Relationship between Mycobacterium nonchromogenicum, Mycobacterium terrae, Mycobacterium novum and Subgroup "V" (Mycobacterium triviale)

Abstract

Comparison was made among Mycobacterium nonchromogenicum, M. terrae, M. novum and subgroup "V" (M. triviale). These organisms together are differentiated from other mycobacteria of group II and group III by the following characters: (1) Sensitiveness to ethambutol; (2) Tolerance to nitrite; (3) Tolerance to Tween 80; (4) In-ability to utilize glucose and succinate in the presence of glutamate. To exclude the influence of growth rate, rough colony mutants (R-type mutants) were isolated from M. nonchromogenicum, M. terrae and M. novum and compared with each other and subgroup "V" that was originally of R-type. The R-type mutants of M. nonchromogenicum were similar to those of M. terrae, with the exception of the intensity of nicotinamidase and pyrazinamidase activities. These two have been suggested to belong to the same taxon, appropriate name of which is M. nonchromogenicum. The R-type mutants of M. novum were similar to the subgroup "V", with the exception of the intensity of arylsulfatase activity. It has been considered that subgroup "V" is an R-type mutant of M. novum. Although M. nonchromogenicum and M. novum could be differentiated from each other by the intensity of the arylsulfatase, nicotinamidase and pyrazinamidase activities and requirement of nitrogen compounds, these two organisms are differentiated from other mycobacteria by the same characteristics and are therefore considered to be closely related organisms.