抄録
In the course of primary cultivation, not only the supposed murine leprosy bacillus but also pigmented colonies of acid-fast bacilli were isolated from the tissues of mice in experimental murine leprosy. Of 612 specimens from the mice previously infected with the Hawaiian strain 11 yielded such colonies and 3 cultures were also obtained from among 306 specimens with the Keishicho strain.
Tables 1 & 2 give the outlines of primary isolation of these cultures : source of materials, decontamination treatment, culture results, and their correlation on primary culture with the supposed murine leprosy bacilli. In these experiments the animals with the Hawaiian strain were killed during the period of 1 to 11 months after inoculation and the mice with the Keishicho strain were killed from 3 to 13 months after. These pigmented colonies, however, were obtained only from the mice of long standing, that is, from those which were sacrificed 6.5 months or more after inoculation. In the case of the mice with the Hawaiian strain, as indicated in Table 3, the tissues from which such colonies were isolated were the spleen, the liver and the lungs ; most often from the latter. With the Keishicho strain, however, they were isolated only from superficial lymph nodes and local site of the injection.
All of the above isolates were found to belong to Runyon's Group IV organisms. Their colonies grown ogawa's egg and egg yolk media were uniformly S type and yellow-colored. Drug sensitivity test on 7 strains of them revealed that they were in general less susceptible to the anti-tuberculous drugs than the tubercle bacillus (Table 4). Virulence test on the same strains was made by inoculating mice intravenously with 0.1 mg amount of the bacilli. The animals were killed after a period of 1 to 6 months and evaluation was made according to gross involvement, spleen weight per gram of body weight, and the results of quantitative culture from the lungs and spleen. There was no gross evi-dence of disease, except that the spleen of a few animals at 1 month were found to be suggestive of being swollen. Table 5 shows that the bacilli of 4 strains disappeared from the tissues by 3 months after injection, while the ones of the other three survived there till 3 or 6 months later.
