Faecal microbiota transplantations and the role of bacteriophages

Background: Bacteriophages are a major component of the human gut microbiota. Emerging evidence suggests that gut bacteriophages play an important role in the intricate dynamics with bacteria, and their transfer may be associated with the efficacy of faecal microbiota transplantation (FMT).
Objectives: To summarize our current knowledge of the changes in gut bacteriophage communities during FMT and their association with FMT outcome.
Sources: PubMed, Web of Science, and Google Scholar were searched for articles on FMT and bacteriophages published between May 2013 and January 2022.
Content: Preclinical and clinical studies have reported associations between gut bacteriophage profiles and FMT. FMT was associated with donor-specific engraftment of bacteriophages, characterized by increased viral diversity and richness, and the bacteriophage composition resembled the donor's profile after FMT. Limited studies showed that cure after FMT was more likely when an increased fraction of the recipient enteric virome was occupied by donor-derived taxa, including Caudovirales in Clostridioides difficile infection. Faecal virome transplant involving the transfer of the gut virome communities alone may also induce phenotypical and microbiome improvement in various diseases.
Implications: The accumulating evidence that bacteriophages play roles in FMT efficacy has attracted considerable interest. Better characterization of bacteriophages and an understanding of their underlying mechanisms in FMT are warranted.