Not since the 1995 medical disaster movie Outbreak has a video made us quite as germophobic as this time-lapse demonstration of bacteria’s ability to evolve its way around antibiotics.
Carried out by researchers at Technion-Israel Institute of Technology and Harvard Medical School, the video tracks the evolution of a strain of bacteria across a giant Petri dish — 120cm in length — as it mutates to cope with increasingly large doses of the antimicrobial drugs doctors use to prevent the spread of bacterial infections.
By the point at which the bacteria reaches the center of the Petri dish, it is shrugging off 3,000 times the amount of antibiotic that E. coli can usually tolerate.
“What this video shows is evolution in action,” Professor Roy Kishony of Technion-Israel Institute of Technology and Harvard Medical School told Digital Trends. “For most people, evolution is this vague idea that they have. It’s something people have heard of conceptually, but they don’t get to see it happen with their own eyes. What this work does is to offer a demonstration of it taking place. It shows how easy it is for bacteria to evolve to become resistant to antibiotics.”
Easy may be a strong word. In fact, what helps the bacteria spread is, in short, the brute force of large numbers.
“The chances of bacteria evolving to overcome antibiotics is very, very small; it’s about one in a billion,” Professor Kishony continued. “But because this experiment takes place on such a large scale, we have a population size consisting of billions of bacteria. The chances of any one of them mutating is still tiny, but we keep rolling the dice 1 billion times and, after a while, one of them is going to evolve in the right way.”
The video has already caused quite a stir, and Professor Kishony said it is scheduled to be shown at a United Nations meeting next week. It is accompanied by a paper, co-authored by Michael Baym, a postdoctoral fellow in the Kishony lab at Harvard Medical School, and Tami Lieberman, a Ph.D. student at the Kishony lab and now a postdoc at MIT.
Now if you’ll excuse us, we’d like to go wash our hands!