Comparative trials with different decontaminating agents for growing Mycobacterium tuberculosis from sputum specimens.

A reliable culture technique for mycobacteria to enable precise taxonomic and biological identification to be made, e.g., virulence and sensitivity or resistance to the major and minor antituberculosis drugs, is one of the basic requirements of efficient and economic tuberculosis control measures. Several of the methods employed for this purpose have been studied systematically. Many of these methods make use of various detergents, especially quaternary ammonium bases in different combinations, which possess strong bacteriostatic or bacteriocidal properties and decontaminate sputum samples without, however, affecting the viability of mycobacteria.A series of experiments to study the effect of sodium lauryl sulfate and of pancreatin, both in combination with sodium hydroxide, and of a new detergent, di-isobutal-naphthalin-sulfonate (Nekal Bx) on the growth of mycobacteria in liquid and solid media were carried out. As a control technique, the processing of samples of pathological material with hydrochloric acid and sodium hydroxide was studied.On the basis of these experiments, the sodium lauryl sulfate method proved to be promising, both for the rapid growth and characterization of the colonies, and for producing the lowest contamination rate in cultures. However, none of the 4 techniques was sensitive enough under the experimental conditions to demonstrate mycobacteria in sputum samples containing few organisms.