Ostreibacterium oceani gen. nov., sp. nov., isolated from oyster, and description of Ostreibacteriaceae fam. nov.

ABSTRACT

A novel Gram-stain-negative, short rod-shaped, facultatively anaerobic, non-motile, non-gliding, oxidase-positive and catalase-negative bacterium, designated ML27T, was isolated from oyster homogenate in Rushan, Weihai, PR China. Growth occurred at 20-33 °C (optimum, 30 °C), at pH 7.0-9.0 (optimum, pH 7.5-8.0) and in the presence of 1-6 % (w/v) NaCl (optimum, 3 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ML27T was 90.7 % similar to Suttonella ornithocola DSM 18249T, 89.2 % to Suttonella indologenes JCM 1478T and 88.2 % to Cardiobacterium hominis DSM 8339T; similarities to other species were less than 90 %. The average amino acid identity between strain ML27T, S. indologenes JCM 1478T, S. ornithocola DSM 18249T, C. hominis DSM 8339T and Dichelobacter nodosus ATCC 25549T were 46.23, 45.86, 45.54 and 45.84 %, respectively. Phylogenomic tree and phylogenetic analyses based on 16S rRNA gene sequences showed that the isolate formed a novel family-level clade in the order Cardiobacteriales. The sole respiratory quinone was ubiquinone-7 (Q-7). The dominant cellular fatty acids were summed feature 8 (C18  1 ω7c/C18  1 ω6c; 46.3 %), C16  0 (17.8 %) and summed feature 3 (C16  1 ω7c/C16  1 ω6c; 13.5 %). The DNA G+C content of strain ML27T was 45.6 mol%. Polar lipids included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and one unidentified lipid. Comparative analyses of 16S rRNA gene sequences, genomic distinctiveness and characterization indicated that strain ML27T represents a novel species of a new genus within a novel family of the order Cardiobacteriales, for which the name Ostreibacterium oceani gen. nov., sp. nov. is proposed. The type strain of Ostreibacterium oceani is ML27T (=MCCC 1H00372T=KCTC 72155T). In addition, a novel family, Ostreibacteriaceae fam. nov., is proposed to accommodate the genus Ostreibacterium.