Summary The goal of this Phase I project is to demonstrate feasibility of an equitable, rapid antibiotic susceptibility test (AST) for urinary tract infections (UTIs) to be used in resource-limited and outpatient settings. UTIs impact over 13 million patients in the U.S. and 400 million worldwide each year. Women as well as individuals from low socioeconomic backgrounds are disproportionately impacted by UTIs. Using currently available tools, healthcare providers either delay prescription by up to 3 days while they wait for laboratory results to guide treatment or prescribe antibiotics prior to obtaining laboratory results. Either approach delays customized therapy, often prolonging pain, increasing the risk of serious complications and life-threatening urosepsis, and driving up healthcare costs. To minimize the risk of resistance to uninformed treatment, providers can prescribe overly aggressive treatment. However, this can lead to long-term side effects and exacerbates the antimicrobial resistance crisis. Condensing the days-long diagnostic turnaround time has the potential to improve patient outcomes, reduce healthcare costs, and promote antimicrobial stewardship. Although rapid AST technologies exist, such instruments are rarely used for UTI diagnostics and are not widely available in outpatient or resource- limited clinical settings. There is an unmet need for a rapid test that can guide antibiotic treatment in all settings where UTIs are treated. Latde Diagnostics, a women-owned small business, is developing the Metabolic Amino Acid Phenotyping (MAAP) test kit to provide susceptibility profiles for UTIs in <2 hours and make rapid ASTs accessible to resource-limited and outpatient clinical settings in the U.S. and low and middle income countries (LMICs). The MAAP assay couples metabolic labeling of bacterial cell wall with immunodetection and is based on user needs identified through >220 customer interviews. MAAP’s bacterial cell wall building block analog mimics a molecule conserved across UTI-causing bacteria, and is incorporated into the surface of actively- growing bacteria in minutes, yielding a rapid phenotypic tool. Immunodetection allows seamless integration into clinical workflows without the need for costly, specialized instrumentation through the use of lateral flow assay (LFA). Latde has shown that the MAAP assay detects growth in leading UTI causative agent, Escherichia coli, including clinical isolates from UTI samples. To validate the clinical utility and technical feasibility of the MAAP assay, using a breadth of E. coli strains implicated in UTIs, Latde will 1) demonstrate feasibility of LFA readout within clinically-relevant turnaround time and bacterial titer; and 2) eliminate repeated wash steps from the assay. In future Phase II, Latde will assemble components generated in Phase I into a single prototype, which will then be optimized and modified to meet Clinical and Laboratory Standards Institute (CLSI) guidelines. Ult...