Chemostat culturing reduces fecal eukaryotic virus load and delays diarrhea after virome transplantation

• DOI: 10.7554/elife.105991
• Publication Date: 2025-05-21T09:30:08Z
• Authors: Simone Margaard O...; Signe Adamberg; Malene Roed Spieg...; Xiaotian Mao; Torben Sølbeck Ra...; Frej Larsen; Jingren Zhong; Duc Ninh Nguyen; Dennis Sandris Ni...; Lise Aunsholt; Thomas Thymann; Kaarel Adamberg; Anders Brunse
• Keywords: Human virome; Chemostat; Fecal bacteriotherapy

Abstract Fecal virome transfer (FVT) shows promise in reducing necrotizing enterocolitis (NEC), likely due to donor bacteriophages preventing the gut dysbiosis preceding disease. However, concurrent of eukaryotic viruses may carry a risk infection for recipient. To increase safety, we investigated chemostat propagation as method eliminate from feces while maintaining diverse and reproducible bacteriophage community. Donor was collected healthy suckling piglets inoculated into fermenter containing growth media supplemented with lactose milk oligosaccharides (MOs). During continuous medium exchange (20% volume/h), dilution significantly reduced viruses. Viral richness concurrently although still preserving stable community 200-250 bacteriophages. Inclusion MOs ensured higher bacterial closer resembling feces. Lactobacillaceae bacteria were lost during cultivation but partially replaced by members Bacteroidota phylum MO-supplemented cultures, accompanied phages predicted have Parabacteroides host. After cultivation, virus-like particles (VLPs) isolated, their ability reduce NEC incidence tested vivo. Preterm delivered cesarean section received either lactose- or MO-propagated viromes oral route (n = 14-15/group). These compared groups receiving same dose fecal (1010 VLPs/kg) vehicle control. The subsequently fed infant formula 96 hours followed euthanasia tissue sampling. Both chemostat-propagated effectively mitigated diarrhea virome. engrafted recipients led levels targeting phages. these signatures viromes, only minor microbiome effects no prevention observed. conclude, provide vivo proof-of-concept means deplete turn side newborn recipients. culture conditions need further optimization preserve phageome.