A New Biosensor for Rapid Identification of Bacterial Pathogens

Rapid, handheld, or portable instrumentation for determining the quality of natural waters, recreational waters, and distributed and treated supplies does not currently exist. Echo Technologies, Inc., completed a Phase I project that demonstrated a new approach for the identification of bacteria in aqueous systems. The approach uses bacteriophage as the molecular recognition element. Bacteriophage are virus particles that generally attach to and infect a narrow range of host cells. Biosensors based on this molecular recognition offer a rapid, selective, and potentially very sensitive method to detect bacteria and bacterial pathogens in potable and recreational waters.Feasibility of the concept was demonstrated by fabricating fluorescently labeled virus probes (FLVPs) to detect and identify bacteria for representative waterborne bacteria, including: Escherichia coli, Enterococcus faecalis, and Vibrio natriegens bacteria. The preparation of FLVPs has been made quite reproducible. The adhesion to host cells is very rapid, good selectivity was demonstrated in samples with host cells and mixtures, and the response from a solid-phase FLVP biosensor was demonstrated. Several experiments were conducted with a customized detection system to demonstrate the feasibility of making a small in-line instrument capable of high-sensitivity detection. These cumulative results lay an excellent foundation for the Phase II development effort. In Phase II, a prototype rapid bacteria identification system will be designed, fabricated, and evaluated in the laboratory and at an independent test facility. The heart of the instrument will be an array of encoded FLVPs integrated with a charge coupled device (CCD)-based imaging/detection system. Application of the FLVP technology to solid-state optical sensing represents a new approach to real-time detection of bacterial pathogens. This approach will minimize the need for culturing to identify pathogens, and is an important departure from immunoassay- or DNA-based sensing concepts. The miniature probes are perfectly suited for incorporation in a sensor array for the simultaneous detection of many bacterial pathogens.