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Recently, as the incidence of tuberculosis caused by Mycobacterium tuberculosis decreased the importance of pulmonary disease attributable to the infection with nontuberculous mycobcateria becomes apparent. The main pathogens of nontuberculous mycobcaterial disease(mycobacterioses) are M.Kansaaii, M. avium-intracellulare-scrofulaceum complex and M. fortuitum-chelonei complex. These organisms produce human pulmonary infections, clinically or histologically indistinguishable from tuberculosis. Moreover, of great concern is the definitive resistance of these organisms to many of anti-tuberculosis drugs. Consequently, a simple test, applicable in clinical laboratories, is of great vaiue for the differetion of mycobacterioses from tuberculosis. Tuberculin has long been used widly as a standard diagnostic antigen, paricularly in the epidemiologic survey of tuberculosis. A single tuberculin test, however, has a disadvantage that in the patients with diseases due to nontuberculous mycobacteria the response to the standard tuberculin may be negative. Comparative skin tests using standard tuberculin(PPD-S) and the sensitins (skin test antigens) prepared from various nontuberculous mycobacteria revealed that in general the patients infected with various mycobacteria reacted most intensely to the PPD’s prwpared from the homologous organisms. However, from the practical point of view, a single comparative tuberculin test using PPD-S prepared from M. tuberculosis and a sensitin prepared from a certain representative of nontuberculous mycobacteria appeared to be much more ideal and desirable. In this study, an attemot was made to select a representative sensitin of nontuberculous mycobacteria that can be used for differentiation of the sensitization due to the infections with nontuberculous mycobacteria from the one due to tubercle bacilli. Sensitivities and specificities of the tuberculin and sensitins prepared from the one due to tubercle bacilli. Sensitivities and spericities of the tuberculin ans sensitins prepared from M. tuberculosis(PPD-S), M.Kansaaii(PPD-Y), M. avium (PPD-A) and M. intracellulare(PPD-B) were assessed in the guinea pigs sensitized with homologous and heterologous organism of mycobacteria. In addition, the diagnostic evaluation of a single comparative skin test with PPD-S and PPD-A in animals senitized with nontuberculous mycobacteria as well as M.tuberculosis and M. bovis was made. The animals sensitized with M. Kansaaii and M. avium-intracellulare-scrofulaceum complex reacted most intensley in the skin test to homologous PPD’s PPD-Y and PPD-A, respectively. Moreover, in the comparative studles with PPD-S and PPD-A in guinea pigs sensitized with nontuberculous mycobacteria, the animals sensitized with M. tuberculosis, M. bovis and M.Kansaaii gave more intense reactions to PPD-S, whereas the animals sensitized with M. avium-intracellulare-scrofulaceum complex responded dominantly to PPD-A , and animals sensitized woth other atypical mycobacteria gave a little more intense skin reactions to PPD-A than PPD-S. This result suggested that a single comparative skin test using PPD-S and PPD-A would be of value for the presumptive differentiation of sensitizations of the subjects elicitied by the infections with nontuberculous mycobacteria from that with tubercle bacilli.
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