Bacterial identification using DNA hybridization probes has become increasingly sophisticated and accurate as probe technology and methods have improved. Up to now, however, instrumentation for detecting fluorescently- labeled probes has not been able to fully exploit the capabilities of such probes to identify high complex mixtures of genotypes in situ. Positive identification of single variant organisms in large populations of similar cells is also problematic. Fluorescent labeling methods are ultimately limited by the number of different spectral 'fingerprints' that can be distinguished by the imaging system that is used to measure and sort them. We propose to use a set of compatible fluorophores and recently developed KAIROS instrumentation and spectral deconvolution and sorting algorithms to increase the number of fluorescent tags that can be simultaneously distinguished, thus enabling accurate 'fingerprinting' of bacteria. In Phase 1 we will develop a set of these probes and demonstrate their efficacy on microscopic test targets. In Phase 2 we will apply the library of probes and the spectral deconvolution software to correctly identify highly complex mixtures of cells in situ by spectral sorting. This new technology for multispectral bacterial identification (Mbid) will benefit clinical and environmental microbiology as well as biotechnology. PROPOSED COMMERCIAL APPLICATION: Rapid and accurate fingerprinting of bacteria by multispectral fluorescent probes and fluorescence imaging microspectrophotometry is an enabling technology for both clinical and environmental aspects of microbial ID.