Abstract
A culture of an actinomycete isolated from greenhouse soil produced an antibiotic which inhibited only species of Mycobacterium, particularly the sapro-phytic species of Mycobacterium, and especially M. smegmatis. The characteristics of the culture are given, conditions for producing the antibiotic as well as some of the properties of the crude antibiotic (designated anti-smegmatis factor). The antibacterial spectrum was detd. using > 60 spp. of micro-organisms. In addition to M. smegmatis, M. phlei and M. tuberculosis variety hominis, no. 607, were inhibited by the antibiotic.