The Effect of Germicides on the Viability and on the Respiratory Enzyme Activity of Gonococcus.

The relationship between enzyme activity and destruction of bacteria by disinfectants has been the subject of numerous investigations in recent years. In 1927, Quastel and Wooldridge studied the effect of chemical and physical agents on various dehydrogenases of Escherichia coli. In several experiments, the treated organisms were subcultured to compare the viability of the organisms with their enzyme activity. When the dehydrogenases were completely inhibited (particularly those dehydrogenating the sugars), the organisms were found to be dead or greatly reduced in number. Casman and Rettger (1933), working with the effect of different temperatures on several species of the genus Bacillus, as well as some strict thernophiles, pointed out that the succinic dehydrogenase system of most of the organisms appeared to be distinctly inhibited at the maximum temperature of growth. Paraphenylenediamine oxidase and catalase activities varied considerably in this respect. Qualitative methods were employed to detect the enzyme activities. Similar studies were also made by Edwards and Rettger (1937) as well as by Wedberg and Rettger (1941) with a wider variety of organisms; essentially the same methods as those of Casman and Rettger were used. Yudkin (1937) demonstrated that silver sulphate was lethal to suspensions of E. coli in concentrations much lower than those inhibiting the dehydrogenases (glucose, succinic, lactic and formic), hydrogenase and formic hydrogenlyase. Sykes (1939) studied the effect of alcohols and phenol derivatives on succinic dehydrogenase of E. coli. It was found that at concentrations of the germicides equal to those killing the organisms, the activity of the enzyme was considerably or completely inhibited. Rahn and Barnes (1933) reported on the different criteria of death of yeast cells. When the organisms were subjected to the action of heat or mercuric chloride, the rate of loss of reproduction was about twice as rapid as the loss of fermentation, about three times that of the loss of semipermeability, and about forty times as large as the rate of coagulation of the protoplasm. Rahn and Schroeder (1941) investigated the problem of enzyme inactivation as the cause of death of bacteria. Contrary to the work of Edwards and Rettger (1937), these workers found that when half of the catalase and succinic dehydrogenase activities of Bacillus cereus were inhibited at 46° and 50°C., more than 99.9 per