Purpose of review: To highlight recent developments in understanding the dynamic relationship between circadian rhythms, the gut microbiome, and gastrointestinal infections.
Recent findings: In humans and mice, the composition and functions of the intestinal microbiome display diurnal rhythms orchestrated by feeding behaviors and host circadian gene expression. Jet lag, or circadian disruption, perturbs these rhythms to produce gut dysbiosis. When mice are orally infected with Salmonella typhimurium in the morning (the beginning of their rest period) they show higher levels of colonization and gut inflammation vs. infection at other times of day. At the cellular level, recent studies highlight circadian regulation of innate and adaptive gut immunity in coordination with the microbiome, as well as intestinal stem cell growth and regeneration.
Summary: Taken together, these reports support a key role for circadian rhythms in regulating the gut microbiome and host responses to gastrointestinal pathogens. Further research is needed to translate these findings to improving outcomes for patients with gastrointestinal infections by guiding the right interventions for the right patients at the right time.