Sphingomonas hominis sp. nov., isolated from hair of a 21-year-old girl.

Abstract

A Gram-stain-negative, aerobic, motile strain, HHU CXWT, was isolated from hair of a healthy 21-year-old female student of Hohai University, Nanjing, China. The 16S rRNA gene sequence analysis indicated that HHU CXWT represents a member of the genus Sphingomonas with the highest sequence similarity (97.6%) to the type strain S. aquatilis JSS7T. HHU CXWT grew at 4-35°C and pH 6-8, with optimum growth at 28°C and pH 7. Tolerance to NaCl was up to 2% (w/v) with optimum growth in 0.5-1.0% NaCl. The major fatty acids were C16:0, C17:1ω6c, C18:1ω7c11-methyl, summed feature 3 (C16:1ω7c and/or C16:1ω6c), and summed feature 8 (C18:1ω7c and/or C18:1ω6c). The predominant isoprenoid quinone was ubiquinone-10. The polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), sphingoglycolipid (SGL), phosphatidylinositol mannosides (PIM), and an unidentified glycolipid (GL). The DNA G + C content was 67.1%. The average nucleotide identity (ANI)values and digital DNA-DNA hybridization (dDDH) between HHU CXWT and closely related members of the genus Sphingomonas were all below the cut-off level (95-96% and 70%, respectively) for species delineation. On the basis of the phenotypic, phylogenetic and chemotaxonomic characterizations, HHU CXWT represents a novel species of the genus Sphingomonas, for which the name Sphingomonas hominis sp. nov. is proposed. The type strain is HHU CXWT (= KCTC 72946T = CGMCC 1.17504T = MCCC 1K04223T).