In space, the behavior of bacteria changes dramatically and they start doing some defensive shape-shifting to protect themselves against antibiotics. This was revealed in a new study carried out at the International Space Station (ISS).

Cultures of E. coli bacteria were sent to the ISS

Understanding how bacteria behave in space is crucial for the safety of astronauts during long-distance space missions. To improve understanding of the behavior of bacteria in microgravity conditions, researchers at the University Of Colorado at Boulder planned an experimental study and sent cultures of Escherichia Coli (E.

coli) bacteria to the ISS. The experiments at the space station were carried out under the supervision of NASA astronaut Rick Mastracchio.

The primary aim of these experiments was to observe how E.coli cells respond when exposed to gentamicin sulfate, an antibiotic known to kill bacteria with ease under standard conditions on Earth. E.coli cultures were exposed to different concentrations of gentamicin sulfate on the ISS, and the resulting changes in their physical appearance were analyzed by researchers.

Bacterial cells decreased their volume when exposed to gentamicin sulfate

Luis Zea, a researcher at the University of Colorado, revealed that the volume of bacterial cells, when exposed to gentamicin sulfate, decreased by 73 percent compared to samples of same bacteria on Earth.

The reduction in the cell volume enabled these bacteria to have less surface area exposed to antibiotics. Researchers also observed a 13-fold increase in E. coli cell numbers.

Another interesting observation was the thickening of the outer membranes and cell walls of bacterial cells. Moreover, these bacteria started growing up in clumps which prevented exposure of inner cells (due to a protective shell of outer cells).

Some cells were found to be producing membrane vesicles which enabled them to communicate with other cells and potentially initiate infection process.

Experts believe this unusual behavior of bacteria in microgravity conditions could pose threat to astronauts in future space missions. Astronauts go to space with their own microbiomes that include different types of bacteria.

In the ISS, there are different surfaces where biofilms (potentially containing clumps of bacteria) can grow. In case these space bacteria develop resistance to antibiotics, they would become deadly. They would infect astronauts quickly and would also make it difficult to treat astronauts.

The detailed findings of the study were published in Frontiers in Microbiology.