Bacteria aboard the International Space Station (ISS) were found changing their shape after being treated with a common antibiotic used to kill them on Earth.

E. Coli Bacteria Behave Differently In Microgravity Conditions In Space

Luis Zea, from the University of Colorado, and colleagues sent samples of E.coli bacteria to the ISS to learn how microbes behave in microgravity environment.

The researchers studied how bacteria grow and responded to the antibiotic gentamicin sulfate that kills them under normal conditions on Earth. During the experiments, the researchers analyzed the changing physical appearance of the bacteria that were treated with different concentrations of antibiotic in space.

Zea and colleagues found that E.coli cell size decreased by 73 percent compared to samples of the bacteria on Earth. The reduction in cell volume gives the bacteria less surface that can be exposed to molecules of antibiotics.

They also observed that the samples aboard the ISS developed thicker cell wall and membrane, which they think can help the bacteria protect themselves from antibiotic. Thicker cell wall and membrane can make it harder for antibiotic molecules to pass through the bacteria.

Some cells were also observed to produce membrane vesicles that allowed them to communicate with each other and potentially set off the infection process.

The behavior of E. coli on space allowed them to grow to 13 times the population of the samples that were grown on Earth under the same condition.

"This experiment and others like it give us the opportunity to better understand how bacteria become resistant to antibiotics here on Earth," Zea said.

The researchers also noticed that the space samples formed in clumps more hinting that a defensive strategy to sacrifice outer cells to protect the inner ones, which could be potentially related to the formation of biofilms, multicellular communities that can form over time on various surfaces and could pose risk on space travels.

"While E. coli suspension cultures on Earth were homogenously distributed throughout the liquid medium, in space they tended to form a cluster, leaving the surrounding medium visibly clear of cells. This cell aggregation behavior may be associated with enhanced biofilm formation observed in other spaceflight experiments." the researchers reported in their study, which was published in the journal Frontiers in Microbiology on Aug. 28.

Shape-Shifting Bacteria May Pose Problem To Future Space Travels

The newly-observed behavior of bacteria in microgravity could mean problems in future space explorations since this could make it difficult to treat astronauts who contract infections. Even common infections could become deadly if space bacteria quickly and effectively develop resistance to antibiotics.

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