Nocardia grenadensis sp. nov., isolated from sand of the Caribbean Sea

Abstract

A Gram-stain-positive, non-spore-forming bacterium (GW5-5797(T)) was isolated on soil extract agar from sand collected at a depth of 5 m in the Caribbean Sea near Grenada. 16S rRNA gene sequence analysis and similarity studies showed that strain GW5-5797(T) belongs to the genus Nocardia, and is most closely related to Nocardia speluncae N2-11(T) (99.2% similarity) and Nocardia jinanensis 04-5195(T) (99.2%) and more distantly related to Nocardia rhamnosiphila 202GMO(T) (98.6%) and other Nocardia species. Strain GW5-5797(T) could be distinguished from all other recognized Nocardia species by sequence similarity values less than 98.5%. The peptidoglycan diamino acid was meso-diaminopimelic acid. Strain GW5-5797(T) exhibited a quinone system with the predominant compounds MK-8(H(4)ω-cyclo) and MK-8(H(2)). The polar lipid profile of GW5-5797(T) consisted of the major compounds diphosphatidylglycerol, phosphatidylethanolamine and an unidentified glycolipid, moderate amounts of phosphatidylinositol and a phosphatidylinositol mannoside and minor amounts of several lipids including a second phosphatidylinositol mannoside. The polyamine pattern contained the major compound spermine and moderate amounts of spermidine. The major fatty acids were C(16:0,) C(18:1)ω9c and 10-methyl C(18:0). These chemotaxonomic traits are in excellent agreement with those of other Nocardia species. The results of DNA-DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain GW5-5797(T) from the most closely related species, showing 16S rRNA gene sequence similarities >98.5%. Strain GW5-5797(T) therefore merits separate species status, and we propose the name Nocardia grenadensis sp. nov., with the type strain GW5-5797(T) (=CCUG 60970(T) =CIP 110294(T)).