How gut microbes bounce back after gut bug attacks

Scientists picked 25 female lab mice and watched how their stomach and gut bacteria changed after an infection with Helicobacter pylori—the same bug that causes most stomach ulcers and even cancer in humans. For one week the mice hosted the invader, then for another month they got powdered Weizmannia coagulans BC99 in three doses: tiny, medium, and large. At the end, the big-dose group showed the clearest recovery.Instead of just counting bacteria like a grocery list, researchers built a map of who talks to whom in the gut’s neighborhood. The map uses something called “information gain, ” a way to spot which microbes are the real connectors. H. pylori mainly crashed one part of the map, but BC99 rebuilt it and lifted the map’s overall score from 0. 39 to 0. 60 in the gut and from 0. 53 to 0. 62 in the stomach. Blood tests that measure inflammation moved from 0. 41 to 0. 58, and gut enzymes that break down food rose from 0. 612 to 0. 682. Two families of good bacteria, Lachnospiraceae and Lactobacillaceae, seemed to push back hardest against H. pylori and a troublesome group called Escherichia-Shigella. Meanwhile, Lachnospiraceae and Muribaculaceae acted like neighborhood organizers, linking up with other microbes and with the mice’s own health numbers.