THE GROWTH OF MYCOBACTERIUM TUBERCULOSIS AS A FUNCTION OF ITS NUTRIENTS

Abstract

A method is descr. that permitted the quantitative measurement of the diffuse growth of M. tuberculosis in sorbitan monooleate medium. This method was applied to the study of the growth of M. tuberculosis as a function of its C and N sources. In the presence of an ammonium salt and glucose, the growth rate depended on the initial concn. of glucose in the medium and reached its upper limit at a concn. of 10 mg./ml. When glucose was present in the medium in small amts., it became the limiting factor for growth. The max. bacterial yield in dry wt. was 25% of the wt. of the glucose supplied. When ammonium N was present in limiting amts. and glucose was in excess, the total amt. of bacterial growth was proportional to the initial concn. of the ammonium salt. When maximal growth was reached under these conditions, autolysis of the bacteria followed at a more or less rapid rate depending on the initial glucose concn. in the medium. Expts. designed to analyze this phenomenon suggested that the bacteria, which were growing in the presence of limiting amts. of the N source and an excess of the C source, continued proliferation not only until the N source in the medium was depleted but also for at least one generation beyond the point of N exhaustion.