Flavobacterium solisilvae sp. nov. and Flavobacterium silvaticum sp. nov., isolated from forest soil

Two Gram-stain-negative, yellow-pigmented and strictly aerobic bacteria, designated strains SE-s27^T and SE-s28^T, were isolated from forest soil. Both strains were non-motile rods that were catalase-positive and oxidase-negative and grew optimally at 25-30 °C, pH 8.0 and with 0 % (w/v) NaCl. Strain SE-s28^T produced flexirubin-type pigments, but strain SE-s27^T did not produce them. Both strains contained menaquinone-6 as the sole respiratory quinone and phosphatidylethanolamine as a major polar lipid. As the major cellular fatty acids (>10 %), SE-s27^T contained iso-C_15 : 1 and iso-C_15 : 1G, whereas SE-s28^T contained iso-C_15 : 0 and summed feature 3 comprising C_16 : 1ω7c and/or C_16 : 1ω6c and/or iso-C_15 : 0 2-OH. The DNA G+C contents of strains SE-s27^T and SE-s28^T were 33.1 and 44.3 mol%, respectively. The results of phylogenetic analysis based on 16S rRNA gene sequences revealed that SE-s27^T and SE-s28^T formed respective distinct phylogenetic lineages within the genus Flavobacterium. Strains SE-s27^T and SE-s28^T were most closely related to Flavobacterium macrobrachii an-8^T and Flavobacterium piscinae ICH-30^T with 98.0 and 94.5 % 16S rRNA gene sequence similarities, respectively. In conclusion, strains SE-s27^T and SE-s28^T represent novel species of the genus Flavobacterium, for which the names Flavobacterium solisilvae sp. nov. and Flavobacterium silvaticum sp. nov. are proposed. The type strains of F. solisilvae and F. silvaticum are SE-s27^T (=KACC 18802^T=JCM 31544^T) and SE-s28^T (=KACC 18803^T=JCM 31545^T), respectively.

Flavobacterium phycosphaerae sp. nov. isolated from the phycosphere of Microcystis aeruginosa

A novel aerobic bacterial strain, designated MK012^T, was isolated from the phycosphere of Microcystis aeruginosa. MK012^T appears to be Gram-stain-negative, non-motile and rod-shaped and has yellow pigments. Phylogenetic analysis using 16S rRNA revealed that this bacterium was most closely related to Flavobacterium buctense T7^T (=JCM 30750^T; 97.5 %), Flavobacterium dankookense ARSA-19^T (=KCTC 23179^T; 97.5 %) and Flavobacterium macrobrachii an-8^T (=DSM 22219^T; 97.3 %). The genome size and genomic DNA G+C content of MK012^T were estimated at 3.3 Mbp and 37.6 mol%, respectively. The average nucleotide identity (ANI), average amino acid identity (AAI) and in silico DNA-DNA hybridization (dDDH) values of MK012^T and the members of the genus Flavobacterium were found to be 71.8-78.3 %, 65.1-79.6% and 19.1-21.5 %, respectively. MK012^T exhibited oxidase but no catalase activity. The cells grew at 14-36 °C (optimum, 25 °C), pH 5-10 (optimum, pH 7) and 0-0.4 % (w/v) NaCl (optimum, 0 % NaCl) in R2A medium. MK012^T did not produce flexirubin-type pigments. The predominant cellular fatty acids of MK012^T were determined to be iso-C_15 : 0, iso-C_15 : 0 3-OH, iso-C_17 : 0 3-OH, and summed feature 9 (10-methyl C_16 : 0 and/or iso-C_17 : 1ω9c); MK-6 was identified as its only respiratory quinone. Its major polar lipids were determined to be phosphatidylethanolamine, two unidentified aminolipids, and two unidentified polar lipids. The genotypic and phenotypic characteristics indicate that MK012^T (=KACC 21509^T=JCM 33879^T) represents a novel species of the genus Flavobacterium; therefore, the name Flavobacterium phycosphaerae sp. nov. is proposed.

