A new practical classification of the mycobacteria.

A new classification is presented for mycobacteria cultured from clinical specimens. Five categories were defined on temperature requirement, and these were subdivided into 14 groups by pigmentation, oxygen preference and Tween hydrolysis. Support for some of the groups and for the recognition of certain important species within others was provided by drug-sensitivity tests. Less than 1-0% of the opportunist mycobacteria met in Britain eluded classification by these means.