Flavobacterium chilense sp. nov. and Flavobacterium araucananum sp. nov., isolated from farmed salmonid fish

Abstract

Three Gram-staining-negative non-endospore-forming strains were isolated from farmed fish in Chile: one (LM-09-FpT) from a rainbow trout (Oncorhynchus mykiss) and the others (LM-19-FpT and LM-20-Fp) from two Atlantic salmon (Salmo salar). Phylogenetic analyses based on 16S rRNA gene sequences indicated that all three isolates belonged to the genus Flavobacterium . In these analyses, strain LM-09-FpT appeared most closely related to the type strains of Flavobacterium chungangense (98.5 % sequence similarity), Flavobacterium glaciei (98.2 %), Flavobacterium aquidurense (97.6 %), Flavobacterium saccharophilum (97.6 %) and Flavobacterium hercynium (97.6 %). The 16S rRNA gene sequences of strains LM-19-FpT and LM-20-Fp were found to be identical and most similar to the corresponding sequences of the type strains of Flavobacterium aquidurense (98.6 %), Flavobacterium frigidimaris (98.5 %), Flavobacterium hercynium (97.9 %), Flavobacterium saccharophilum (97.7 %) and Flavobacterium pectinovorum (97.7 %). For each of the three novel strains, menaquinone (MK-6) was the predominant respiratory quinone and the major compounds in the polar lipid profile were phosphatidylethanolamine, an unidentified aminolipid, phosphatidylserine and two or three unknown lipids. The fatty acid profile of each strain, which comprised major amounts of iso-C15 : 0, C15 : 0 and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) as well as smaller amounts of various hydroxylated fatty acids (e.g. iso-C16 : 0 3-OH, iso-C17 : 0 3-OH, C16 : 0 3-OH and C15 : 0 3-OH), indicated that each belonged to the genus Flavobacterium . Based on their physiological and biochemical characteristics and the results of DNA–DNA hybridizations, which showed relatively low levels of relatedness between the novel strains and the most closely related Flavobacterium species, strain LM-09-FpT ( = LMG 26360T = CCM 7940T) represents a novel species within the genus Flavobacterium , for which the name Flavobacterium chilense sp. nov. is proposed, and strains LM-19-FpT ( = LMG 26359T = CCM 7939T) and LM-20-Fp ( = LMG 26331) represent a second novel species within the same genus, for which the name Flavobacterium araucananum sp. nov. is proposed.