Chryseobacterium luteum sp. nov., associated with the phyllosphere of grasses

Genome analysis deciphered Chryseobacterium indicum is a distinct species associated with freshwater pufferfish

A bacterium, strain PS-8T of the genus Chryseobacterium, was isolated from the skin of freshwater pufferfish (Tetraodon cutcutia). Strain PS-8T is a Gram-negative, aerobic, non-motile, and rod-shaped bacterium. Colonies appear in yellowish-orange colors. The major cellular fatty acids were C15:0 iso, C17:0 iso 3OH, C15:0 iso 3OH, and C11:0 anteiso. The predominant polar lipids were phosphatidylethanolamine and amino lipids. The genome size is 4.83 Mb. The G + C content was 35.6%. The in silico dDDH homology, ANI, and AAI were below the cutoff value, 70% and 95% to 96%, respectively, suggesting that strain PS-8T represents a defined species. The phylogenetic tree based on core and the non-recombinant genes showed the strain PS-8T clustered with Chryseobacterium gambrini DSM 18014T. Genome-wide analysis decodes several virulence factors of the genus Chryseobacterium, including genes for adherence, biofilm and stability, proliferation, resistance to immune response, and host-defense evasion system. The cladogram of the virulence genes showed a phylogenetic relationship among the Chryseobacterium species. Knowledge of the association of Chryseobacterium with freshwater pufferfish adds a new ecological niche to this bacterium.

Pathogenic Potential and Control of Chryseobacterium Species from Clinical, Fish, Food and Environmental Sources

Chryseobacterium species are isolated and taxonomically evaluated from a wide range of sources. While C. gleum and C. indologenes have been implicated in human disease, the potential pathogenicity of numerous other species have not been investigated. The aims were therefore to evaluate 37 Chryseobacterium species and Elizabethkingia meningoseptica from environmental, food, fish, water and clinical sources for production of haemolysis, growth at 37 °C, and production of virulence enzymes. The control of these strains were investigated by determination of antimicrobial and disinfectant resistance. All the species produced α- or β-haemolysis. In terms of growth at 37 °C and production of virulence enzymes, C. soldanellicola (environmental), C. oranimense (food) and C. koreense (natural mineral water) could be potential human pathogens. Chryseobacterium piscium might be pathogenic to fish. Trimethoprim could be the most effective antimicrobial for the treatment of a Chryseobacterium species infection, while the disinfectants that contain poly-dimethyl ammonium chloride or benzalkonium chloride could be regarded as the most effective for decontamination of surfaces contaminated with Chryseobacterium species.

Exploring novel bacterial terpene synthases

Terpenes are the largest class of natural products with extensive structural diversity and are widely used as pharmaceuticals, herbicides, flavourings, fragrances, and biofuels. While they have mostly been isolated from plants and fungi, the availability and analysis of bacterial genome sequence data indicates that bacteria also possess many putative terpene synthase genes. In this study, we further explore this potential for terpene synthase activity in bacteria. Twenty two potential class I terpene synthase genes (TSs) were selected to represent the full sequence diversity of bacterial synthase candidates and recombinantly expressed in E. coli. Terpene synthase activity was detected for 15 of these enzymes, and included mono-, sesqui- and diterpene synthase activities. A number of confirmed sesquiterpene synthases also exhibited promiscuous monoterpene synthase activity, suggesting that bacteria are potentially a richer source of monoterpene synthase activity then previously assumed. Several terpenoid products not previously detected in bacteria were identified, including aromandendrene, acora-3,7(14)-diene and longiborneol. Overall, we have identified promiscuous terpene synthases in bacteria and demonstrated that terpene synthases with substrate promiscuity are widely distributed in nature, forming a rich resource for engineering terpene biosynthetic pathways for biotechnology.

