Abstract

A Gram-staining-negative non endospore-forming strain, T13(2019)(T) was isolated from water samples from Atlantic salmon (Salmo salar) fry culture in Chile and studied in detail for its taxonomic position. The isolate shared highest 16S rRNA gene sequence similarities with the type strains of Flavobacterium chungangense (98.44%) followed by Flavobacterium tructae and Flavobacterium spartansii (both 98.22%). Menaquinone MK-6 was the predominant respiratory quinone in T13(2019)(T). Major polar lipids were phosphatidylethanolamine, an ornithine lipid and the unidentified polar lipids L1, L3 and L4 lacking a functional group. The major polyamine was sym-homospermidine. The fatty acid profile contained major amounts of iso-C-15:0, iso-C (15:0) 3-OH, iso-C-17:0 3-OH, C-15:0, summed feature 3 (C-16:1 omega 7c and/or iso-C-15:0 2-OH) and various hydroxylated fatty acids in smaller amounts, among them iso-C-16:0 3-OH, and C-15:0 3-OH, which supported the grouping of the isolate into the genus Flavobacterium. Physiological/biochemical characterisation and ANI calculations with the type strains of the most closely related species allowed a clear phenotypic and genotypic differentiation. In addition it became obvious, that the type strains of F. tructae and F. spartansii showed 100% 16S rRNA gene sequence similarities and ANI values of 97.21%/ 97.59 % and DDH values of 80.40 % [77.5 and 83%]. These data indicate that F. tructae and F. spartansii belong to the same species and it is proposed that F. spartansii is a later heterotypic synonym of F. tructae. For strain T13(2019)(T) (=CIP 111411(T)=LMG 30298(T)=CCM 8798(T)) a new species with the name Flavobacterium salmonis sp. nov. is proposed.