Mycobacterium oryzae sp nov., a scotochromogenic, rapidly growing species is able to infect human macrophage cell line

Gram-stain-positive, acid-fast-positive, rapidly growing, rod-shaped bacteria (designated as strains JC290(T), JC430 and JC431) were isolated from paddy cultivated soils on the Western Ghats of India. Phylogenetic analysis placed the three strains among the rapidly growing mycobacteria, being most closely related to Mycobacterium tokaiense 47503(T) (98.8% 16S rRNA gene sequence similarity), Mycobacterium murale MA112/96T (98.8 %) and a few other Mycobacterium species. The level of DNA-DNA reassociation of the three strains with M. tokaiense DSM 44635(T) was 23.4 +/- 4% (26.1 +/- 3 %, reciprocal analysis) and 21.4 +/- 2% (22.1 +/- 4 %, reciprocal analysis). The three novel strains shared >99.9% 16S rRNA gene sequence similarity and DNA-DNA reassociation values >85 %. Furthermore, phylogenetic analysis based on concatenated sequences (3071 bp) of four housekeeping genes (16S rRNA, hsp65, rpoB and sodA) revealed that strain JC290(T) is clearly distinct from all other Mycobacterium species. The three strains had diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositolmannosides, unidentified phospholipids, unidentified glycolipids and an unidentified lipid as polar lipids. The predominant isoprenoid quinone for all three strains was MK-9(H-2). Fatty acids were C-17 : 1 omega 7c, C-16 : 0, C-18 : 1 omega 9c, C-16 : 1 omega 7c/C-16 : 1 omega 6c and C-19 : 1 omega 7c/C-19 : 1 omega 6c for all the three strains. On the basis of phenotypic, chemotaxonomic and phylogenetic data, it was concluded that strains JC290(T), JC430 and JC431 are members of a novel species within the genus Mycobacterium and for which the name Mycobacterium oryzae sp. nov. is proposed. The type strain is JC290(T) (=KCTC 39560(T)=LMG 28809(T)).