Flavobacterium lotistagni sp. nov. and Flavobacterium celericrescens sp. nov., isolated from freshwater habitats

Flavobacterium psychraquaticum sp. nov., isolated from water system of Atlantic salmon (Salmo salar) smolts cultured in Chile

Strain LB-N7T, a novel Gram-negative, orange, translucent, gliding, rod-shaped bacterium, was isolated from water samples collected from an open system of Atlantic salmon (Salmo salar) smolts in a fish farm in Chile during a flavobacterial infection outbreak in 2015. Phylogenetic analysis based on 16S rRNA sequences (1337 bp) revealed that strain LB-N7T belongs to the genus Flavobacterium and is closely related to the type strains Flavobacterium ardleyense A2-1T (98.8 %) and Flavobacterium cucumis R2A45-3T (96.75 %). The genome size of strain LB-N7T was 2.93 Mb with a DNA G+C content 32.6 mol%. Genome comparisons grouped strain LB-N7T with Flavobacterium cheniae NJ-26T, Flavobacterium odoriferum HXWNR29T, Flavobacterium lacisediminis TH16-21T and Flavobacterium celericrescens TWA-26T. The calculated digital DNA-DNA hybridization values between strain LB-N7T and the closest related Flavobacterium strains were 23.3 % and the average nucleotide identity values ranged from 71.52 to 79.39 %. Menaquinone MK-6 was the predominant respiratory quinone, followed by MK-7. The major fatty acids were iso-C15 : 0 and anteiso-C15 : 0. The primary polar lipids detected included nine unidentified lipids, two amounts of aminopospholipid and phospholipids, and a smaller amount of aminolipid. Phenotypic, genomic, and chemotaxonomic data suggest that strain LB-N7T (=CECT 30406T=RGM 3221T) represents as a novel bacterial species, for which the name Flavobacterium psychraquaticum sp. nov. is proposed.

Flavobacterium potami sp. nov., a multi-metal resistance genes harbouring bacterium isolated from shallow river silt

Environmental pollution by heavy metals is becoming an increasing problem and has become a matter of great concern due to the adverse effects worldwide. In this study, we report a novel strain of multi-metal resistant bacteria. A Gram-stain-negative, strictly aerobic, non-motile, yellow, rod-shaped strain 17A^T, was isolated from the shallow silt of Fuyang River located in Longdian town, Hengshui city, Hebei province, China. Strain 17A^T grew at 20-35 °C (optimum, 30 °C), pH 5-10 (optimum, pH 7) and 0-2% (w/v) NaCl (optimum, 1%). Phylogenetic analyses of 16S rRNA gene sequences showed that strain 17A^T was closely related to members of the genus Flavobacterium, and had the highest 16S rRNA gene sequence similarity with 'Flavobacterium panacis' DCY106^T (97.5%), followed by Flavobacterium johnsoniae subsp. johnsoniae UW101^T (97.3%), Flavobacterium cutihirudinis E89^T (97.2%), Flavobacterium limi THG-AG6.4^T (97.2%), Flavobacterium hibisci THG-HG1.4^T (97.2%) and Flavobacterium johnsoniae subsp. aurantiacum DSM 6792^T (97.1%). The genome size of strain 17A^T was 5.4 Mb and the DNA G + C content was 34.0%. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values among strain 17A^T and reference strains were in the ranges of 79.8-86.1%, 24.1-31.4% and 80.5-88.6%, respectively, lower than the threshold values for species delineation. Strain 17A^T contained iso-C_15:0 and C_16:0 3-OH as the predominant fatty acids (≥ 10%). The main isoprenoid quinone of strain 17A^T was identified as MK-6. The polar lipids consisted of phosphatidylethanolamine, three unidentified aminolipids, two unidentified aminophospholipids and six unidentified lipids. Comparative genomics analysis between strain 17A^T and its reference type strains revealed that there are a number of metal-resistant genes in strain 17A^T, which are located in 15 gene clusters responsible for the copper homeostasis, cobalt-zinc-cadmium resistance, copper resistance, and arsenic/antimony resistance, with the copper resistance protein NlpE being unique to 17A^T. Combined data from phenotypic, phylogenetic and chemotaxonomic studies demonstrated that strain 17A^T is a representative of a novel species within the genus Flavobacterium, for which the name Flavobacterium potami sp. nov. is proposed. The type strain is 17A^T (= GDMCC 1.2723^T = JCM 34833^T).

Flavobacterium taihuense sp. nov., a bacterium isolated from lake sediment

A novel bacterium, designated NAS39T, was isolated from the interfacial sediment of Taihu Lake in PR China and its taxonomic position was investigated by using a polyphasic approach. Cells of the isolate were Gram-stain-negative, aerobic, non-motile, catalase-positive, yellow and rod-shaped. Phylogenetic analyses based on 16S rRNA gene sequences supported that strain NAS39T formed a cluster within the genus Flavobacterium , and was most closely related to Flavobacterium laiguense LB2P30T (98.4 %), followed by Flavobacterium tiangeerense 0563T (97.4 %). The average nucleotide identity values between strain NAS39T and F. laiguense LB2P30T and F. tiangeerense 0563T were 82.5 and 75.3 %, respectively. The digital DNA–DNA hybridization values between strain NAS39T and F. laiguense LB2P30T and F. tiangeerense 0563T were 40.9 and 18.6 %, respectively. The genomic DNA G+C content was 34.1 mol%. The major respiratory quinone was menaquinone-6. The dominant cellular fatty acids were iso-C15 : 0 and summed feature 3 comprising C16 : 1 ω7c/C16 : 1 ω6c. The polar lipids comprised phosphatidyl ethanolamine, two amino lipids, three amino phospholipids and two unidentified lipids. Based on the phenotypic, chemotaxonomic, genotypic and phylogenetic characteristics, strain NAS39T (=MCCC 1K06094T=KACC 22328T) represents a novel species of the genus Flavobacterium , for which the name Flavobacterium taihuense sp. nov. is proposed.