REVERSAL OF THE STREPTOMYCIN INJURY OF ESCHERICHIA COLI

Abstract
The number of viable Escherichia coli in a young, actively growing culture is decreased approximately 99.9 per cent by a 30 second exposure to 25 ϕg. streptomycin/ml. The injury induced by the antibiotic is only potentially lethal, however, and may be reversed by subculture within 5 minutes into fresh culture medium, NH4NO3, NH4Cl, (NH4)2HPO4, NH4 citrate, and NH4 tartrate. Subculturing into water, glucose, or MgSO4 results in a more marked decrease in the number of viable organisms. In KNO3, NaNO3, K2HPO4, and Na2SO4 solutions reversal occurs first, followed by a rapid decrease in viability.