Immunodiffusion and lipid analyses in the classification of "Mycobacterium album" and the "aurantiaca" taxon.

Comparative immunodiffusion studies were performed on representative strains of "Mycobacterium album", the "aurantiaca" taxon and an "aurantiaca"-like group of actinomycetes, using reference systems representing 25 taxa assigned to the genera Arthrobacter, Corynebacterium, Kurthia, Mycobacterium, Nocardia, Rhodococcus, Streptomyces and the "aurantiaca" taxon. Thin-layer chromatographic analyses of whole-organism methanolysates were carried out on single strains of "Mycobacterium album" and the "aurantiaca"-like taxon. Both the distribution of precipitinogens and the type of mycolic acids determined showed that the "Mycobacterium album" and "aurantiaca" strains were closely related to one another, but not to the "aurantiaca"-like strains. The aggregate "aurantiaca" taxon, containing "Mycobacterium album" and the "aurantiaca" taxon, can be distinguished from the established mycolic-acid containing taxa, Corynebacterium, Mycobacterium, Nocardia and Rhodococcus, using both serological and lipid data. Further studies on additional strains are needed to determine whether the aggregate "aurantiaca" taxon merits generic status.