Mechanism of the Action of Didecyldimethylammonium chloride (DDAC) against Escherichia coli and Morphological Changes of the Cells

Abstract

The antibacterial activity of a disinfectant with geminated twin long-chain alkyl groups, didecyldimethylammonium chloride (DDAC), was investigated.The minimum inhibitory concentration (MIC) value of DDAC against Eschrichia coil was revealed to be a small value, 1.3 mg/L, by using the specific growth rates, IA, obtained from the cultivation in a liquid nutrient broth (NB) medium. The relationship between the leakage of proteins or 13 -galactosidase and the DDAC concentration showed that the leakage of intracellular macromolecules occurs at around 3 -4 mg/L DDAC. Furthermore, the effect of DDAC on the enhancement of membrane fluidity was examined by using liposomes labeled with a fluorescent probe. It was shown that the phase transition occurs at around 3 mg/L DDAC. The bleb formation of E. col/ cells in the presence of DDAC was also examined by use of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). However, bleb formation was not observed at around 3 mg/L DDAC but at concentrations higher than 50 mg/L. These results suggested that the action of DDAC toward the cell membrane causes the leakage of the intracellular molecules and the subsequent death of the cells. Thus the bleb formation seemed to be a result of the action of the DDAC toward the cell membrane but not to be a reason for the death of the cells.

Anti-biofilm Effect of Dental Adhesive with Cationic Monomer

“…However, the growth and proliferation of adherent bacteria can be inhibited by the cured adhesive with cationic moieties, as suggested in a previous study with MDPB-containing material (Imazato et al, 2003b). Unlike the soluble polycationic agents, presumably exerting biocidal activity (Sumitomo et al, 2006;Yoshimatsu and Hiyama, 2007), the immobilized cationic biocide was reported to be bacteriostatic (Ebi et al, 2001;Imazato et al, 2003b). This attenuated antibacterial effect might exert influence on the physiological status and the membrane configuration of bacteria, leading to retarded bacterial proliferation and biofilm initiation.…”

Effects of a dental adhesive incorporating antibacterial monomer on the growth, adherence and membrane integrity of Streptococcus mutans

“…17,18 However, there are reports in the literature describing that monomers incorporated into composite resins lose their bactericidal activity compared to their water-soluble forms. 12,19 Whether this attenuated antibacterial effect of immobilized monomer is strong enough to interrupt the integrity of bacterial membrane and then trigger the efflux of cytoplasmic constituents remains obscure.…”

“…This process may contribute to the disruption of cell membranes, and subsequently lead to the increase of cell permeability and the leakage of the cytoplasmatic constituents. 17,18 As for the immobilized cationic biocide, hitherto, the antibacterial efficiency and the underlying antibacterial mechanism are still controversial in the literature. MDPBcontaining resinous materials were reported to exhibit bacteriostatic effect in stead of bactericidal effect.…”

Altered pulmonary defense system in lung injury induced by didecyldimethylammonium chloride in mice

“…These data suggest that DDAC might improve membrane lipid integrity in a variety of cells. DDAC kills bacterial cells 5 min after treatment; autolysis is initiated in cells due to the breakdown of both RNA materials and highly ordered membranes, which coincides with potassium depletion and the leakage of proteins and β-galactosidase from cells (Ioannou et al, 2007;Yoshimatsu and Hiyama, 2007). Furthermore, P. fluorescens degrade DDAC to produce dimethylamine (Nishihara et al, 2000), which is particularly toxic to the respiratory systems of rats and mice (Coon et al, 1970;Buckley et al, 1985).…”