Grant: $390,000 - National Institutes of Health - Sep. 25, 2009
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Award Description: Infections with antibiotic resistant bacteria are increasing at an alarming rate. Antibiotic resistance is a particular problem in patients with blood stream infections or sepsis, due to the a mortality that rises exponentially as effective treatment is delayed. Bacterial species identification can often be used to guide antibiotic therapy while true antibiotic susceptibility test results are still pending. In fact, a few types of molecular assays have recently begun to offer rapid detection of the bacteria responsible for blood stream infections. However, existing methods are cumbersome, expensive and are limited to detection of a small minority of possible pathogens. We have developed a new paradigm for multiplex bacterial species identification. Our approach replaces the idea of using one molecular probe to identify one DNA target with the concept of using a mixture of a small number of molecular probes to act together and identify a very wide range of DNA target sequences. We will use this approach to design a real-time PCR assay capable of detecting virtually all pathogenic bacteria and common contaminants within a single PCR assay well. Key to this assay is the development of novel 'sloppy molecular beacons (SMB), which can tolerate substantial sequence mismatches with their DNA target and yet still fluoresce brightly in the presence of these targets. In this proposal, we will combine our novel multiplex detection approach and our SMB technology with an additional form of multiplexing which we call a 'virtual array to make a broadly useful 'molecular blood culture . The molecular blood culture will identify virtually all pathogenic bacteria and common contaminants in a rapid single-well PCR assay. We will then develop this assay for direct species identification first on positive patient blood cultures, and later on blood samples drawn directly from patients with bacteremia and sepsis. The specific aims of this proposal are: 1) to develop a model assay that identifies virtually all pathogenic bacteria in a single PCR tube or well in under two hours. 2) To further improve assay performance by creating a virtual array within the assay tube or well, enabling the incorporation of additional assay targets. 3) To develop a library of hybridization patterns for simple and multiple infections by serial analysis of clinical strains and identify the 'Tm space of each bacterial species. 4) To test and optimize the detection system on clinical blood cultures and directly drawn patient blood samples and then prospectively test the assay.
Project Description: As defined in the Award Description.
Jobs Summary: not yet started (Total jobs reported: 0)
Project Status: Not Started
This award's data was last updated on Sep. 25, 2009. Help expand these official descriptions using the wiki below.