Microbic Dissociation: II. The Tubercle Bacillus.

Abstract

In a previous communication 1 we called attention to the observation made on microbic dissociation of the tubercle bacillus. Two types of acid-fast organisms, a bovine and an avian type, were described, both of which dissociated into two colonies varying in structural characteristics, i. e., one was rough and irregular, while the other was perfectly smooth and appeared very much like moth balls. The bovine tubercle bacillus (B 1) is a culture of moderate virulence which has been in our possession for many years, and the avian culture was obtained from outside sources.

Further investigations have been made by subculturing the single colonies, with the hope of stabilizing their cultural characteristics. At present we feel that various colonies obtained by subculturing are more stable than those ordinarily obtained with other organisms. In all probability this is due to the fact that the tubercle bacillus develops very slowly, taking weeks for visible colonies to appear. In other words, dissociation may be in proportion to the rate of the multiplication of the organisms.

In this communication we shall describe two distinct acid-fast organisms isolated from the sputum of a patient suffering from pulmonary tuberculosis. These organisms were isolated by the author's method, i. e., equal parts of sputum and 4 per cent sodium hydroxide were mixed, shaken well and incubated for 15 minutes at 37.5° C., then centrifuged and the sediment neutralized with normal hydrochloric acid and inoculated on the surface of Petri plates of gentianviolet-egg medium, which lately has been modified, using the dye in dilution of 1:20,000 instead of 1:10,000.