Isolation and Characterization of Flavobacteriaceae from Farmed and Wild Nile Tilapia in Tanzania

The present study was conducted to explore the occurrence of Flavobacteriaceae in wild Nile Tilapia Oreochromis niloticus (n = 108) collected from Lake Victoria and farmed Nile Tilapia (n = 187) collected from 12 ponds in the Morogoro region of Tanzania. The size of the ponds surveyed ranged from 130 to 150 m² . Pond parameters and fish morphometric data were recorded during sampling. In total, 67 Flavobacterium-like isolates (n = 44 from farmed fish; n = 23 from wild fish) were identified on the basis of colony morphology and biochemical tests. Sequences from the 16S ribosomal RNA (rRNA) gene revealed that all 67 isolates belonged to the genera Flavobacterium and Chryseobacterium. Based on 16S rRNA nucleotide identity, 26 isolates showed high similarity with C. indologenes (99-100% identity), 16 showed similarity to C. joostei (98-99.9%), and 17 were similar to diverse species of Chryseobacterium (97-99%). Three isolates were similar to F. aquatile and three were similar to F. indicum, with 99-100% nucleotide identity in both cases, and two isolates were similar to F. oryzae (99-100% identity). The findings obtained in this study provide a baseline for future studies and contribute to an understanding of the threats presented by the aquatic Flavobacteriaceae reservoir toward the development of healthy fish farming in Tanzania. Such knowledge is vital for the development of a sustainable aquaculture industry in Tanzania that will contribute to increased food security.

Flavobacterium lutivivi sp. nov., isolated from activated sludge

A Gram-stain-negative, strictly aerobic, yellow, rod-shaped bacterium, designated strain HQQ^T, was isolated from a municipal wastewater treatment plant in Hebei Province, PR China. Comparative 16S rRNA gene sequence analyses showed that strain HQQ^T is a member of the genus Flavobacterium and is closely related to 'Flavobacterium shanxiense' CCTCC AB 2014079^T (94.8 %) and Flavobacterium macrobrachii DSM 22219^T (94.7 %). Phylogenetic analysis showed that strain HQQ^T clustered with Flavobacterium fontis JCM 18212^T and Flavobacterium squillarum KCTC 23915^T. The polar lipid profile of strain HQQ^T revealed the presence of phosphatidylethanolamine, six unknown aminolipids, one unknown glycolipid and one unknown lipid and the only isoprenoid quinone was MK-6. The dominant fatty acids of strain HQQ^T were iso-C_15 : 0, C_15 : 0 and C_16 : 1ω7c. The DNA G+C content of strain HQQ^T is 32 mol%. On the basis of the phylogenetic and phenotypic data, strain HQQ^T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium lutivivi sp. nov. is proposed. The type strain is HQQ^T ( = CGMCC 1.15347^T = KCTC 42935^T).

High quality draft genomic sequence of Flavobacterium enshiense DK69(T) and comparison among Flavobacterium genomes

Flavobacterium enshiense DK69(T) is a Gram-negative, aerobic, rod-shaped, non-motile and non-flagellated bacterium that belongs to the family Flavobacteriaceae in the phylum Bacteroidetes. The high quality draft genome of strain DK69(T) was obtained and has a 3,375,260 bp genome size with a G + C content of 37.7 mol % and 2848 protein coding genes. In addition, we sequenced five more genomes of Flavobacterium type strains and performed a comparative genomic analysis among 12 Flavobacterium genomes. The results show some specific genes within the fish pathogenic Flavobacterium strains which provide information for further analysis the pathogenicity.

Emerging flavobacterial infections in fish: A review

Flavobacterial diseases in fish are caused by multiple bacterial species within the family Flavobacteriaceae and are responsible for devastating losses in wild and farmed fish stocks around the world. In addition to directly imposing negative economic and ecological effects, flavobacterial disease outbreaks are also notoriously difficult to prevent and control despite nearly 100 years of scientific research. The emergence of recent reports linking previously uncharacterized flavobacteria to systemic infections and mortality events in fish stocks of Europe, South America, Asia, Africa, and North America is also of major concern and has highlighted some of the difficulties surrounding the diagnosis and chemotherapeutic treatment of flavobacterial fish diseases. Herein, we provide a review of the literature that focuses on Flavobacterium and Chryseobacterium spp. and emphasizes those associated with fish.

Flavobacterium oryzae sp. nov., isolated from a flooded rice field, and emended descriptions of Flavobacterium flevense, Flavobacterium yonginense and Flavobacterium myungsuense

