Changes of the biotype of Mycobacterium avium-Mycobacterium intracellulare complex causing lung disease in Japan

A survey was carried out on the biological and biochemical characteristics of 661 strains of Mycobacterium avium-M. intracellulare complex that caused lung disease in the period 1976 to 1986. The results showed that the proportion of strains which showed 2-week-arylsulphatase activity and that of those which were able to utilize glucose as sole carbon source in the presence of glutamate-nitrogen decreased markedly, and that the proportion of those which utilized neither n-butanol nor iso-butanol as sole carbon sources in the presence of ammoniacal nitrogen increased markedly over these 11 years. These findings indicate that the predominant biotype changed from M. intracellulare to M. avium during the period under study. This postulate is supported by a limited study of the serovars present among the isolates.