The Behaviour of Mixtures of Streptomycin-sensitive and -resistant Tubercle Bacilli in Liquid Medium Sensitivity Tests

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Abstract
Strains of Mycobacterium tuberculosis were isolated from the sputum of patients prior to and during treatment with streptomycin and tested for sensitivity on a modified Tween 80-albumin liquid medium and the same medium without Tween 80. The proportions of resistance to sensitive tubercle bacilli, after 7 days, varied from 1:6 to 1:130; after 10 days, they varied from 1:37 to 1:2700; after 14 days, from 1:440 to 1:180,000. The growth rate is greater in medium without Tween 80 than with it. Cultures maintained at room temp. in the dark for about a yr. did not change their degree of sensitivity.