A bacterial strain, designated Jyi-05T, was isolated from a flooded rice field and characterized using a polyphasic taxonomic approach. Cells of strain Jyi-05T were Gram-stain-negative, strictly aerobic, bright-yellow-pigmented rods that were motile by gliding. Growth occurred at 10–30 °C (optimum 30 °C), at pH 6.5–7.5 (optimum pH 7.0) and with 0–2 % (w/v) NaCl (optimum 1 %, w/v, NaCl). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Jyi-05T belonged to the genus Flavobacterium and was most closely related to Flavobacterium flevense DSM 1076T with sequence similarity of 97.6 %. Strain Jyi-05T contained iso-C15 : 0 (16.6 %), anteiso-C15 : 0 (10.8 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 10.3 %), iso-C17 : 0 3-OH (9.2 %), C16 : 0 (7.3 %) and iso-C15 : 0 3-OH (7.2 %) as the predominant fatty acids. The major isoprenoid quinone was MK-6. The polar lipid profile consisted of phosphatidylethanolamine and several uncharacterized aminophospholipids and phospholipids. The major polyamine was homospermidine. The genomic DNA G+C content of strain Jyi-05T was 34.2 mol%. The DNA–DNA relatedness of strain Jyi-05T with respect to recognized species of the genus Flavobacterium was less than 70 %. On the basis of the phylogenetic inference and phenotypic data, strain Jyi-05T should be classified as a novel species, for which the name Flavobacterium oryzae sp. nov. is proposed. The type strain is Jyi-05T ( = BCRC 80522T = LMG 27292T = KCTC 32240T). Emended descriptions of Flavobacterium flevense , Flavobacterium yonginense and Flavobacterium myungsuense are also presented.

Flavobacterium arsenitoxidans sp. nov., an arsenite-oxidizing bacterium from Thai soil

An arsenite-oxidizing bacterium, strain S2-3H(T), was isolated from arsenic-contaminated soil sample collected from Dantchaeng district, Suphanburi province, Thailand and was characterized based on polyphasic taxonomic study. The strain was observed to be a Gram-stain negative, aerobic, yellow pigmented, non-spore forming and rod-shaped bacterium. Major menaquinone was MK-6. Iso-C15:0, iso-C15:0 3OH, C16:1 ω7c/C16:1 ω6c, C16:0, iso-C17:0 3OH, and C16:0 3OH were the predominant cellular fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, unidentified phospholipids and unidentified aminophospholipids. The DNA G+C content was 37.0 mol%. Phylogenetic analysis using 16S rRNA sequence showed that strain S2-3H(T) is affiliated to the genus Flavobacterium, and is closely related to F. defluvii KCTC 12612(T) (97.0 %) and F. johnsoniae NBRC 14942(T) (97.0 %). The strain S2-3H(T) could be clearly distinguished from the related Flavobacterium species by its physiological and biochemical characteristics as well as its phylogenetic position and DNA-DNA relatedness. Therefore, the strain represents a novel species of the genus Flavobacterium, for which the name Flavobacterium arsenitoxidans sp. nov. (type strain S2-3H(T) = KCTC 22507(T) = NBRC 109607(T) = PCU 331(T) = TISTR 2238(T)) is proposed.

Flavobacterium plurextorum sp. nov. Isolated from Farmed Rainbow Trout (Oncorhynchus mykiss)

Five strains (1126-1H-08^T, 51B-09, 986-08, 1084B-08 and 424-08) were isolated from diseased rainbow trout. Cells were Gram-negative rods, 0.7 µm wide and 3 µm long, non-endospore-forming, catalase and oxidase positive. Colonies were circular, yellow-pigmented, smooth and entire on TGE agar after 72 hours incubation at 25°C. They grew in a temperature range between 15°C to 30°C, but they did not grow at 37°Cor 42°C. Based on 16S rRNA gene sequence analysis, the isolates belonged to the genus Flavobacterium. Strain 1126-1H-08^T exhibited the highest levels of similarity with Flavobacterium oncorhynchi CECT 7678^T and Flavobacterium pectinovorum DSM 6368^T (98.5% and 97.9% sequence similarity, respectively). DNA–DNA hybridization values were 87 to 99% among the five isolates and ranged from 21 to 48% between strain 1126-1H-08^T, selected as a representative isolate, and the type strains of Flavobacterium oncorhynchi CECT 7678^T and other phylogenetic related Flavobacterium species. The DNA G+C content of strain 1126-1H-08^T was 33.2 mol%. The predominant respiratory quinone was MK-6 and the major fatty acids were iso-C_15∶0 and C_15∶0. These data were similar to those reported for Flavobacterium species. Several physiological and biochemical tests differentiated the novel bacterial strains from related Flavobacterium species. Phylogenetic, genetic and phenotypic data indicate that these strains represent a new species of the genus Flavobacterium, for which the name Flavobacterium plurextorum sp. nov. was proposed. The type strain is 1126-1H-08^T ( = CECT 7844^T = CCUG 60112^T).

