Watch Bacteria Evolve to Become Antibiotic Resistant

Antibiotic resistance is one of the “biggest threats to global health today,” according to the World Health Organization, and as antibiotic use has become more widespread, bacteria are evolving to survive what used to be lethal doses of medicine. Now, you can view that evolution for yourself, as Gizmodo reports. The research is published in the latest issue of Science.

Researchers from Harvard Medical School and Technion-Israel Institute of Technology built a giant rectangular Petri dish—two-by-four-feet wide!—and dumped in 14 liters of agar, the jelly substance used to culture bacteria in the lab. They divided the Petri dish into sections, then watched as E. coli bacteria reacted to various doses of antibiotics in each part of the dish. The outermost section of the dish contained no antibiotics, the next just enough antibiotics to kill the bacteria, and so on. The highest dose of antibiotic administered (seen in the center of the dish) was 1000 times stronger than the lowest dose. Over the course of two weeks, scientists used a ceiling camera to watch as the bacteria adapted to their new environment, then turned the footage into a timelapse.

The bacteria could move through the sections of antibiotics, and as the bacteria reproduced and mutated, they moved into higher and higher dosed sections. The high doses of antibiotic initially killed many of the bacteria, but some microorganisms that started out in the lower doses of antibiotics mutated and evolved, allowing their descendants to survive more and more of the drug. After 10 days, some of the bacteria had evolved to survive the highest dose of antibiotics.

While Petri dishes aren’t an exact analog for the way bacteria evolve in real-life settings like hospitals, the visualization provides a scary glimpse into how bacteria can mutate to confound modern drugs. Watch it below, and remember: Take antibiotics only as prescribed, and skip the antibacterial soaps entirely! (They'll be banned soon anyway.)

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