Differential microbial community assembly following co-housing versus microbiota transplant.

Mouse models are vital tools for discerning the relative contributions of host and microbial genetics to disease, often requiring the transfer of microbiota between different mouse strains. Transfer methods include antibiotic treatment of recipients and colonization using either co-housing with donors or the transplantation of faecal or caecal donor material. However, the efficiency and dynamics of these methods in reconstituting recipients with donor microbes is not well understood. We thus directly compared co-housing, faecal transplantation, and caecal transplantation methods. Donor mice from Taconic Biosciences, possessing distinct microbial communities, served as the microbial source for recipient mice from Jackson Laboratories, which were treated with antibiotics to disrupt their native microbiota. We monitored bacterial and viral populations longitudinally over the course of antibiotics treatment and reconstitution using 16S rRNA gene sequencing, quantitative PCR (qPCR), and shotgun sequencing of viral-like particles (VLPs). As expected, antibiotic treatment rapidly depleted microbial biomass and diversity, with slow and incomplete natural recovery of the microbiota in non-transfer-recipient control mice. Although all transfer methods reconstituted recipient mice with donor microbiota, co-housing achieved this more rapidly for both bacterial and viral communities. Overall, faecal and caecal transplant resulted in highly similar colonization processes with some minor variation in enrichment for two specific bacterial families. This study provides valuable insights into microbial ecology, as well as the dynamics underlying experimental microbial transfer methods, enhancing reproducibility and informing best practices for microbiota transfer in mouse models.