Mycobactins and exochelins of Mycobacterium tuberculosis, M. bovis, M. africanum and other related species

Following iron-deficient growth, mycobactins and exochelins were isolated from 11 strains of Mycobacterium tuberculosis (including type strains of the virulent H37Rv and avirulent H37Ra organisms) as well as from M. bovis (one strain), M. bovis BCG (two strains), M. africanum (eight strains) and M. xenopi (one strain) but not from M. microti (one strain). The mycobactins from the tuberculosis group (M. tuberculosis, M. bovis and M. africanum) were identical and could each be resolved into four compounds by thin-layer chromatography (TLC) and into several fractions by high-performance liquid chromatography, supporting previous claims that this group is a single taxon. Exochelins were all chloroform-soluble and showed no species specificity; no single exochelin was recognized by TLC that had not been previously seen in M. avium or a related species.