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. Fluorescently labeled wheat germ agglutinin binds specifically to the N-acetylglucosamine of the peptidoglycan layer of gram-positive bacteria1. 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. All cells stain blue with the membrane permeable DNA dye DAPI. 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.