Deoxyribonucleic acid relationships between different serovars of Mycobacterium avium, Mycobacterium intracellulare and Mycobacterium scrofulaceum.

M. avium and M. intracellulare are difficult to distinguish by means of biochemical tests and by means of numerical taxonomy. DNA-DNA hybridization confirms that these species are different but indicates that some serovars of M. intracellulare actually belong to the species M.avium, viz.: serovars 4, 5, 6 and 8. This corresponds to results obtained with sensitin tests on guinea-pigs. The status of strains belonging to serovar 9 is uncertain. The two strains investigated in this study were closely related to, but not identical with M. scrofulaceum serovar 41.