Probiotic yogurts and pills promise better health, but the bacteria we ingest find a complex and challenging environment when they enter our gut. Food sources shift with every meal we eat, and the threat of pathogens is ever-present. In this competitive landscape, there’s a clear winner already on the field: The genus Bacteroides makes up 30 percent of the bacteria in the human gut, the single most abundant genus.

Bacteroides are a successful bacterium in our gut microbiome. By offering metabolic capabilities that humans don’t have, it helps us to obtain important nutrients. So why are Bacteroides so resilient? If we can understand their success, it will ultimately allow us to design probiotic formulations for human health and aid patients with an imbalance of gut bacteria,” said Blanca Barquera, professor of biological sciences and lead researcher on a new project investigating Bacteroides, supported by the National Institutes of Health.