Physiological Studies on the Metabolic Activities of Streptomycin-Resistant B. Dysentheriae. 1. The Carbohydrate Metabolism of Streptomycin-Resistant Sh. flexneri 2a

The resistance to streptomycin should be demonstrated by some differencies in metabolic reactions detectable by comparisons made between resistant and susceptible bacteria. This paper is concerned with the examination of the glucose metabolism of streptomycin-susceptible and streptomycin-resistant strains of Sh. flexneri 2a. The resistant strains was obtained by serial transfers in progressive levels of streptomycin. This resistant variant could withstand at least 10,000γ per ml of streptomycin. 1) The oxidative abilitys of the resistant strains is considerably less on pyruvate among the components of the citric acid cycle than is that of the susceptible strain. 2) Pyruvic acid, lactic acid, and acetic acid accumulates during the oxidation of glucose by resistant and susceptible strains. The amount of pyruvic acid produced from glucose by resistant strain is more than that by susceptible strain. In the rate of consumptions of glucose between resistant and susceptible strains there is much less difference. 3) No significant difference between both strains is detected in anaerobic metabolism of glucose. 4) Resistant strains which has grown on continued subculture by serial transfer in the medium not containing streptomycin possess still these properties. This culture was also found to be resistant to at least 10,000γ per ml of streptomycin. 5) It is suggested that streptomycin-resistant and susceptible strains dissimilates glucose mainly by way of Embden-Myerhof pathway, and also have Warbung-Dickens pathway as an alternate pathway. 6) Streptomycin-susceptible strain growes more rapidly than streptomycin-resistant strain in shaking culture. 7) These results suggests that streptomycin-resistant strain is more fermentative in the metabolism of glucose than streptomycin-susceptible strain, and a significant difference between streptomycin-resistant and streptomycin susceptible strains exists in pyruvate metabolism and its terminal respiration system.