A Gram-staining-negative, non-motile, curved rod-shaped, aerobic bacterium, designated S1-2-4T, was isolated from soil in Jeollabuk-do province, Republic of Korea, and was characterized taxonomically using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain S1-2-4T was a member of the family Cytophagaceae and most closely related to 'Spirosoma radiotolerans' DG5A (97.2%), Spirosoma fluviale MSd3T (96.4%), and Spirosoma linguale DSM 74T (96.3%). The genomic DNA G + C content of strain S1-2-4T was 49.7 mol%. The major fatty acids were summed feature 3 (C16:1 ω7c/C16:1 ω6c), C16:1 ω5c, and C16:0, and the major polar lipid was phosphatidylethanolamine. MK-7 was the predominant respiratory quinone. Phenotypic and chemotaxonomic data supported the affiliation of strain S1-2-4T with the genus Spirosoma. DNA-DNA hybridization between strain S1-2-4T and 'Spirosoma radiotolerans' showed relatively low DNA-DNA relatedness (31%). Strain S1-2-4T could be distinguished from its closest phylogenetic neighbors based on its phenotypic, genotypic, and chemotaxonomic features. Therefore, strain S1-2-4T represents a novel member of the genus Spirosoma, for which the name Spirosoma lituiforme sp. nov. is proposed. The type strain is S1-2-4T (= KCTC 52724T = JCM 32128T).
Keywords: Cytophagaceae; Spirosoma; polyphasic taxonomy.