The Bacterial Viability and Gram Stain Kit contains three components: CF®488A-WGA, DAPI, and EthD-III solutions for distinguishing between gram-negative and gram-positive, as well as live versus dead bacteria. CF®488A-labeled wheat germ agglutinin stains the N-acetylglucosamine of the peptidoglycan layer of gram-positive bacteria with green fluorescence (excitation/emission 490/515 nm). The bacterial viability component of the assay is based on the integrity of the cell membrane. EthD-III is a nucleic acid binding dye that is membrane impermeable, which selectively stains cells with compromised plasma membranes with red fluorescence (excitation/emission 530/620 nm). All cells stain blue with the membrane permeable DNA dye DAPI (excitation/emission 358/461 nm). One kit is sufficient 200 assays when used according to the kit protocol. The Bacterial Viability and Gram Stain Kit has been tested on the following bacterial species: Bacillus subtilis subsp. subtilis, Escherichia coli, Micrococcus luteus, Pseudomonas fluorescens, and Staphylococcus epidermidis.