Studies on the Mode of Action of the Phenolic Antibacterial Agent Fentichlor against Staphylococcus aureus and Escherichia coli II. The Effects of Fentichlor on the Bacterial Membrane and the Cytoplasmic Constituents of the Cell

Fentichlor produces rapid and marked damage to cell membranes of Staphylococcus aureus and Escherichia coli causing leakage of 260 nm material and pentose from whole cells, and lysis of spheroplasts of E. coli. Investigations indicate that Fentichlor‐induced membrane damage is related to bactericidal activity. Bacteriostatic concentrations of 10 μg/ml or less do not stimulate leakage while at higher concentrations there is a marked relationship between loss of viability and of metabolic pool material released. Drug concentrations producing 99·99% kill within 1 h correspond closely to minimum concentrations required to produce total loss of 260 nm material from the pool. Membrane damage caused by bactericidal concentrations of drug is irreversible and under conditions optimal for enzyme activity additional leakage of 260 nm material resulting from autolytic breakdown of insoluble nucleic acids also occurs. There is no evidence that Fentichlor produces precipitation of cell cytoplasmic constituents.