Bacteriolyses of Bacterial Cell Walls by Zinc (Ⅱ) Ions on the Basis of the Results of Halo Antibacterial Susceptibility Tests for Metallic Salt Solutions

Bacteriolyses of bacterial cell walls by zinc (Ⅱ) ions on the basis of the results of halo antibacterial susceptibility tests were investigated for the nitrate and the sulfate solutions. From the results obtained by halo antibacterial tests of sulfate solutions against Staphylococcus epidermidis, the antibacterial order is Zn2+>Cu2+>Ag+>Al3+, in which Zn2+ ions indicate the highest antibacterial effect. Bacteriolysis of S.aureus PGN cell wall by zinc ion is due to the inhibition of PGN elongation by the activation of PGN autolysins of amidases and side-chain endopeptidase. On the other hand, bacteriolysis of E.coli cell wall by zinc ions is attributed to the destruction of outer membrane structure due to degradative enzymes of lipoproteins at N- and C-terminals, and also is dependent on the activities of PGN hydrolases and autolysins of amidases and carboxypeptidase-transpeptidase. Zinc ions induced ROS such as O2 －, H2O2, ･OH, OH－producing in bacterial cell wall occur oxidative stress