We report here the draft whole-genome sequences for 18 Flavobacterium species type strains that have historically been associated with fish gill disease.

The bacterial phylum Bacteroidetes, characterized by a distinct gliding motility, occurs in a broad variety of ecosystems, habitats, life styles, and physiologies. Accordingly, taxonomic classification of the phylum, based on a limited number of features, proved difficult and controversial in the past, for example, when decisions were based on unresolved phylogenetic trees of the 16S rRNA gene sequence. Here we use a large collection of type-strain genomes from Bacteroidetes and closely related phyla for assessing their taxonomy based on the principles of phylogenetic classification and trees inferred from genome-scale data. No significant conflict between 16S rRNA gene and whole-genome phylogenetic analysis is found, whereas many but not all of the involved taxa are supported as monophyletic groups, particularly in the genome-scale trees. Phenotypic and phylogenomic features support the separation of Balneolaceae as new phylum Balneolaeota from Rhodothermaeota and of Saprospiraceae as new class Saprospiria from Chitinophagia. Epilithonimonas is nested within the older genus Chryseobacterium and without significant phenotypic differences; thus merging the two genera is proposed. Similarly, Vitellibacter is proposed to be included in Aequorivita. Flexibacter is confirmed as being heterogeneous and dissected, yielding six distinct genera. Hallella seregens is a later heterotypic synonym of Prevotella dentalis. Compared to values directly calculated from genome sequences, the G+C content mentioned in many species descriptions is too imprecise; moreover, corrected G+C content values have a significantly better fit to the phylogeny. Corresponding emendations of species descriptions are provided where necessary. Whereas most observed conflict with the current classification of Bacteroidetes is already visible in 16S rRNA gene trees, as expected whole-genome phylogenies are much better resolved.

A novel yellow-pigmented bacterial strain, designated ARSA-19(T), was isolated from a freshwater reservoir in Cheonan, Korea. Cells were Gram-staining-negative, rod-shaped, strictly aerobic and positive for catalase and oxidase. The phylogenetic tree based on 16S rRNA gene sequences showed that strain ARSA-19(T) belonged to the genus Flavobacterium and was related to Flavobacterium macrobrachii an-8(T) (96.5% sequence similarity), F. koreense KACC 14969(T) (96.2%), F. chungnamense KACC 14971(T) (96.1%), F. cheonanense KACC 14972(T) (96.4%) and F. aquatile ATCC 11947(T) (95.6%). The isolate contained MK-6 as the predominant menaquinone and iso-C(15:0) (21.8%), iso-C(16:0) 3-OH (10.4%), iso-C(15:1) G (9.3%), summed feature 3 (iso-C(15:0) 2-OH and/or C(16:1)�s7c; 8.2%), iso-C(15:0) 3-OH (7.7%) and iso-C(16:0) (7.3%) as the major fatty acids. The polar lipids of strain ARSA-19(T) were phosphatidylethanolamine, four unknown aminolipids and two unidentified polar lipids. The DNA G+C content of strain ARSA-19(T) was 33.3 mol%. Based on its phenotypic and genotypic characteristics and on the phylogenetic evidence presented, strain ARSA-19(T) is considered to represent a novel species in the genus Flavobacterium, for which the name Flavobacterium dankookense sp. nov. is proposed. The type strain is ARSA-19(T) (= KCTC 23179(T) = JCM 17065(T) = KACC 14968(T)). Emended descriptions of Flavobacterium cheonanense, Flavobacterium chungnamense, Flavobacterium koreense and Flavobacterium aquatile are also proposed.