Thin-layer chromatography of lipid antigens as a means of identifying nontuberculous mycobacteria.

The previously described thin-layer chromatography procedure (Brennan et al., J. Clin. Microbiol. 8:374-379, 1978) for identifying serovars of the Mycobacterium avium-M. intracellulare-M. scrofulaceum complex, based on their specific C-mycoside glycopeptidolipid antigens, has now been extended to all 31 known serovars. Photographs of the characteristic pattern of the glycopeptidolipids are presented. Although the procedure is fraught with the difficulties inherent to comparative thin-layer chromatography, it is particularly suitable for the screening of isolates which are not amenable to seroagglutination, such as those which autoagglutinate or for which antisera are not presently available. In this way it was possible to tell whether isolates were of the M. avium-M. intracellulare-M. scrofulaceum complex and whether or not they had previously been recognized. Knowledge of the chemical features of the typing antigens nontuberculous mycobacteria other than M. avium-M. intracellulare-M. scrofulaceum strains also enables us to develop thin-layer chromatography systems for the identification of M. kansasii, M. szulgai, members of the M. gordonae complex, M. terrae, M. xenopi, and M. gastri.

Peptidoglycolipid nature of the superficial cell wall sheath of smooth-colony-forming mycobacteria.

The most superficial cell wall layer present in smooth-colony-forming mycobacteria was isolated from serovar 20 of the Mycobacterium avium-Mycobacterium intracellulare-Mycobacterium scrofulaceum (MAIS) serocomplex and examined chemically and by electron microscopy. Most (70 to 80%) of the fibrillar material consisted of an array of serologically active, acetylated C-myosidic peptidoglycoplipids with the basic structure (formula, see text) but in which the location of acetyl groups and the arrangement of monosaccharides have not been defined. Apparently, all serovars within the MAIS complex are characterized by structurally related superficies in which the monoglycosyl-lipopeptide portion is invariable but the oligosaccharide attachment is peculiar to each serovar. These unique inert structures may be an important factor in shielding the pathogen within phagolysosomes from lysosomal enzymes.