leading to bacteria taking in fewer nutrients from their environments. That also meant that they had a smaller surface area to absorb medicines like antibiotics, and larger doses were needed to kill them than on Earth.
This might sound manageable, but collapsing into a more tightly packed ball wasn’t the only effect of microgravity. The E. coli on the ISS also tended to grow in clumps, which researchers worry will lead to the formation of more biofilms, which are defensive structures bacteria use to repel both medicines and immune systems. Beyond that, the microbes also grew extra outer membrane vesicles, which are small structures bacteria use to communicate with each other. This can often lead to faster infections in a body, as well as mitigate the effects of antibiotics to a degree.
Silver lining?
This may sound like the first bacterial outbreak in space will be unstoppable, but researchers are still optimistic. Understanding what microgravity does to bacteria can help us develop new techniques beyond simply increasing the doses of antibiotics. There’s a chance that further study will reveal the underlying principles that shape bacteria that may normally be obscured by the Earth’s gravity. If weaknesses can be found, this may allow us to fight bacterial infections in space and at home in new ways. It should also help us understand what happens to the bacteria we want in our bodies, since they’re needed for our immune health, digestion and more.
Source: Why bacteria 'shapeshift' in space by Jim Scott, Phys.org
