Effects of Organic Cations on the Gram-negative Cell Wall and Their Bactericidal Activity with Ethylenediaminetetra-acetate and Surface Active Agents

Abstract

S U M M A R YWhen Gram-negative cell walls were damaged by lysozyme and ethylenediaminetetra-acetic acid (EDTA) in tris buffer, tris played an active role through its action as an organic cation. Other organic cations such as aliphatic amines and quaternary ammonium compounds were more effective than tris in modifying the cell wall and making it permeable to other solutes. The most effective organic cations had one C,, to CI6 alkyl chain. At ~H I o , EDTA roo pg./ml and N,N-dimethyldodecylamine (DDA) 2.5 ,ug./ml. modified the cell wall of Escherichia coli so as to permit a more than 99.99 % kill by 20,ug.fml. of a zwitterionic surface active agent, a-hydroxy-3-(dimethylhexadecylammonio) propane-I -sulphonate (HAPS), in 10 min. at 37'. At these concentrations, the individual compounds were bactericidally ineffective. Four other Gram-negative species were shown to be similarly susceptible to killing by this system. Together, EDTA and DDA appeared to remove surface components of the Gram-negative cell wall. Alone, DDA and other organic cations removed somatic antigens from the cell wall.

Introduction of proteins into living bacterial cells: distribution of labeled HU protein in Escherichia coli

“…These earlier studies used Tris-buffered medium during growth, which may condition cells. However, adverse effects of Tris have been reported (13,34). In addition, it was found that (i) Tris-Cl and Tris-acetate were nearly equivalent in toxicity, (ii) addition of KGiu protected permeabilized cells against the adverse effects of Tris, and (iii) viability of unpermeabilized cells was not affected by Tris at the concentrations used here (data not shown).…”

Simple additives to increase the activity of chlorhexidine digluconate against urinary pathogens

“…This work was prompted by reports that EDT A could enhance the action of antiseptics (Brown & Richards, 1965;Caplin & Chapman, 1976;Goldschmidt et at., 1972) and that Tris increased the activity of EDTA (Voss, 1967;Goldschmidt and Wyss, 1967). It was hoped that the addition of these agents would enable the concentration of chlorhexidine to be reduced so that it was less erosive and also overcome any resistance that has been previously reported by Stickler (1974).…”

Studies on the Cell Walls of Pseudomonas Species Resistant to Ethylenediaminetetra-acetic Acid

“…Although EDTA has been found to extract lipopolysaccharide from Escherichia coli, the bacteria remained viable under the conditions used (Leive, 1965). Except when used in conjunction with organic cations (Wolin, 1966;Goldschmidt & Wyss, 1967;Voss, 1967), EDTA does not seem to be highly toxic for Gram-negative bacteria other than pseudomonads (Gray & Wilkinson, 1965 a;Wilkinson, 1967). This hypersensitivity to EDTA might prove to be a useful characteristic in the taxonomy of the pseudomonads (Shively & Hartsell, 1964;Wilkinson, 1967 (1956) without prior hydrolysis of samples, and was expressed as glucose.…”