Antibacterial resistant Staphylococcus aureus, in particular methicillin-resistant S. aureus (MRSA), infections constitute a serious worldwide health problem. MRSA infections are usually hospital-acquired, although the incidence of community-acquired infections has been increasing in recent years. Rapid determination of the resistance status of the staphylococcal isolate is important in order to select efficacious antibacterial agents, minimize development of resistance to drugs of last resort, and identify patients and healthcare workers harboring MRSA so that control strategies can be implemented. Current methods to detect resistant strains are either expensive or time-consuming. Nomadics' proposed system provides a sensitive, rapid, and affordable detector capable of identifying resistant S. aureus as well as other staphylococcal and bacterial species. During Phase I development, amplifying fluorescent polymer (AFP) was modified and improved to detect low concentrations of biological analytes, in this case, MRSA mecA gene (for resistance identification), coa gene (coagulase, for species identification), and PBP2a protein (penicillin binding protein 2a, for resistance identification). The functioning of the detection system is such that, in an assay, an oligonucleotide probe-DNA target or antibody-protein target recognition event results in signal amplification, detectable using an optical sensor. These methods have been integrated into a prototype detection system that will serve as the basis for the proposed Phase II project. The ultimate goal of Phase II will be to develop and test an in vitro diagnostic device that can be used by clinicians, hospitals, acute care facilities, and skilled nursing environments for early identification of MRSA and other resistant bacteria in clinical samples.