Why Bacteria in Space Are Surprisingly Tough to Kill

Bacteria in space may sound like the title of a bad science fiction movie, but it's actually a new experiment that tests how the weightlessness of space can change microbes' antibiotic resistance.

While the vacuum of space may be a sterile environment, the ships (and eventually habitats) humans travel and live in are rife with microbial life. And keeping these microbes in check will be vital for the health of the crew and even the equipment, reports George Dvorsky for Gizmodo.

Past research has shown that bacteria that would normally collapse in the face of standard antibiotics on Earth seem to resist those same drugs much more effectively in the microgravity of space, and even appear more virulent than normal. To figure out how weightlessness gives bacteria a defensive boost, samples of E. coli took a trip to the International Space Station in 2014 so astronauts could experiment with antibiotics.

Now, in a new study published this week in the journal Frontiers in Microbiology, researchers demonstrates that microgravity gives bacteria some nifty tricks that make a lot less susceptible to antibiotics. Their main defense: getting smaller.

The E. coli in space showed a 73 percent reduction in their volume, giving the bacteria much less surface area that can be exposed to antibiotic molecules, Dvorsky reports. Along with this shrinkage, the cell membranes of the E. coli grew at least 25 percent thicker, making it even harder for any antibiotic molecules to pass through them. And the defense mechanisms weren't only the individual level—the E. coli also showed a greater propensity for growing together in clumps, leaving the bacteria on the edges open to danger, but insulating those within from exposure to the antibiotics.

All of these differences allowed the E. coli on the International Space Station to grow to 13 times the population of the same bacteria grown on Earth under the same conditions, according to the study. And understanding why and how these defense mechanisms form could help doctors better prevent the scourge of antibiotic resistance here on Earth.

Perhaps even more terrifying, compared to the bacteria grown in the same conditions on Earth, the space-bound E. coli developed fluid-filled sacs called vesicles on their cell membranes, giving them tools that can make them even better at infecting other cells. This means that astro-bacteria could make people ill more easily, creating an infection that is harder to treat.

As people head further out into space, many are still afraid about what will happen when we meet alien bacterial life. But travelers into the great beyond may also need to keep a close eye out for the bacteria we already thought we knew.

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Ben Panko is a staff writer for Smithsonian.com