Gram-negative bacteria staining

Patent Pending Gram-negative bacteria generally possess a thin layer of peptidoglycan between two membranes (diderms). Most bacterial phyla are gram-negative, including the cyanobacteria, spirochaetes, and green sulfur bacteria, and most Proteobacteria and Escherichia coli. (exceptions being some members of the Rickettsiales and the insect-endosymbionts of the Enterobacteriales).