Dentiradicibacter hellwigii gen. nov., sp. nov., isolated from a secondary infected root canal in the human oral cavity

A motile, rod-shaped and anaerobic strain WK13^T was isolated from a secondary root canal infection of a human tooth. WK13^T cells were Gram-stain-negative, catalase-positive and oxidase-negative. The major fatty acids (≥ 5.0%) were C_{16 : 0}, C_{18 : 0}, C_{16 : 1} <i> ω</i>7c, C_{18 : 1} <i> ω</i>9c and C_{18 : 2} <i> ω</i>6,9c. The DNA G+C content was 57.94 mol%. The major polar lipids were phosphatidylethanolamine, phosphatidylserine, diphosphatidylglycerol, phosphatidylcholine and lysophosphatidylcholine. There were no respiratory quinones detectable. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain WK13^T belongs to the class <i>Betaproteobacteria</i>. WK13^T showed a 93.6% and 93.5% 16S rRNA gene sequence similarity to the most closely related cultured species, <i>Propionivibrio pelophilus</i> strain DSM 12018^T and <i>Propionivibrio dicarboxylicus</i> strain DSM 5885^T, respectively. On the basis of physiological and biochemical data, the isolate is considered to represent a novel species of a new genus in the class <i>Betaproteobacteri</i>a, for which we propose the name <i>Dentiradicibacter hellwigii</i> gen. nov., sp. nov. The type strain is WK13^T (=DSM 112713^T=NCTC 14938^T).