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

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.