sp. nov., a slowly growing, non-scotochromogenic species, isolated from sputum of an elderly man.

A slowly growing mycobacteria, identified as strain TY59, was isolated from sputum of an elderly man with pneumonia. Sequencing of the 16S rRNA gene indicated that this strain was similar to members of the complex and closely related species. Strain TY59 has highest 16S rRNA gene sequence similarities to the type strains of (99.80 % sequence similarity), (99.74 %), (99.54 %), subsp. (99.54 %) and subsp. (99.54 %). Analysis of the internal transcribed spacer (ITS) and DNA-directed RNA polymerase subunit beta () sequences gave similar results to the 16S rRNA gene analysis. The closest species to strain TY59 were and with 97.90-98.25 % identity in ITS and 96.4-96.6 % in . The strain's 65 kDa heat shock protein () gene was different from those of , and subsp. with 72.4-74.2 % identity. Average nucleotide identity results showed a 93.4 % match to as the maximum value. Phenotypically, the non-chromogenicity, rough colonies, growth at 42 °C, negative results for nitrate reduction, β-glucosidase and Tween 80 hydrolysis, and positive results for catalase activity set this strain apart from closely related species. We propose that sp. nov. is a novel species of slowly growing mycobacteria. The type strain is TY59 (RIMD 1371001=CIP 111917).