[Pathogenicities of Mycobacterium intracellulare and M. avium strains to the mice which were isolated from non-tuberculous mycobactriosis patients].

The virulence of 5 strains of M. intracellulare and 6 strains of M. avium to mice were examined. The former bacteria were obtained from the patients with mycobacterial pulmonary disease and the latter were from AIDS patients respectively. C57BL/6 (NRAMP-1 susceptible) and its NRAMP-1 congenic mice (resistant) were used to evaluate the virulence of these bacteria. Three of the 5 strains of M. intracelllulare showed a relatively high virulence. They grew in the liver, spleen and lungs of susceptible mice and even in the lungs of resistant mice. On the other hand, none of 6 strains of M. avium could grow in either susceptible or resistant mice. In conclusion, our mouse model may be a useful tool for evaluating the virulence of bacteria isolated from mycobacteriosis patients.