In a previous communications1) some characteristics of the acid-fast organisms which had been isolated from mice infected intravenously and subcutaneously with the Hawaiian strain of
M.lepraemuriumwere reported. The present paper describes some further differential characteristics of the organisms and an experimental study of the role of ingredients of the egg yolk medium.
Characteristics of the acid fast organisms grown in vitro: a) Growth response to the media for cultivation of mycobacteria.1)-Various media such as nutrient agar, glycerol agar, Kirchner's serum agar, 2) modified Kirchner's No. 3 agar, 3) blood No. 1 and No. 2 agars, 4) Dubos Tween-albumin liquid medium, and 1% Ogawa egg medium were testedfor their abilities to support the macroscopic growth of the organisms which had been subcultured on the egg yolk medium. All of them but the standard medium proved incompetent for supporting the growth of 39 cultures employed (Table 1). b) The length of the bacilli. The bacillary smears prepared from the growth of cultures and stained by Ziehl-Neelsen method were subjected to a measurement of length by light microscopy (450×mag.) with a scale in the ocular. The average for the maximum and the minimum length of the bacilli in 21 cultures examined were to be 10.9ν and 2.4ν, respectively. Thus, the bacilli grown in vitro were found to be about twice as long as the bacilli in the tissues of mice infected intravenously with a primary culture of the organisms 6 months before (Fig. 1 and Table 2).
c) Catalase.-The test on 5 cultures revealed that the organisms were weakly positive for catalase to the same extent as
M.tuberculosis (Table 3). And, so-called atypical mycobacteria showed higher activities than those organisms above.
The 1% egg yolk medium: This medium was used as the standard to examine the effect of removal of its ingredient(s) on in vitro growth of the organisms. Several modified egg yolk slants (Table 4) were tested for such purpose using 80 cultures of the organisms. Results in Table 5 showed that out of 13 cultures inoculated 10 cultures or 77 percent were positive by the use of the standard medium whereas only 3, i.e., 23 percent were positive by the one deprived of phosphate, 7 cultures or 54 percent positive without glutamate, but none without glycerol. An egg yolk saline medium (2: 1) containing no glycerol was also found to be useless. It was concluded that the only medium superior to the 1% egg yolk medium was the one deprived of malachite-green and all the other modified media gave results either negative or inferior to those of the standard one.
The results obtained above also suggest that the acid-fast organisms which have been isolated from infected mice with the Hawaiian strain and subcultures continuously on the 1% egg yolk medium do not belong to
M.tuberculosis, atypical mycobacteria,
M.paratu-berculosis, nor to
M.microti. It may be uggestive of murine leprosy bacillus.
抄録全体を表示