Resistance to Rifampin and Lysozyme of Strains of Some Species of Mycobacterium and Nocardia as a Taxonomic Tool

Examination of 682 strains representing four species of mycobacteria (Mycobacterium phlei, M. smegmatis, M. fortuitum, and M. marinum) and seven species of nocardiae (Nocardia asteroides, N. caviae, N. brasiliensis, N. autotrophica, N. dassonvillei, N. madurae, and N. pelletieri) indicated that, with the exception of N. madurae and N. pelletieri, resistance to rifampin (20 μg/ml) is a useful property for describing these species. Resistance to lysozyme (300 to 500 U/ml) is taxonomically useful for delineating all 11 species.