Mycobacterium madagascariense sp. nov.

Abstract

Strains of a new type of rapidly growing, scotochromogenic mycobacterium were isolated from sphagnum vegetation in Madagascar. These strains grew at 31 and 22°C but not at 37°C, possessed catalase, acid phosphatase, and arylsulfatase activities, split urea and pyrazinamid, hydrolyzed Tween, and produced acid from glucose, L-arabinose, fructose, mannitol, rhamnose, sorbitol, xylose, and trehalose. Furthermore, they metabolized iron and possessed putrescine oxidase activity but did not reduce nitrate. The internal similarity level of the strains, as determined by taxonomic methods, was 92.50%. The phylogenetic relationships of strain P2T (T = type strain) with members of the genus Mycobacterium, as determined by comparing the 16S rRNA primary structure of this strain with the 16S rRNA primary structure of this stain with the 16S rRNA primary structures of 41 other mycobacterial species, indicated that strain P2T belongs to a separate line of descent within a cluster that includes Mycobacterium phlei, Mycobacterium smegmatis, Mycobacterium confluentis, Mycobacterium flavescens, and Mycobacterium thermoresistibile. Hence, the new strains are considered members of a new species of nonpathogenic, rapidly growing mycobacteria, for which we propose the name Mycobacterium madagascariense. Strain P2 is the type strain; a culture of this strain has been deposited in the American Type Culture Collection as strain ATCC 49865.