Over two weeks, a camera mounted on the ceiling above the dish took periodic snapshots that the researchers spliced into a time-lapsed montage. The result? A powerful, unvarnished visualization of bacterial movement, death and survival; evolution at work, visible to the naked eye.

The device, dubbed the Microbial Evolution and Growth Arena (MEGA) plate, represents a simple, and more realistic, platform to explore the interplay between space and evolutionary challenges that force organisms to change and adapt or die, the researchers said.

“We know quite a bit about the internal defense mechanisms bacteria use to evade antibiotics but we don’t really know much about their physical movements across space as they adapt to survive in different environments,” said study first author Michael Baym, a research fellow in systems biology at HMS.

The researchers caution that their giant petri dish is not intended to perfectly mirror how bacteria adapt and thrive in the real world and in hospital settings, but it does mimic more closely the real-world environments bacteria encounter than traditional lab cultures. This is because, the researchers say, in bacterial evolution, space, size and geography matter. Moving across environments with varying antibiotic strengths poses a different challenge for organisms than they face in traditional lab experiments that involve tiny plates with homogeneously mixed doses of drugs.

 

Eoin Treacy's view

There are encouraging advances occurring in the development of antibacterial medicines using new kinds of antibiotics, phages and genetics. Considering the rates at which bacteria can mutate we are going to need them all.