Project Summary Methicillin-resistant Staphylococcus aureus is a serious threat according to the Centers for Disease Control and Prevention (CDC), due to the increased morbidity and mortality among individuals who are infected with this pathogen.1 As a common healthcare- and community-associated pathogen, MRSA has a high burden of disease with over 300,000 cases and roughly 11,000 deaths in 2017.1 Though the overall rates of MRSA infection have been decreasing nationwide, this has not translated in communities of color, as the rates of healthcare-associated (HA), healthcare-associated community onset (HACO), and community-acquired (CA) MRSA is much higher among blacks compared to white individuals. 2–6In addition, we understand that jails have a disproportionately high prevalence rate of MRSA (19%) and a high proportion of people of color.7,8 Detainees have high rates of recidivism with about 76.6% of prisoners are rearrested within five years. 8 Once released, detainees interact with the community they came from prior entering the jail, resulting in potential transmission events. What is not well-understood is if jails themselves are an amplifier of MRSA community transmission. In this proposal, we will investigate the relationship between jail transmission of MRSA and the potential of transmission spillover into the wider community by utilizing genomic-based regression approaches and individual-based modelling. The results will elucidate how can jails amplify community transmission, especially among communities of color, and may perpetuate high rates of MRSA infections and/or colonization. Understanding this phenomenon will allow us to improve MRSA surveillance in these communities and design and increase targeted interventions in communities of color and within jails that potentially feed into their communities.