Isolation and characterization of a unique group of slowly growing mycobacteria: Description of Mycobacterium lentiflavum sp. nov

Abstract

A distinct group of slowly growing mycobacteria was identified on the basis of growth characteristics, biochemical and lipid profiles, and nucleic acid analyses. The isolates showed growth at 22 to 37°C, yellow pigmentation, and negative tests for Tween 80 hydrolysis, nicotinic acid, nitrate reductase, and urease; tests for arylsulfatase, pyrazinamidase, and heat-stable catalase were variable. Analysis of cellular fatty acids by gas-liquid chromatography and mycolic acids by thin-layer chromatography and high-performance liquid chromatography indicated a distinctive pattern which was unlike those of other species. Determination of the 16S rRNA gene sequence showed a unique sequence closely related to Mycobacterium simiae and M. genavense. On the basis of DNA homology studies, we suggest that these organisms are representatives of a novel species, for which the name M. lentiflavum sp. nov. is proposed.