Phylogenetic insights into the diversity of Chryseobacterium species

The genus Chryseobacterium was formally established in 1994 and contains 112 species with validly published names. Most of these species are yellow or orange coloured, and contain a flexirubin-type pigment. The genomes of 83 of these 112 species have been sequenced in view of their importance in clinical microbiology and potential applications in biotechnology. The National Center for Biotechnology Information taxonomy browser lists 1415 strains as members of the genus Chryseobacterium, of which the genomes of 94 strains have been sequenced. In this study, by comparing the 16S rDNA and the deduced proteome sequences, at least 20 of these strains have been proposed to represent novel species of the genus Chryseobacterium. Furthermore, a yellow-coloured bacterium isolated from dry soil in the USA (and identified as Flavobacterium sp. strain B-14859) has also been reconciled as a novel member of the genus Chryseobacterium based on the analysis of 16S rDNA sequences and the presence of flexirubin. Yet another bacterium (isolated from a water sample collected in the Western Ghats of India and identified as Chryseobacterium sp. strain WG4) was also found to represent a novel species. These proposals need to be validated using polyphasic taxonomic approaches.

Description of Chryseobacterium timonianum sp. nov., isolated from a patient with pneumonia

Using a polyphasic taxonomic strategy, an aerobic, Gram-negative, non-motile, yellow pigmented rod isolated from a sputum sample of a patient with pneumonia was characterised. This bacterial strain, designated G972^T, could not be identified by our systematic MALDI-TOF screening on a MicroFlex. This led to the sequencing of the 16S rRNA gene, which shows 98.57% sequence identity with that of Chryseobacterium indologenes 16777^T, the phylogenetic closely related type strain of a species with standing in nomenclature, which putatively classifies it as a new species. The major cell fatty acids were identified as 13-methyl-tetradecanoic acid (61%), 3-hydroxy-heptadecanoic acid (16%) and 15-methyl-11-hexadecenoic acid (11%). D-glucose, D-mannose, aesculin, D-maltose, D-trehalose, and gentibiose are the main carbon source. Digital DNA-DNA hybridization (dDDH) estimation and average nucleotide identity values (ANI) of the strain G972^T against genomes of the type strains of related species ranged between 18.9 and 32.8% and between 71.46 and 83.61%, respectively, thus confirming again the new species status of the strain. Here, we describe the characteristics of this organism, complete genome sequence and annotation. The 5,390,132 bp size genome contains 4867 protein-coding genes, 89 RNAs (three genes are 5S rRNA, one gene is 16S rRNA, one gene is 23S rRNA and 84 tRNAs) with 35.51% GC content. Finally, on the basis of these polyphasic data, consisting of phenotypic and genomic analyses, we conclude that strain strain G972^T (= DSM 103388^T = CSUR P2233^T) represents a novel species for which we propose the name Chryseobacterium timonianum. The 16S rRNA and genome sequences are available in GenBank database under accession numbers LT161886 and FJVD00000000.

Genome-Based Taxonomic Classification of Bacteroidetes

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.

Specific amplification of bacterial DNA by optimized so-called universal bacterial primers in samples rich of plant DNA

Universal primers targeting the bacterial 16S-rRNA-gene allow quantification of the total bacterial load in variable sample types by qPCR. However, many universal primer pairs also amplify DNA of plants or even of archaea and other eukaryotic cells. By using these primers, the total bacterial load might be misevaluated, whenever samples contain high amounts of non-target DNA. Thus, this study aimed to provide primer pairs which are suitable for quantification and identification of bacterial DNA in samples such as feed, spices and sample material from digesters. For 42 primers, mismatches to the sequence of chloroplasts and mitochondria of plants were evaluated. Six primer pairs were further analyzed with regard to the question whether they anneal to DNA of archaea, animal tissue and fungi. Subsequently they were tested with sample matrix such as plants, feed, feces, soil and environmental samples. To this purpose, the target DNA in the samples was quantified by qPCR. The PCR products of plant and feed samples were further processed for the Single Strand Conformation Polymorphism method followed by sequence analysis. The sequencing results revealed that primer pair 335F/769R amplified only bacterial DNA in samples such as plants and animal feed, in which the DNA of plants prevailed.

