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Updated: Feb 25, 2026
Preparation and Maintenance of Bioexclusion IsoPositive Cage Experiment for Human Fecal Transplantation into Germ-Free Mice
Published on: February 28, 2025
Stable engraftment of human microbiota into mice with a single oral gavage following antibiotic conditioning
Christopher Staley1, Thomas Kaiser1, Lalit K Beura2,3
1BioTechnology Institute, University of Minnesota, St. Paul, MN, USA.
Background:
Human microbiota-associated (HMA) animal models relying on germ-free recipient mice are being used to study the relationship between intestinal microbiota and human disease. However, transfer of microbiota into germ-free animals also triggers global developmental changes in the recipient intestine, which can mask disease-specific attributes of the donor material. Therefore, a simple model of replacing microbiota into a developmentally mature intestinal environment remains highly desirable.
Results:
Here we report on the development of a sequential, three-course antibiotic conditioning regimen that allows sustained engraftment of intestinal microorganisms following a single oral gavage with human donor microbiota. SourceTracker, a Bayesian, OTU-based algorithm, indicated that 59.3 ± 3.0% of the fecal bacterial communities in treated mice were attributable to the donor source. This overall degree of microbiota engraftment was similar in mice conditioned with antibiotics and germ-free mice. Limited surveys of systemic and mucosal immune sites did not show evidence of immune activation following introduction of human microbiota.
Conclusions:
The antibiotic treatment protocol described here followed by a single gavage of human microbiota may provide a useful, complimentary HMA model to that established in germ-free facilities. The model has the potential for further in-depth translational investigations of microbiota in a variety of human disease states.
Insights
A new antibiotic regimen enables successful human microbiota engraftment in mature mice, offering a valuable model for studying gut microbiome and human disease without developmental changes.
Area of Science:
- Microbiology
- Immunology
- Gastroenterology
Background:
- Human microbiota-associated (HMA) animal models are crucial for studying the gut microbiome's role in human diseases.
- Germ-free animal models experience developmental changes upon microbiota transfer, potentially masking disease-specific attributes.
- A simple model for microbiota replacement in mature intestinal environments is needed.
Purpose of the Study:
- To develop a novel method for microbiota engraftment in a mature intestinal environment.
- To establish a complementary HMA model for translational research.
Main Methods:
- A sequential, three-course antibiotic conditioning regimen was developed.
- Human donor microbiota was administered via a single oral gavage.
- SourceTracker, a Bayesian algorithm, quantified microbiota engraftment.
Main Results:
- The antibiotic regimen allowed sustained intestinal microorganism engraftment.
- 59.3 ± 3.0% of fecal bacterial communities in treated mice originated from the human donor.
- Engraftment levels were comparable to germ-free models, with no observed immune activation.
Conclusions:
- The described antibiotic protocol and microbiota gavage offer a complementary HMA model to germ-free approaches.
- This model facilitates translational investigations of the microbiota in various human diseases.
- The model avoids developmental changes, allowing clearer observation of disease-specific attributes.
