Probiotics evolve inside mice, a path that could affect humans, too

Probiotics — which are taken as nutritional supplements and are being explored as therapies for a range of diseases — evolve in unexpected ways when introduced in mice. Researchers behind a new study gave probiotic E. coli as well as a combination of the probiotic mixed in with human-derived gut microbes to mice with varying levels of gut microbiome diversity. They found that probiotics in mice with low microbial diversity underwent the biggest evolutionary changes, including gaining the ability to chew threw a protective mucus layer in the small intestine. Those who are developing bacterial-based treatments ought to pay attention to such long-term consequences, the authors say, especially since probiotics are often used over a short term.