The applicant, Dr. Aaron Milstone, is a Pediatric Infectious Diseases Physician and Epidemiologist who has focused his career on the prevention of antibiotic resistance and healthcare-associated infections. The current proposal is a competitive renewal of a previously funded K24 award during which the applicant successfully mentored four junior faculty to receive NIH career development awards in patient-oriented research. Dr. Milstone is a highly productive clinical researcher with more than 200 manuscripts, more than 95 first-authored by his mentees. He has had continuous federal-funding since 2009 to support his research program translating laboratory and epidemiologic observations into patient- and population-level interventions. He is sought after as a collaborator and mentor. Dr. Milstone will continue to leverage the extensive training resources at Johns Hopkins University to recruit and support trainees. Renewal of this K24 is critical to his desire to continue to mentor young investigators in the areas of antibiotic-resistance and infection prevention and to continue to evolve his research. Dr. Milstone will pursue additional training to expand his research program. The proposed novel research will further advance the field in preventing antibiotic resistance and healthcare-associated infections in three areas: 1) bacterial culture stewardship to reduce antibiotic use and resistance, 2) targeting the nasal microbiome to reduce S. aureus nasal colonization and infection, and 3) identify and address drivers of inequities in pediatric healthcare associated infections. The proposed projects will build on collaborations in implementation science, microbiome, and health equity, expand the Dr. Milstone's knowledge in these areas, and make him a more effective PI and patient-oriented research mentor.