Flavobacterium squillarum sp. nov., isolated from a freshwater shrimp culture pond, and emended descriptions of Flavobacterium haoranii , Flavobacterium cauense , Flavobacterium terrae and Flavobacterium aquatile

A bacterial strain, designated CMJ-5T, was isolated from a freshwater shrimp culture pond in Taiwan and characterized using a polyphasic taxonomic approach. Cells of strain CMJ-5T were Gram-stain-negative, strictly aerobic, non-motile, yellow-pigmented rods surrounded by a thick capsule. Growth occurred at 20–35 °C (optimum, 30 °C), at pH 6.5–8.0 (optimum, pH 7.0) and with 0–0.5 % NaCl (optimum, 0 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain CMJ-5T belonged to the genus Flavobacterium and was related most closely to Flavobacterium haoranii LQY-7T with sequence similarity of 94.4 %. Strain CMJ-5T contained iso-C15 : 0 (37.5 %), iso-C17 : 0 3-OH (13.4 %), iso-C15 : 0 3-OH (13.1 %) and iso-C15 : 1 G (11.2 %) as the predominant fatty acids. The major isoprenoid quinone was MK-6. The polar lipid profile consisted of phosphatidylethanolamine and several uncharacterized aminophospholipids and phospholipids. The major polyamine was homospermidine. The G+C content of the genomic DNA was 42.4 mol%. On the basis of phylogenetic inference and phenotypic data, strain CMJ-5T should be classified as a representative of a novel species, for which the name Flavobacterium squillarum sp. nov. is proposed. The type strain is CMJ-5T ( = BCRC 80405T = LMG 26890T = KCTC 23915T). Emended descriptions of Flavobacterium haoranii , Flavobacterium cauense , Flavobacterium terrae and Flavobacterium aquatile are also proposed.

Flavobacterium aciduliphilum sp. nov., isolated from freshwater, and emended description of the genus Flavobacterium

A Gram-stain-negative, rod-shaped, non-motile and yellow-pigmented bacterial strain, designated strain JJ013T, was isolated from an artificial lake in Jeollabuk-do, South Korea, and characterized using a polyphasic approach. The 16S rRNA gene sequence of strain JJ013T indicated that the isolate belonged to the family Flavobacteriaceae and exhibited similarity levels of 96.6 % to the type strains of Flavobacterium cheonanense and Flavobacterium koreense and 96.5 % to the type strain of Flavobacterium chungnamense . Growth was observed at 20–30 °C and pH 5.0–7.0. The major cellular fatty acids of the novel strain were iso-C15 : 0 (27.5 %), iso-C15 : 1 G (17.8 %), iso-C17 : 0 3-OH (9.4 %) and iso-C15 : 0 3-OH (9.2 %). Flexirubin-type pigments were present. The DNA G+C content of strain JJ013T was 33.9 mol%, the major respiratory quinone was menaquinone-6 (MK-6) and the major polyamine was sym-homospermidine. The polar lipid profile of the strain JJ013T consisted of a phosphatidylethanolamine (PE), two unknown aminolipids (AL1–2), three unidentified lipid (L1–3) and an unknown glycolipid (GL). On the basis of the morphological and physiological properties and biochemical evidence presented, it is concluded that strain JJ013T represents a novel species of the genus Flavobacterium , for which the name Flavobacterium aciduliphilum sp. nov. is proposed; the type strain is JJ013T ( = KACC 16594T = JCM 18211T). Since C15 : 0, which is known as a predominant fatty acid of the genus Flavobacterium was not detected in the novel strain and other reference strains, we propose an emended description of the genus Flavobacterium .

Flavobacterium enshiense sp. nov., isolated from soil, and emended descriptions of the genus Flavobacterium and Flavobacterium cauense , Flavobacterium saliperosum and Flavobacterium suncheonense

A Gram-negative, strictly aerobic, yellow-pigmented rod, designated DK69T, was isolated from soil collected from the waste liquid treatment facility of Bafeng Pharmaceutical Company in the city of Enshi, Hubei Province, China. Phylogenetic analysis based on 16S rRNA gene sequences placed strain DK69T in the genus Flavobacterium of the family Flavobacteriaceae . The highest 16S rRNA gene sequence similarities were found with Flavobacterium cauense R2A-7T (96.9 %), Flavobacterium saliperosum AS 1.3801T (96.3 %) and Flavobacterium suncheonense GH29-5T (95.7 %). The major fatty acids (≥5 %) were iso-C15 : 0, iso-C17 : 1ω9c, C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 0 3-OH. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid. The major respiratory quinone was menaquinone-6. The genomic DNA G+C content was 34.4 mol%. Strain DK69T represents a novel species of the genus Flavobacterium , for which the name Flavobacterium enshiense sp. nov. is proposed. The type strain is DK69T ( = CCTCC AB 2011144T  = KCTC 23775T). Emended descriptions of the genus Flavobacterium and Flavobacterium cauense , Flavobacterium saliperosum and Flavobacterium suncheonense are also proposed.

