Ménage à trois in the human gut: interactions between host, bacteria and phages

The human gut is home to dense bacterial and phage populations that are involved in regulating human health.Phages regulate bacterial abundance, diversity and metabolism in numerous ecosystems, but their effects in the human gut remain largely unexplored.Despite high bacterial abundance and metabolism, the majority of described phages in the gut are integrated within their bacterial hosts, which suggests dynamic interactions that are specific to this system.Different bacteria–phage interactions occur depending on the health status and development stage of the human host. Characterization of these interactions would provide unique ways to improve disease or developmental outcomes.Further research on phage replication cycles and phage pharmacodynamics is essential before considering their therapeutic use for human health.