From a 4 years old male patient with subcutaneous abscess in the preauricular region, a strain belonging to the scotochromogenic group of atypical mycobacteria was isolated which was thought to have pathogenic relation with the disease. This paper reports the results of various examinations on the biological, biochemical and animal experimental characteristics of this strain.
Since May, 1967, the patient noted a tumor formation in the preauricular region. From the pus obtained by the puncture of the tumor, the acid-fast bacilli were isolated, and thecolonies were yellowish orange in color and smooth and moist in nature. As the strain was proved to be sensitive to streptomycin, the patient had been treated by streptomycin combined with surgical treatment. Since February, 1968, the tumor has been cured, and the acid-fast bacilli have become negative.
The strain took 3 weeks to grow on 1% Ogawa's egg media. The optimal temperature for the growth was 37°C, and it was not photochromogenic. As to the other properties, a niacin test was negative, a neutral red test was negative if the extraction was done with 50% methanol, while it was strongly positive if the extraction was done with absolute methanol. Moreover, an urease test was negative, the resistance to decolorizing effect of boiling water (Kf) was 1.5minutes, a catalase activity was distinct and a cord formation property was not found.
For the purpose of investigating pathogenicity, mice were inoculated intravenou s ly through the tail vein with 1 mg of the strain, but no mice showed pathologic change on autopsy. A half of mice which were inoculated with 8 mg of the strain died in about a week after infection. The surviving mice were sacrificed on the 58th day. Among died mice, macroscopically, the lung was congested, the spleen was swollen and the liver showed spotty necrosis. Microscopically, non-specific pneumonia was recognized in the lung. Among sacrificed mice, no macroscopical change was noticed, however, in microscopic observation of the lung, scattered proliferative tuberculous lesions consisting mainly of epithelioid cells were observed. The demonstration of the acid-fast bacilli by staining revealed that a great number of organisms were found in the inflammatory lesions of the lung of the deceased mice, but in the sacrificed mice, no bacilli was found even in the tuberculous lesoins of the lungs.
In order to examine the degree of multiplication of the strain in the lung of mice, 11 mice were inoculated intravenously with 1 mg of the organisms, and were sacrificed at 2, 4, 6 and 8 weeks after the infection. The lung obtained from the sacrificed mice was subjected to the cultural examination for the enumeration of acid-fast bacilli contained. From 2 mice viab le organisms could be recovered.
From the above - m entioned facts it is concluded that the pathogenicity of the present strain against mice is not so distinct. Furthermore, the result of the pathogenicity experiment

View full abstract

The base compositions of desoxyribonucleic acid (DNA) isolated from 6 strains of Mycobacteria including human type, bovine type, avian type, nonphotochromogen and saprophyte, were studied.
DNAs were extracted from the mycobacterial cells disrupted by means of grinding with sea sands and dryice, in borate buffer containing 1.0m NaC1, and were precipitated by isopropyl alcohol after deproteinization with phenol. DNAs obtained were purified by treatments of trypsin, activated charcoal and ribonuclease. Purified DNAs were hydrolysed with formic acid, and GC contents were estimated by paperchromatography.
The results obtained demonstrated that GC contents of Mycobacteria tested were 65.5 to 68.2%, and that mycobacterial DNAs were GC type. These DNA ratios could not be used fo r the classification of Mycobacteria, because there were only a slight difference of the ratios among various types of Mycobacteria.

View full abstract