Background: Each year in the US, there are over 18 Million Blood Cultures performed to determine the presence/absence of viable microorganisms in the blood of patients suspected of having Blood Steam Infection (BSI or Septicemia). Current technology for Blood Cultures typically takes 1-5 days to provide a result. Our proposed system would enable the user to obtain Blood Culture results in 2-24 hrs. instead which will greatly improve the outcomes for patients with Sepsis. Innovation: At the core of the system lies a patent-pending electrical method, which can detect proliferating microorganisms in suspensions based on charges stored at the intact cell membranes of live microorganisms. This approach was shown (prior to Phase I) to be 4-10X faster than the current methods employed in BACTEC TM (current Gold Std.) However, in order to achieve the desired sensitivity, our method required that aliquots be periodically withdrawn from the broth (blood culture medium + patient blood) into a thin long chamber for an "electrical scan" (impedance measurements are frequencies 1KHz - 100 MHz). The data from this "scan" is then analyzed to calculate the "Bulk Capacitance" (Cb), a parameter that rises with the rise in the number of live microbes. We successfully achieved our Phase I goals by showing that (a) the automated sampling could be repeatedly performed aseptically over 5 days (5x longer than foreseen need);(b) the sophisticated electrical measurements needed could be obtained using a circuit designed and assembled by us;and (c) the threshold concentrations, and hence Times to Detection (TTDs), using our Phase I were much lower than those of BACTEC TM. Approach: In Phase II, we propose to (a) build an 8-unit "research" unit;(b) verify the robustness of our device: its abilit to handle different volumes of blood with different properties such as hematocrit and WBC counts;(c) verify our ability to correctly diagnose clinical samples using the 8-unit system;and (d) design (using "Good Design Principles"&keeping records in a "Device History File") a 64 unit 'market ready'system. By the end of the funded period (3 yrs.), we will be ready to meet with the FDA armed with a Device History File documenting the development of the product (64-unit system) &clinical studies (NB: not clinical trials) showing equivalency to existing devices such as BACTECTM (in terms of being able to correctly identify positives) and also demonstrate improved performance (reduced TTDs) to potential partners and/or investors.

Public Health Relevance

Each year in the US, there occur over 751,000 cases of Sepsis (the systemic inflammation in response to infection, by bacteria and/or other microorganisms, of normally-sterile tissues like blood), out of which 383,000 (51.1%) require intensive care, and 215,000 (28.6%) are fatal. The high mortality rate is a direct function of the time needed to detect the presence of bacteria in blood. The proposed instrument will cut down the time needed for blood cultures from 1-5 days to <24 hours, thereby ensuring much improved patient outcomes.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Small Business Innovation Research Grants (SBIR) - Phase II (R44)
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Special Emphasis Panel (ZRG1-IDM-V (12))
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Ritchie, Alec
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Techshot, Inc.
United States
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