Following Corper's (1918) report on the virulence of tubercle bacilli isolated from the sputa, Griffith(1924) isolated "atypical tubercle bacilli" from the patients with pulmonary tuberculosis and indicated the significance of such an atypical acid-fast organism as a possible cause of pulmonary diseased state in human beings. Pollak (1951) and Buhler (1953) made reports of 4 cases in which cause of the death could be attributed to the infection with atypical acid-fast bacilli.
Willis et al. (1952) isolated acid-fast organisms that were similar to tubercle bacilli in staining property and method of culture but without any pathogenicity to warm-blooded animals. Bergey (1957) established the bacteriological system of acid-fast organisms. Runyon (1959) isolated acid-fast organisms from the patients whose clinical and X-ray findings were very much similar to those of pulmonary tuberculosis and this observation resulted in the recognition of human pathogenicity of such acid-fast organisms.
The results of intensive works firmly established that ;many of acid-fast organisms resembling human type of tubercle bacilli were widely distributed in natrue. Similarly, isolation of acid-fast organisms differed from human type of tubercle bacilli have been made from variable sources of human specimens such as sputum, pu, lupus tissue, and pleural fluid (Beaven, 1931; Cummins, 1933; Branch, 1933; Pinner, 1935; Cruz, 1938; Feldman, 1943; Mac Callum, 1948; Linell, 1954).
Among these acid-fast organisms some of them have become classified as M. fortuitum, M. ulcerans, M. malinum and etc. according to their unique characteristics in bacteriological findings and clinical features which were attributed to the infection with such organisms. However, many of therm still remains under the category of "atypical tubercle bacilli, atypical acid-fast microorganisms, unusual acid-fast bacilli and etc."
In recent years an increasing emphasis has been placed on atypical mycobacteria and atypical mycobacteriosis. Reports on the cases in which acid-fast organisms, resembling human type of tubercle bacilli but having unique characteristics, apperared to be responsible for the diseased conditions, were made by Engbaek(1957), Nassau (1957) and Oosterbaan(1959).
In 1959, a symposium on "So-called atypical mycobacteria" was held at the 15th International Association of Tuberculosis Prevention in Istanbul, Turkey, and Accumulating evidences provided by case reports and epidemiological studies established that atypical mycobacteria could become the cause of 'pulmonary
diseases' in human beings. These resulted in the activation of works on classification of such atypical mycobacteria. However, it was pointed out by Kubica(1966) that a complete and through classification of atypical mycobacteria might not be easily accomplished in taking into consideration of experimental
method, technical conditions and probable emergence of variants of the organisms.
Though significant decreases in morbidity rates of tuberculosis and leprosy have been noted in recent years in Korea, intensive works appears to be necessary in the field of atypical mycobacteria and the diseases due to such organisms. Contrary to
such a great demand in the works on atypical mycobacteria and atypical mycobacteriosis, studies made in this field are significantly limited at the moment.
In order to provide fundamental informations in the assessment on atypical mycobacteriosis, its clinical symptomatology and its epidemiological features in Korea, studies were made on bacteriological characterization of atypical mycobacteria isolated and identified from a total number of 1,636 sputa collected from the cases of pulmonary tuberculosis and pulmonary diseases and healthy controls, and on the analysis of symptomatology and clinical findings of bacteriologically-proven cases of atypical mycobacteriosis.
With a total number of 1,636 sputa collected from the cases of pulmonary tuberculosis and healthy controls, bacteriological study of atypical mycobacteria and an analysis of bacteriologically-proven cases of atypical mycobacteriosis were
made to define the status of atypical mycobacteriosis in this sample population, and the results are summarized as follows;
1. A total of 627 strains of mycobacteria was isolated from 1,636 sputum specimens, i.e., 622 strains (61.6%) from 1,017 specimens of pulmonary tuberculosis patients and 5 strains(0.8%) from 619 specimens of healthy women.
2. The isolated strains of mycobacteria consisted of 63 strains (10.0%) of atypical mycobacteria and 564 strains (90.0%) of human type of tubercle bacilli. All of these atypical mycobacteria were isolated from the sputa of the cases who had been clinically diagnosed as pulmonary tuberculosis and treated with anti-tuberculosis chemotherapeutics.
3. By classification of Runyon group, the strains of isolated atypical mycobacteria consisted of 25 strains(42.5%) of scotochromogen, 32 strains(49.0%) of non-photochromogen, 6 strains (8.5%) of rapid grower, and none of photochromogen.
4. According to the patterns of biochemical tests, 25 strains of scotochromogen could be further subdivided into 4 groups, 32 strains of non-photochromogen into 5 and 6 strains of rapid grower into 2.
5. In drug sensitivity test, it was observed that all of isolated atypical mycobacteria were resistant to INH, 31 strains (50%) to SM (10r/ml), and 30 strains (48%) to PAS (10r/ml).
6. Among 27 of pulmonary tuberculosis cases who remained through 2 years of follow-up study, 10 cases yielded identical atypical mycobacteria in 3 times of consecutive bacteriological examination of the sputa. In analysis of clinical and X-ray findings of those 10 cases it was found that clinical symptoms in these patients suffering from chronic pulmonary disease caused by infection with atypical mycobacteria appeared not to be milder than those in pulmonary tuberculosis patients, and that such cases of atypical mycobacteriosis had been misdiagnosed as pulmonary tuberculosis and had not received proper treatments for their diseased condition.
These data strongly indicate that in Korea more intensive studies on atypical mycobacteria have to be made in the bacteriological investigation of pulmonary diseases caused by mycobacterial infections.