Ornithinimicrobium murale sp. nov., isolated from an indoor wall colonized by moulds

Abstract

A Gram-positive, non-spore-forming actinobacterium (01-Gi-040T) isolated from an indoor wall was studied to examine its taxonomic position. The isolate formed a very rudimentary substrate-mycelium that fragmented into rod-shaped to coccoid cells. On the basis of the 16S rRNA gene sequence similarity studies, strain 01-Gi-040T was shown to belong to the genus Ornithinimicrobium closely related to Ornithinimicrobium kibberense K22-20T (97.1 %), Ornithinimicrobium humiphilum DSM 12362T (96.2 %) and Ornithinimicrobium pekingense LW6T (96.1 %). A close relationship was also found with Arsenicicoccus bolidensis CCUG 47306T (95.9 %) and Arsenicicoccus piscis Kis4-19T (95.7 %) and a moderate relationship to the type strains of the genus Serinicoccus (94.0–94.1 %). The predominant menaquinone of strain 01-Gi-040T was MK-8(H4). The peptidoglycan contained ornithine as the diagnostic diamino acid. The polar lipid profile consisted of the lipids phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, an unknown phospholipid, an unknown aminolipid and two unknown phosphoglycolipids. The major fatty acids iso-C15 : 0, iso-C16 : 0 and iso-C17 : 0 were consistent with the fatty acid patterns reported for members of the genus Ornithinimicrobium . The results of DNA–DNA hybridizations, physiological and biochemical tests allowed phenotypic differentiation of strain 01-Gi-040T from the three recognized species of the genus Ornithinimicrobium . Strain 01-Gi-040T represents a novel species of the genus Ornithinimicrobium , for which we propose the name Ornithinimicrobium murale sp. nov., with the type strain 01-Gi-040T ( = DSM 22056T = CCM 7610T).