Abstract
A fast-growing, non-chromogenic, acid-fast-staining bacterium (DL90(T)) was isolated from a peat bog in northern Minnesota. On the basis of 16S rRNA gene sequence similarity (99.8 % identity with Mycolicibacterium septicum and 98 % with Mycolicibacterium peregrinum) and chemotaxonomic data (fatty acid content), strain DL90(T) represents a member of the genus Mycolicibacterium. Physiological tests (growth curves, biofilm formation, antibiotic sensitivity, colony morphologies and heat tolerance) and biochemical analysis (arylsulfatase activity and fatty acid profiles) distinguish DL90(T) from its closest relative M. septicum. Phylogenomic reconstruction of the 'Fortuitium-Vaccae' clade, digital DNA-DNA hybridization (DDH) values of 61 %, and average nucleotide identity (ANI) values of approximately 95 % indicate that DL90(T) is likely to be diverged from M. septicum. Thus, we propose that DL90(T) represents a novel species, given the name Mycolicibacterium nivoides with the type strain being isolate DL90(T) (=JCM 32796(T)=NCCB 100660(T)).