Abstract
In the previous report (Tsukamura et al.: Kekkaku, 41: 401, 1966), the present writers stated that pathogenic scotochromogens isolated in Japan showed fairly uniform characters and were to be recognized as a species. These pathogenic scotochromogens were shown to be identical as Mycobacterium scrofulaceum (Tsukamura et al.: Kekkaku, 42: 219, 1967). On the other hand, slowly growing scotochromogens occurring in the soil showed similar characters with the pathogenic scotochromogens and were considered to belong to the same species (Tsukamura et al. : Kekkaku, 42: 15, 1967). These results suggest a hypothesis that the scotochromogens occurring in the soil or water (M. scrofulaceum) enter the human body and, if there exist some strains with high virulence among them, they cause an infection in the human, being influenced by the condition of the host. If this hypothesis is correct, it would be expected that sporadic isolates of the scotochromogens occurring in sputa are M. scrofulaceum and their virulence is weaker than that of the pathogenic scotochromogens (multiple isolates). The present paper dealt with the characters and virulence of the sporadic isolatescotochromogens.
