Animal Models Core Studies of antibiotic tolerance and of new therapies to treat antibiotic-resistant pathogens must, at some point, be evaluated in mammalian models of infection. These pre-clinical assessments are a fundamental step to determining whether treatments might be translated to human studies. Moreover, the complexities of the mammalian immune response can be queried to gain insight into the basic pathobiology of infections and host defenses. The Animal Models Core of the Center for Antimicrobial Resistance and Therapeutic Discovery (CARTD) will enable pre-clinical studies in mice to facilitate rapid, high-quality data acquisition. The Core will provide essential input, along with that from our biostatistics expert, to aid in experimental design that enhances the robustness of the results. The Core Director will train the Junior Investigators and assist them in obtaining the institutional approvals necessary to conduct animal experiments. The Core will maintain a portfolio of techniques directly related to the experimental objectives of the research projects, as well as expand the repertoire to diversify the research projects and to recruit investigators from beyond the CARTD. The Core?s design includes blinding of treatment groups so that observers make unbiased assessments of the animals throughout the experiment. The Core?s staff will conduct experiments in conjunction with the laboratories of the research and pilot projects. Importantly, the Core will be responsible for managing the new in vivo imaging system recently procured by our institution. This imaging system enhances the robustness and reproducibility of the studies by longitudinal follow-up of individual animals while reducing the overall numbers of animals that are required in any given experiment. The Animal Models Core?s functions are defined by the following specific aims: 1. To provide consultation and assistance in planning experimental design, strain selection, and outcomes analysis. 2. To conduct infection and treatment experiments in collaboration with investigators from the Junior Investigator and Pilot Project research programs, as well as outside researchers. 3. To supervise, schedule, maintain, and operate the PerkinElmer IVIS Lumina III in vivo imaging system.