Mycobacterium yongonense sp. nov., a slow-growing non-chromogenic species closely related to Mycobacterium intracellulare.

A slow-growing non-chromogenic mycobacterium was isolated from a patient with pulmonary disease. Phenotypically, strain 05-1390(T) was similar to Mycobacterium intracellulare ATCC 13950(T). The 16S rRNA gene sequence (1385 bp) of strain 05-1390(T) showed a high degree of similarity to those of the M. intracellulare complex, namely Mycobacterium marseillense 5351974(T) (100 %), M. intracellulare ATCC 13950(T) (99.8 %) and Mycobacterium chimaera DSM 44623(T) (99.9 %). Phylogenetic analysis based on internal transcribed spacer 1 (ITS1) and the hsp65 gene indicated that strain 05-1390(T) was closely related to M. intracellulare ATCC 13950(T), but that it was a distinct phylogenetic entity. Of particular interest, an analysis based on the rpoB gene (701 bp) showed that it is closely related to Mycobacterium parascrofulaceum ATCC BAA-614(T) (99.4 %), a scotochromogenic strain, rather than to the M. intracellulare-related strains. Unique MALDI-TOF MS profiles also supported the taxonomic status of this strain as a distinct species. These data support the conclusion that strain 05-1390(T) represents a novel mycobacterial species, for which the name Mycobacterium yongonense sp. nov. is proposed; the type strain is 05-1390(T) ( = DSM 45126(T) = KCTC 19555(T)).