Equipment and Methods for Concurrently Housing Germfree and Gnotobiotic Mice in the Same Room

Here, we combined the use of 2 technologies that have not previously been used together—a positively pressurized isolatorIVC (IsoIVC-P) and a modular isolator with integrated vaporized hydrogen peroxide (VHP) technology—to develop highlytractable and scalable methods to support long-term maintenance of germfree mouse colonies and the concurrent use of germfreeand gnotobiotic mice in the same room. This space-efficient system increases the practicality of microbiome studies.Specifically, the exterior surfaces of microbially similar IsoIVC-P were sterilized by using VHP prior to opening the cagesand handling the mice therein. This space-efficient system increases the feasibility of microbiome studies. After over 74 wkof experimentation and handling equivalent to more than 1,379,693 germfree mouse-days, we determined that the methodand practices we developed have a weekly performance metric of 0.0001 sterility breaks per husbandry unit; this rate is comparableto the isolator ‘gold standard.’ These data were achieved without adverse incidents while maintaining an AlteredSchaedler Flora colony and multiple gnotobiotic studies involving fecal microbial transplants in the same room. Our novelIsoIVC-P–VHP workstation housing system thus improves microbiome research efficiency, eliminates hazards, and reducesrisks associated with traditional methods.