Chryseobacterium arachidiradicis sp. nov., isolated from the geocarposphere (soil around the peanut) of very immature peanuts (Arachis hypogaea)

A yellow-pigmented bacterial strain, 91A-612(T), isolated from the geocarposphere (soil around the peanut) of very immature peanuts (Arachis hypogaea) in Alabama, USA, was studied for its taxonomic position. Cells of the isolate were rod-shaped and stained Gram-negative. A comparison of the 16S rRNA gene sequence with the sequences of the type strains of the most closely related species showed that the strain belongs to the genus Chryseobacterium, showing the highest sequence similarities to the type strains of Chryseobacterium molle (98.4%), C. pallidum (98.3%) and C. hominis (97.8%). The 16S rRNA gene sequence similarities to the type strains of all other species of the genus Chryseobacterium were below 97.0%. The fatty acid profile of strain 91A-612(T) consisted of the major fatty acids iso-C15 : 0, summed feature 3 (iso-C15 : 0 2-OH/C16 : 1ω7c) and iso-C17 : 0 3-OH. Major compounds in the polar lipid profile were phosphatidylethanolamine and several unidentified lipids, including two lipids that did not contain a sugar moiety, an amino group or a phosphate group (L3, L8), and an aminolipid (AL1). The quinone system was composed mainly of MK-6. The polyamine pattern contained sym-homospermidine as the major compound and moderate amounts of spermidine and spermine. DNA-DNA hybridizations between strain 91A-612(T) and the type strains of C. molle, C. pallidum and C. hominis resulted in relatedness values well below 70%. These data and the differentiating biochemical and chemotaxonomic properties showed that isolate 91A-612(T) represents a novel species of the genus Chryseobacterium, for which we propose the name Chryseobacterium arachidiradicis sp. nov. (type strain 91A-612(T) = LMG 27814(T)= CCM 8490(T) = CIP 110647(T)).

Chryseobacterium gallinarum sp. nov., isolated from a chicken, and Chryseobacterium contaminans sp. nov., isolated as a contaminant from a rhizosphere sample

Two yellow-pigmented bacterial strains (100T and C26T), showing 98.4 % 16S rRNA gene sequence similarity to each other and isolated from a chicken in Germany and as a contaminant from an agar plate of a rhizosphere sample in Alabama, were studied by using a polyphasic taxonomic approach. Cells of both isolates were rod-shaped and stained Gram-negative. A comparison of the 16S rRNA gene sequences of the two organisms with the sequences of the type strains of the most closely related species of the genus Chryseobacterium showed the highest sequence similarities of strains 100T and C26T to the type strains of Chryseobacterium joostei (respectively 97.5 and 98.2 %), C. viscerum (96.6, 97.8 %), C. gleum (97.1, 97.7 %), C. arthrosphaerae (97.3%, 97.7 %), C. indologenes (97.2, 97.7 %), C. tructae (96.6, 97.6 %), C. jejuense (97.0, 97.6 %) and C. oncorhynchi (96.3, 97.5 %); 16S rRNA gene sequence similarities to members of all other species of the genus Chryseobacterium were below 97.5 %. The fatty acid profiles of both strains consisted of the major fatty acids iso-C15 : 0, summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c), iso-C17 : 1ω9c and iso-C17 : 0 3-OH, but also showed slight differences (absence or presence of C16 : 0 3-OH and iso-C15 : 1 F). DNA–DNA hybridizations between the two strains and between the novel strains and the type strains of C. joostei , C. indologenes , C. jejuense , C. tructae and C. viscerum resulted in relatedness values clearly below 70 %. These DNA–DNA hybridization results and the differentiating biochemical and chemotaxonomic properties showed that both strains 100T and C26T represent novel species, for which the names Chryseobacterium gallinarum sp. nov. (type strain 100T = LMG 27808T = CCM 8493T) and Chryseobacterium contaminans sp. nov. (type strain C26T = LMG 27810T = CCM 8492T) are proposed.