Flavobacterium dankookense sp. nov., isolated from a freshwater reservoir, and emended descriptions of Flavobacterium cheonanense , F. chungnamense , F. koreense and F. aquatile

A novel yellow-pigmented bacterial strain, designated ARSA-19T, 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-19T belonged to the genus Flavobacterium and was related to Flavobacterium macrobrachii an-8T (96.5 % sequence similarity), F. koreense KACC 14969T (96.2 %), F. chungnamense KACC 14971T (96.1 %), F. cheonanense KACC 14972T (96.4 %) and F. aquatile ATCC 11947T (95.6 %). The isolate contained MK-6 as the predominant menaquinone and iso-C15 : 0 (21.8 %), iso-C16 : 0 3-OH (10.4 %), iso-C15 : 1 G (9.3 %), summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c; 8.2 %), iso-C15 : 0 3-OH (7.7 %) and iso-C16 : 0 (7.3 %) as the major fatty acids. The polar lipids of strain ARSA-19T were phosphatidylethanolamine, four unknown aminolipids and two unidentified polar lipids. The DNA G+C content of strain ARSA-19T was 33.3 mol%. Based on its phenotypic and genotypic characteristics and on the phylogenetic evidence presented, strain ARSA-19T 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-19T ( = KCTC 23179T  = JCM 17065T  = KACC 14968T). Emended descriptions of Flavobacterium cheonanense , Flavobacterium chungnamense , Flavobacterium koreense and Flavobacterium aquatile are also proposed.

Flavobacterium compostarboris sp. nov., isolated from leaf-and-branch compost, and emended descriptions of Flavobacterium hercynium , Flavobacterium resistens and Flavobacterium johnsoniae

A strictly aerobic, Gram-negative, yellow-pigmented, non-spore-forming rod, designated 15C3T, was isolated from aerobic leaf-and-branch compost at EXPO Park in Osaka, Japan. Growth was observed at 9–33 °C (optimum 25 °C) and pH 5.6–7.9 (optimum pH 6.1–7.0). No growth occurred with >2 % (w/v) NaCl. Strain 15C3T reduced nitrate to nitrogen and showed catalase activity but not oxidase activity. The predominant fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c and/or iso-C15 : 0 2-OH). The isolate contained phosphatidylethanolamine as the major polar lipid and menaquinone-6 as the major respiratory quinone. The G+C content of the genomic DNA of strain 15C3T was 33.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 15C3T belonged to the genus Flavobacterium and was most closely related to Flavobacterium hercynium WB 4.2-33T (96.9 % sequence similarity). On the basis of phenotypic and phylogenetic distinctiveness, strain 15C3T is considered to represent a novel species in the genus Flavobacterium , for which the name Flavobacterium compostarboris sp. nov. is proposed. The type strain is 15C3T ( = KACC 14224T  = JCM 16527T). Emended descriptions of F. hercynium , Flavobacterium resistens and Flavobacterium johnsoniae are also given.

Flavobacterium rakeshii sp. nov., isolated from marine sediment, and emended description of Flavobacterium beibuense Fu et al. 2011

A Gram-negative, non-motile bacterial strain that formed straight rods and straw yellow colonies, designated FCS-5(T), was isolated from a marine sediment from the Arabian Sea. The isolate exhibited most of the phenotypic properties expected for a member of the genus Flavobacterium. The major fatty acids were iso-C(15:0), iso-C(17:0) 3-OH, C(17:1)ω9c and summed feature 3 (comprising iso-C(15:0) 2-OH and/or C(16:1)ω7c). The only isoprenoid quinone was MK-6. The only polyamine was homospermidine and the major polar lipid was phosphatidylethanolamine. The G+C content of the genomic DNA was 32.4 mol%. According to 16S rRNA gene sequence analysis, strain FCS-5(T) belonged to the genus Flavobacterium and exhibited 99.3% 16S rRNA gene sequence similarity with Flavobacterium beibuense F44-8(T) and 90.9-94.6% sequence similarity with other members of the genus Flavobacterium. The results of physiological and biochemical tests allowed the discrimination of the isolate from its phylogenetic relatives. Strain FCS-5(T) is a representative of a novel species of the genus Flavobacterium, for which the name Flavobacterium rakeshii sp. nov. is proposed. The type strain is FCS-5(T) ( = MTCC 10967(T) = JCM 17928(T)). An emended description of F. beibuense is also proposed.