The Effect of Ethylenediaminetetra-acetic Acid on the Cell Walls of Some Gram-Negative Bacteria

SUMMARY: A comparative survey of amino acid, amino sugar, sugar and lipid components of the cell walls of strains of Pseudomonas aeruginosa, Alcaligenes faecalis, Escherichia coli and Proteus mirabilis was made. The cell walls of P. aeruginosa and A. faecalis, against which ethylenediaminetetra-acetic acid (EDTA) has a potent bactericidal action, differed from those of the other organisms principally in their sugar components and in their high content of phosphorus. EDTA at alkaline pH selectively solubilized a high proportion of the carbohydrate and phosphorus present, apparently as lipopolysaccharides, in the walls of sensitive organisms. It is suggested that metal cations and lipopolysaccharides in the cell walls of P. aeruginosa and A. faecalis may be essential to the structural integrity of these organisms.