Bacterial resistance to ?-lactam antibiotics is threatening to limit the effectiveness of this most- used class of antibiotics. A major contributin factor to this problem is the lack of rapid testing methods for medical practitioners to identify ? lactam-resistant pathogens before prescribing specific antibiotics. For urinary tract infections (UTIs), the most common bacterial infections in the world, older ?-lactam antibiotics are not used despite the fact that >60% of uropathogens are sensitive to these drugs. Resistance to ?-lactam antibiotics is conferred by the expression of ?-lactamases, enzymes that deactivate the antibiotics. We propose the development of a rapid immunoassay test kit for detection of any of a wide range of ?-lactamases. In Phase I of this project, we aim to develop cross-reactive monoclonal antibodies (MAbs) targeting the homologous regions of the most clinically problematic classes of ?-lactamases - extended- spectrum -lactamases (ESBLs) and carbapenemases - and then to develop a sandwich ELISA capable of distinguishing -lactam-resistant clinical bacterial isolates from ?-lactam-sensitive isolates. In Phase II, we will aim to convert this laboratory ELISA into a robust, 10-minute lateral flow immunoassay test kit (similar to the home pregnancy test), capable of detecting ?-lactamases, and therefore ?-lactam resistance, directly in patient samples. This capability promises to revolutionize current clinical practice for treatment of (UTIs), allowing the effective use of even the earliest ?-lactams and preventing the selection of resistance to current first-line treatments.