Streptomyces pluripotens sp. nov., a bacteriocin-producing streptomycete that inhibits meticillin-resistant Staphylococcus aureus

Abstract

Two novel actinobacteria, strains MUSC 135T and MUSC 137, were isolated from mangrove soil at Tanjung Lumpur, Malaysia. The 16S rRNA gene sequence similarity and DNA–DNA relatedness between strains MUSC 135T and MUSC 137 were 100 % and 83±3.2 %, confirming that these two strains should be classified in the same species. Strain MUSC 135T exhibited a broad-spectrum bacteriocin against the pathogens meticillin-resistant Staphylococcus aureus (MRSA) strain ATCC BAA-44, Salmonella typhi ATCC 19430T and Aeromonas hydrophila ATCC 7966T. A polyphasic approach was used to study the taxonomy of MUSC 135T, and it showed a range of phylogenetic and chemotaxonomic properties consistent with those of the genus Streptomyces . The diamino acid of the cell-wall peptidoglycan was ll-diaminopimelic acid. The predominant menaquinones were MK-9(H6), MK-9(H4) and MK-9(H8). Polar lipids detected were a lipid, an aminolipid, a phospholipid, phosphatidylinositol, phosphatidylethanolamine and two glycolipids. The predominant cellular fatty acids (>10.0 %) were anteiso-C15 : 0 (20.8 %), iso-C16 : 0 (18.0 %), iso-C15 : 0 (12.2 %) and anteiso-C17 : 0 (11.6 %). The whole-cell sugars were ribose, glucose and mannose. These results suggested that MUSC 135T should be placed within the genus Streptomyces . Phylogenetic analysis based on the 16S rRNA gene sequence exhibited that the most closely related strains were Streptomyces cinereospinus NBRC 15397T (99.18 % similarity), Streptomyces mexicanus NBRC 100915T (99.17 %) and Streptomyces coeruleofuscus NBRC 12757T (98.97 %). DNA–DNA relatedness between MUSC 135T and closely related type strains ranged from 26.3±2.1 to 49.6±2.5 %. BOX-PCR fingerprint comparisons showed that MUSC 135T exhibited a unique DNA profile. The DNA G+C content determined was 70.7±0.3 mol%. Based on our polyphasic study of MUSC 135T, the strain merits assignment to a novel species, for which the name Streptomyces pluripotens sp. nov. is proposed. The type strain is MUSC 135T ( = MCCC 1K00252T = DSM 42140T).