Chryseobacterium carnipullorum sp. nov., isolated from raw chicken

Three Gram-staining-negative, rod-shaped, non-spore-forming, non-motile, oxidase-positive, yellow pigmented and aerobic bacterial isolates designated 8_R23573, 9_R23581T and 10_R23577 were isolated from raw chicken at a broiler processing plant in Bloemfontein, South Africa. A polyphasic taxonomic approach was used to determine their exact taxonomic identities. Phylogenetic analysis of the 16S rRNA gene sequences showed that the three strains belonged to the genus Chryseobacterium , exhibiting the highest similarities to Chryseobacterium shigense DSM 17126T (98.6–99.2 %) and Chryseobacterium luteum DSM 18605T (98.3–98.7 %). The most abundant quinone was menaquinone MK-6 and the predominant cellular fatty acids were iso-15 : 0, iso-17 : 1ω9c, iso-17 : 0 3-OH and summed feature 3 (iso-16 : 1ω7c and/or iso-15 : 0 2-OH), which supported the affiliation of the strains to the genus Chryseobacterium . The DNA G+C contents of the strains were 36.9, 36.7 and 36.6 mol% respectively. The DNA–DNA hybridization results gave relatedness values ranging from 78.8 to 87.2 % among the three strains and 23.4 to 56.1 % to the two nearest phylogenetic neighbours C. shigense DSM 17126T and C. luteum LMG 23785T. On the basis of the data from this polyphasic study, the three strains are concluded to represent a novel species of the genus Chryseobacterium for which the name Chryseobacterium carnipullorum sp. nov. is proposed. The type strain is 9_R23581T ( = LMG 26732T = DSM 25581T).

Chryseobacterium angstadtii sp. nov., isolated from a newt tank

As part of an undergraduate microbiology course, a yellow-orange-pigmented, Gram-staining negative, rod-shaped, non-motile bacterial strain was isolated from a glass tank housing several red-spotted newts (Notophthalmus viridescens). The sequence of the 16S rRNA gene of this strain, designated KM(T), was 97.4-98.0 % similar to those of the type strains of Chryseobacterium luteum, C. shigense and C. vrystaatense, while the similarity levels for protein-coding genes were less than 94.7 % for rpoB, less than 92.1 % for groEL and less than 87.1 % for gyrB. These values are lower than for many other established distinct species. Polyphasic characterization and comparison to these relatives revealed that strain KM(T) was similar to other Chryseobacterium strains in that it contained MK-6 as its major respiratory quinone and phosphatidylethanolamine as the most abundant polar lipid, produced flexirubin-type pigments, oxidase and catalase and primarily contained the fatty acids iso-C15 : 0, iso-C17 : 1ω9c, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c). Based on the results of this study, strain KM(T) represents a novel species, for which the name Chryseobacterium angstadtii sp. nov. is proposed. The type strain is KM(T) ( = ATCC BAA-2160(T) = NRRL B-59516(T) = KCTC 23297(T)).

Chryseobacterium hispalense sp. nov., a plant-growth-promoting bacterium isolated from a rainwater pond in an olive plant nursery, and emended descriptions of Chryseobacterium defluvii, Chryseobacterium indologenes, Chryseobacterium wanjuense and Chryseobacterium gregarium

A novel non-motile, Gram-staining-negative, yellow-pigmented bacterium, designated AG13(T), isolated from a rain water pond at a plant nursery in Spain and characterized as a plant-growth-promoting bacterium, was investigated to determine its taxonomic status. The isolate grew best over a temperature range of 15-40 °C, at pH 5.0-8.0 and with 0-4 % (w/v) NaCl. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the genus Chryseobacterium. The DNA G+C content of the novel strain was 37.2 mol%. The strain had a polyamine pattern with sym-homospermidine as the major compound and produced flexirubin-type pigments. MK-6 was the dominant menaquinone and the major cellular fatty acids were iso-C15 : 0, C17 : 1ω9c and iso-C17 : 0 3-OH. The main polar lipids were phosphatidylethanolamine, aminolipids and several unidentified lipids. The 16S rRNA gene showed 92.0-97.2 % sequence similarity with those of the members of the genus Chryseobacterium. Based on chemotaxonomic and phenotypic traits, and DNA-DNA hybridizations with the type strains of the most closely related species, the isolate is proposed to represent a novel species, Chryseobacterium hispalense, type strain AG13(T) ( = DSM 25574(T) = CCUG 63019(T)). Emended descriptions of the species Chryseobacterium defluvii, Chryseobacterium indologenes, Chryseobacterium wanjuense and Chryseobacterium gregarium are also provided.

