DEPENDENCE OF SOME STRAINS OF MYCOBACTERIUM-AVIUM ON MYCOBACTIN FOR INITIAL AND SUBSEQUENT GROWTH

This paper demonstrates that various degrees of mycobactin dependence exist within the M. avium group of mycobacteria and that this characteristic is not confined to M. paratuberculosis. The strains employed came from a wide range of animal species and all were virulent for chickens. Mycobactin dependence was observed in the M. avium serotypes 1, 2 and 3. The importance of employing a medium containing mycobactin for primary isolations from tissue containing only small numbers of viable units of M. avium is emphasized. This observation may be of interest in relation to the primary isolation of other species of mycobacteria.