Reproducible chemostat cultures to minimize eukaryotic viruses from fecal transplant material.

Recent studies indicate an important role of bacteriophages for successful fecal microbiota transplantation (FMT). However, wider clinical applications of FMT are hampered by to donor variability and concerns of infection risks by bacteria and human viruses. To overcome these challenges, mouse cecal and human fecal material were propagated in a chemostat fermentation setup supporting multiplication of bacteria, and phages, while propagation of eukaryotic viruses will be prevented in the absence of eukaryotic host cells. The results showed decrease of the median relative abundance of viral contigs of classified eukaryotic viruses below 0.01%. The corresponding virome profiles showed dilution rate dependency, a reproducibility between biological replicates, and maintained high diversity regarding both the human and mouse inocula. This proof-of-concept cultivation approach may constitute the first step of developing novel therapeutic tools with high reproducibility and with low risk of infection from the donor material to target gut-related diseases.