But developing therapeutics will be harder than just mixing the microbes together into pill form, Karp says, because babies already have guts that are teeming with other bacteria. These “first colonists” may prevent new strains from easily taking over. And another study has suggested different bacteria as protective. “It’s not clear right now that there are ways to induce the growth of these particular bacteria in kids,” she says. “But it certainly starts to open the door toward that possibility.”