We were greatly impressed by the Joint Tuberculosis Committee guidelines on the management of opportunist mycobacterial infections.¹ We do, however, wonder why the word "opportunist" has been used to describe the mycobacteria, other than the M tuberculosis complex, that cause human disease. All mycobacteria causing disease, even the M tuberculosis complex, are opportunists. Thus, the latter are often spoken of as causing opportunist disease in HIV positive persons. Since the causative role of these other mycobacteria in human disease was established in the middle of the 20th century, a wide range of collective nouns has been applied to thematypical, anonymous, MOTT (mycobacteria other than tuberculosis), non-tuberculous, and tuberculoidas well as opportunist.

The distinguishing feature of almost all mycobacteria other than members of the M tuberculosis complex is that they live freely in the environment. For this reason the expression "environmental mycobacteria" has been in widespread use in recent . . . [Full text of this article]