Sphingobacterium cellulitidis sp. nov., isolated from clinical and environmental sources

The taxonomic position of two isolates belonging to the genus Sphingobacterium was determined. The first isolate, R-53603T, was obtained from purulent discharge from the toe of a cellulitis patient in Kuwait. Comparative 16S rRNA gene sequence analysis revealed 99.87 % similarity of R-53603T with environmental isolate P031 (=R-53745) originating from activated sludge in Singapore. The two isolates were phylogenetically positioned on the same sub-branch. Highest 16S rRNA gene sequence similarity was found with the type strains of Sphingobacterium mizutaii (98.23 %), Sphingobacterium lactis (97.78 %) and Sphingobacterium daejeonense (97.14 %). DNA-DNA hybridizations revealed <70 % relatedness between the two isolates and the type strains of the close phylogenetic neighbours S. mizutaii(18.0-24.5 %), S. lactis(20.3-25.9 %) and S. daejeonense(13.2-20.0 %). The high relative contribution of iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c) in the cellular fatty acid profiles of R-53603T and R-53745, the presence of sphingophospholipids, MK-7 as the dominant menaquinone and phosphatidylethanolamine as the major polar lipid in strain R-53603T are typical chemotaxonomic characteristics for members of the genus Sphingobacterium. Phenotypic features most useful for differentiation of the two novel strains from the most closely related species S. mizutaii include growth on MacConkey agar, and utilization of stachyose, guanidine HCl and lithium chloride in Biolog GEN III tests. Strains R-53603T and R-53745 thus represent a novel species, for which the name Sphingobacterium cellulitidis sp. nov. is proposed. The type strain is R-53603T (=LMG 28764T=DSM 102028T).