Multiplexed, Non-Amplified, Nucleic Acid-Based Identification of Multidrug Resistant Pathogens Using an Integrated Optofluidic Platform

Brigham Young University, Provo UT

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Abstract

? DESCRIPTION (provided by applicant): Antibiotic resistance has emerged as a major public health threat. Patients infected with drug- resistant pathogens suffer significantly higher rates o morbidity and mortality, most often due to delays in the administration of effective antimicrobial therapies. In particular for bloodstream infections, the need to rapidly identify both pathogen and resistance profile is crucial, as treatment with antibiotics to which the organism is sensitive is essential and time-critical. Indeed, sepsis is involved in up to half of all hospital deaths. Drug susceptibility information for a pathogen is typically not received by clinicians until at least 24 hours post-sampling, because of reliance on culture-based diagnostic methods. Recently, bloodstream infections caused by carbapenem-resistant Enterobacteriaceae (CRE) have become increasingly problematic. A rapid diagnostic assay for the detection and resistance determination of these pathogens is urgently needed. Although PCR-based assays are rapid, specific, and amenable to multiplexing, they have largely failed to perform in blood samples. Our industrial partner, Great Basin Corporation, has developed a fully disposable cartridge system for pathogen detection in cultured blood. We propose major improvements to this platform through the development of a multiplexed, non-amplified, non-cultured, nucleic acid-based assay for the detection and identification of multidrug resistant pathogens using a novel integrated optofluidic device. Bacteria will be concentrated directly from a blood sample by cross-flow filtration, and then delivered to a lysis and DNA-shearing chamber. Target DNAs containing the genes of interest will be captured on a solid substrate by hybridization. Molecular beacons will be hybridized to specific targets on the captured nucleic acids. These complexes will be released and specific beacons detected by an advanced optofluidics system capable of detecting single molecule fluorescence. We will demonstrate identification within one hour of bacteria in blood at levels as low as 10 CFU/mL. Initially, the focus will be to detect and characterize CRE isolated directly from a blood sample. The KPC, NDM, VIM, and IMP carbapenemase genes will be identified along with the simultaneous detection of specific markers for Klebsiella pneumoniae, Escherichia coli, and Enterobacter species. This platform is readily expandable to additional pathogens and their relevant antibiotic resistance genes. This technology has the potential to significantly reduce time to diagnosis and improve clinical outcomes.