%0 Journal Article %A Brown, Annie M. %A Young, P. A. %T A Dilution Method for the Assay of Streptomycin %D 1947 %J Microbiology, %V 1 %N 3 %P 353-360 %@ 1465-2080 %R https://doi.org/10.1099/00221287-1-3-353 %I Microbiology Society, %X SUMMARY: A dilution method for the assay of streptomycin is described using a digest nutrient broth as the test medium and a certain strain of Escherichia coli (Bacterium coli) as the test organism. The inhibition end-point is estimated turbidi-metrically by comparison with that in a standard solution of streptomycin base. The accuracy of the method when employed as described is of the order of ± 15%. It is necessary to control the dilution of the test medium, the temperature of incubation of the tests, the size of the inoculum and hydrogen-ion concentration in order to obtain consistent results. With dilution of the medium the sensitivity of the test is increased while its accuracy is decreased. The use of an inoculum of constant size is important, and an incubation temperature of 28° is found to be more satisfactory than 37°. Medium with a hydrogen-ion concentration of pH 7·6 affords greater sensitivity than that with a lower pH value. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-1-3-353