Chryseobacterium viscerum sp. nov., isolated from diseased fish

A taxonomic study was carried out on five Gram-staining-negative, catalase- and oxidase-positive, rod-shaped bacteria isolated from the gills and livers of five diseased rainbow trout. The five novel isolates were designated strains 687B-08T, 445-08, 452-08, 453B-08 and 967B-08. In phylogenetic analyses based on 16S rRNA gene sequences, the five novel strains appeared almost identical (99.0–100 % sequence similarity) and to belong to the genus Chryseobacterium . Strain 687B-08T (the strain selected to represent the five novel isolates) was found to be most closely related to Chryseobacterium oncorhynchi 701B-08T (98.9 % sequence similarity), Chryseobacterium ureilyticum F-Fue-04IIIaaaaT (98.6 %), Chryseobacterium indologenes ATCC 29897T (98.3 %), Chryseobacterium jejuense JS17-8T (98.1 %) and Chryseobacterium gleum ATCC 35910T (98.1 %). In DNA–DNA hybridizations, DNA–DNA relatedness values of 99–100 % were recorded between the five novel strains. Lower DNA–DNA relatedness values (21–57 %) were recorded between strain 687B-08T and C. oncorhynchi 701B-08T, C. ureilyticum F-Fue-04IIIaaaaT and the type strains of other closely related, established species of the genus Chryseobacterium . The predominant respiratory quinone of strain 687B-08T was MK-6 and the major cellular fatty acids were iso-C15 : 0, iso-C17 : 1ω9c, iso-C17 : 0 3-OH and C16 : 1ω6c. The G+C content of the genomic DNA of strain 687B-08T was 38.6 mol%. Based on the phenotypic and genotypic evidence, the five novel strains isolated from rainbow trout represent a single, novel species of the genus Chryseobacterium , for which the name Chryseobacterium viscerum sp. nov. is proposed. The type strain is 687B-08T ( = CECT 7793T  = CCUG 60103T).

Chryseobacterium piperi sp. nov., isolated from a freshwater creek

As part of an undergraduate microbiology course, a yellow–orange pigmented, Gram-staining negative, rod-shaped, non-motile bacterial strain, designated CTMT, was isolated from a creek in North-central Pennsylvania during the winter of 2006. The 16S rRNA gene sequence of the strain showed ~97 % similarity to that of Chryseobacterium soldanellicola PSD1-4T and Chryseobacterium soli JS6-6T, while the protein-coding gyrB gene sequence of strain CTMT showed <87 % similarity to those of its two closest relatives. Using a polyphasic approach, strain CTMT was characterized and compared to these and other closely related species of the genus Chryseobacterium. Strain CTMT was similar to other strains of the genus Chryseobacterium in that it contained MK-6 as its major respiratory quinone, produced flexirubin-type pigments, oxidase and catalase, hydrolysed DNA, gelatin and aesculin and contained the fatty acids iso-C15 : 0, iso-C17 : 1ω9c, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω6c, C16 : 1ω7c and/or iso-C15 : 0 2-OH). Based on the results of this study, strain CTMT represents a novel species of the genus Chryseobacterium, for which the name Chryseobacterium piperi sp. nov. is proposed. The type strain is CTMT ( = ATCC BAA-1782T  = CCUG 57707T  = JCM 15960T  = DSM 22249T  = KCTC 23267T).

Chryseobacterium treverense sp. nov., isolated from a human clinical source

A yellow-pigmented, Gram-reaction-negative bacterium isolated from a human clinical source was investigated using a polyphasic approach in order to clarify its taxonomic status. Comparative 16S rRNA gene sequence analysis showed that the new isolate constituted a distinct phyletic line within the genus Chryseobacterium, displaying >2.8 % sequence divergence with recognized species of this genus. The generic assignment was confirmed by chemotaxonomic data which revealed a fatty acid profile consisting of straight-chain saturated, monounsaturated and branched-chain fatty acids of iso-/anteiso-types as well as 3-hydroxylated fatty acids; a menaquinone with six isoprene units (MK-6) as the predominant respiratory quinone and sym-homospermidine as the predominant polyamine. The novel isolate could be distinguished from other members of the genus Chryseobacterium by a set of distinct biochemical properties. On the basis of phenotypic and phylogenetic evidence, it is proposed that the new isolate represents a novel species of the genus Chryseobacterium for which the name Chryseobacterium treverense sp. nov. is proposed. The type strain is IMMIB L-1519(T) (=DSM 22251(T)=CCUG 57657(T)).