Pigmentibacter ruber gen. nov., sp. nov., a novel bacterium of the family Silvanigrellaceae isolated from human blood

A Gram-negative, aerobic, non-motile, pleomorphic, red-pigmented bacterium, designated HNSRY-1T, was isolated from the blood sample of a near drowning patient in Republic of China. Strain HNSRY-1T grew at 15-37 °C (optimum, 35 °C), with pH 6.0-8.0 (optimum, pH 7.0) and 0-1.5% (W/V) NaCl (optimum, 1%). The predominant fatty acids (> 5%) in HNSRY-1T cells are iso-C15:0, C17:0, C17:1 ω8c, C16:0, and C16:1 ω6c/C16:1 ω7c. The major respiratory quinone is MK-8. The polar lipids are phosphatidylglycerol, phosphatidylethanolamine, three unidentified lipids and four unidentified aminolipids. The 16S rRNA gene sequence-based phylogenetic analysis indicated that strain HNSRY-1T belonged to the family Silvanigrellaceae, forming a distinct phylogenetic line distantly related (< 96.4% sequence similarity) to known species of the family. The ANI values of strain HNSRY-1T compared to the closely related species were below the determined genus division threshold limit (92-94% ANI), and AAI values were lower than the determined genus division threshold limit (80% AAI). Whole genome sequencing revealed a genome size of 3.63 Mb with a DNA G + C content at 29.6%. The half-lethal dose of strain HNSRY-1T on KM mice is about 1.12 × 108 CFU/ml. Virulence gene analysis showed that the pathogenicity of HNSRY-1T may be related to tufA, htpB, katA, wbtL, wbtM, pseB, clpP, cheY, cheV3, acpXL, pilB, fliN, ggt, flgG, fliP, nueB, pseA, bioB and flil. Based on these findings from the polyphasic taxonomy studies, a novel genus and species of the family Silvanigrellaceae. Pigmentibacter ruber gen. nov., sp. nov. is proposed, with type strain HNSRY-1T (= KCTC 72920T = CGMCC 1.18525T).