Hryckowian et al. generated humanized microbiota mice by colonizing germ-free Swiss Webster mice from Taconic Biosciences with healthy human donor microbiota. In an antibiotic-induced C. difficile infection model, the humanized microbiota mice maintained on a diet containing microbiota-accessible carbohydrates (MACs) efficiently cleared the pathogen, whereas humanized microbiota mice maintained on a diet deficient in MACs had persistent infection for a prolonged period. Similar results were observed in conventional microbiota Swiss Webster and C57BL/6NTac mice as well as germ-free Swiss Webster mice which were associated with a conventional mouse gut flora1.
The researchers hypothesize that MACs may act in two ways to control C. difficile:
MACs may drive growth of gut bacteria which use MACs, suppressing C. difficile growth.
MAC metabolism produces short chain fatty acids, which also suppresses C. difficile.
As the authors write, this study "is part of a growing body of literature providing evidence that dietary manipulation of the metabolic networks of the intestinal tract is a powerful and underexplored way to influence gastrointestinal pathogens1."