Flavobacterium ichthyis sp. nov., isolated from a fish pond

Bacterial strain NST-5(T), isolated from a fish pond in Taiwan, was characterized using a polyphasic taxonomy approach. Results of phylogenetic analyses based on 165 rRNA gene sequences and coding sequences of 92 protein clusters indicated that strain NST-5(T) formed a phylogenetic lineage in the genus Flavobacterium. Analysis of 16S rRNA gene sequences showed that strain NST-5(T) showed the highest similarity to Flavobacterium enshiense DK69T (94.9%), Flavobacterium ahnfeltiae 10A1g 130(T) (94.8%) and Flavobacterium vireti THG-SM1(T) (94.8%). Strain NST-5(T) showed 68.9-72.5% average nucleotide identity and 19.1-23.7% digital DNA-DNA hybridization identity with the type strains of other close related Flavobacterium species. Cells of the strain were Gram-stain-negative, strictly aerobic, motile by gliding, rod-shaped and formed yellow colonies. Optimal growth occurred at 30 degrees C. pH 7 and with 0.5% NaCl. Strain NST-5(T) contained iso-C-15(:0), C-15:0 and iso-C-16:0 as the predominant fatty acids. The major hydroxyl fatty acids were iso-C-16:0 3-OH and iso-C-17:0 3-OH. The polar lipid profile consisted of phosphatidylethanolamine, three uncharacterized aminophospholipids. two uncharacterized phospholipids and one uncharacterized aminolipid. The major polyamine was homospermidine. The major isoprenoid quinone was MK-6. The DNA G+C content of the genomic DNA was 35.5 mol%. Differential phenotypic properties, together with the phylogenetic inference, demonstrate that strain NST-5(T) should be classified as a novel species of the genus Flavobacterium, for which the name Flavobacterium ichthyis sp. nov. is proposed. The type strain is NST-5(T) (=BCRC 81198(T)=LMG 31341(T)).