1998 年 3 巻 1 号 p. 23-29
The effects of polyoxyethylene cetyl ether (PCE) on the cellular uptake and the antibacterial activity of butyl p-hydroxybenzoate (BP) by bacteria were studied using an aqueous suspension of Escherichia coli. The BP in the cell suspension was distributed in the cells and aqueous phase. PCE added to the BP solution was responsible for reducing the BP uptake into the cells and inhibiting the antibacterial activity of BP due to the formation of a complex between BP and PCE micelles. The uptake and antibacterial activity of BP were proportional to the unbound BP concentration in the aqueous bulk solution. However, the addition of PCE repressed BP uptake in the cells and enhanced BP activity compared with those values expected from unbound BP in the aqueous surfactant solution. These results suggested that direct interactions between PCE and bacterial cells increased the susceptibility of bacteria. The decrease in BP uptake into bacterial cells was thus concluded to be responsible for the reduction in the antibacterial activity of BP in an aqueous surfactant solution, and the measurement of paraben uptake by microbial cells was found to be a reliable means for assessing inactivation in an aqueous solution in the presence of surfactants.
