Streptomycin Action and Anaerobiosis.

The question was asked whether the insensitivity to dihydrostreptomycin and streptomycin exhibited by facultatively anaerobic organisms growing strictly anaerobically could be due entirely to the lack of an anaerobic mechanism for the uptake of these antibiotics. A technique is described here which allows exposure of Escherichia coli B to dihydrostreptomycin, under conditions which are known to promote its intracellular accumulation, for a time, followed by further incubation in a growth medium under aerobic as well as under strictly anaerobic conditions, after removal of the extracellular antibiotic. With this technique it was possible to make a quantitative comparison of the inhibitory effects of dihydrostreptomgcin on aerobic and anaerobic growth of E. coli B under conditions where no further uptake of the antibiotic could occur. The results show that for any given treatment of E. coli B with dihydrostreptomycin, subsequent aerobic and anaerobic growth rates are inhibited to exactly the same extent. It is concluded that the need for aerobic metabolism in the expression of antibiotic effect by dihydrostreptomycin is concerned only with its uptake into the organisms.