Genome-Based Taxonomy of Brevundimonas with Reporting Brevundimonas huaxiensis sp. nov.

Brevundimonas is a genus of Gram-negative bacteria widely distributed in nature and is also an opportunistic pathogen causing health care-associated infections. Brevundimonas strain 090558T was recovered from a blood culture of a cancer patient and was subjected to genome sequencing and analysis. The average nucleotide identity and in silico DNA-DNA hybridization values between 090558T and type strains of Brevundimonas species were 78.76% to 93.94% and 19.8% to 53.9%, respectively, below the cutoff to define bacterial species. Detailed phenotypic tests were performed, suggesting that 090558T can be differentiated from other Brevundimonas species by its ability to assimilate sodium acetate but not to utilize glucose, trypsin, or ß-glucosidase. Strain 090558T (GDMCC 1.1871T or KCTC 82165T) therefore represents a novel Brevundimonas species, for which the name Brevundimonas huaxiensis sp. nov. is proposed. All Brevundimonas genomes available in GenBank (accessed on 25 January 2021) were retrieved, discarding those labeled "excluded from RefSeq" by GenBank, and included 82 genomes for precise species curation. In addition to the 21 Brevundimonas species with genomes of type strains available, we identified 29 Brevundimonas taxa that either belong to the 12 Brevundimonas species without available genomes of type strains or represent novel species. We found that more than half (57.3%) of the 82 Brevundimonas genomes need to be corrected for species assignation, including species mislabeling of a type strain. Our analysis highlights the complexity of Brevundimonas taxonomy. We also found that only some Brevundimonas species are associated with human infections, and more studies are warranted to understand their pathogenicity and epidemiology. IMPORTANCEBrevundimonas is a genus of the family Caulobacteraceae and comprises 33 species. Brevundimonas can cause various infections but remains poorly studied. In this study, we reported a novel Brevundimonas species, Brevundimonas huaxiensis, based on genome and phenotype studies of strain 090558T recovered from human blood. We then examined the species assignations of all Brevundimonas genomes (n = 82) in GenBank and found that in addition to the known Brevundimonas species with genome sequences of type strains available, there are 29 Brevundimonas taxa based on genome analysis, which need to be further studied using phenotype-based methods to establish their species status. Our study significantly updates the taxonomy of Brevundimonas and enhances our understanding of this genus of clinical relevance. The findings also encourage future studies on the characterization of novel Brevundimonas species.

Asticcacaulis tiandongensis sp. nov., a new member of the genus Asticcacaulis, isolated from a cave soil sample.

A Gram-stain negative, aerobic, motile and rod-shaped bacterium, designated strain 3.1105T, was isolated from a karst district soil sample collected from Tiandong cave, Guizhou province, south-west PR China. The isolate grew at 10-40 °C and pH 5.0-8.0 and tolerated up to 1 % NaCl (w/v) on R2A medium, with optimal growth at 25-30 °C, pH 7.0 and 0 % NaCl (w/v). Cells showed oxidase-positive and catalase-positive reactions. The respiratory quinone was Q-10. The predominant cellular fatty acids contained C18 : 1ω7c 11-methyl, summed feature 8 (C18 : 1ω7c or C18 : 1ω6c), C16 : 0 and C17 : 0. The major polar lipids were phosphatidylglycerol and monoglycosyldiglycerides. The genomic DNA G+C content was 56.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that 3.1105T should be affiliated to the genus Asticcacaulis and showed highest 16S rRNA gene sequence similarity values with Asticcacaulis excentricus CB 48T (96.0 %), Asticcacaulis endophyticus ZFGT-14T (95.3 %) and lower than 95.3 % similarity to other species of the genus Asticcacaulis. The polyphasic taxonomic characteristics indicated that strain 3.1105T represents a novel species of the genus Asticcacaulis, for which the name Asticcacaulis tiandongensis sp. nov., (type strain 3.1105T=KCTC 62978T=CCTCC AB 2018268T) is proposed.

Brevundimonas fluminis sp. nov., isolated from a river.

A Gram-stain-negative, rod-shaped, motile, facultatively aerobic and ivory-pigmented bacterium (designated strain LA-55T) was isolated from a river in the Republic of Korea. On the basis of 16S rRNA gene sequencing, strain LA-55T clustered with species of the genus Brevundimonas and was closely related to B revundimonas kwangchunensis KSL-102T (97.3 %), B revundimonas aurantiaca DSM 4731T (97.1 %), B revundimonas albigilva NHI-13T (97.0 %), B revundimonas balnearis FDRGB2bT (97.0 %) and Brevundimonas aveniformis DSM 17977T (97.0 %). The average nucleotide identity value between strain LA-55T and its closest-related strain was 74.1 %, indicating that strain LA-55T represents a novel species of the genus Brevundimonas. Growth occurred at 15-40 °C on Reasoner's 2A medium in the presence of 0-2 % NaCl (w/v) and at pH 6.0-8.0. The genomic DNA G+C content was 70.5 mol% and ubiquinone 10 (Q-10) was the major respiratory quinone. The major cellular fatty acids (>5 %) were C1 8 :1 ω6c and/or C1 8 :1 ω7c (summed feature 8), C16 : 0, C1 6 :1 ω6c and/or C1 6 :1 ω7c (summed feature 3) and C18 : 1 ω7c 11-methyl. The polar lipids consisted of phosphatidylglycerol, 1,2-di-O-acyl-3-O-[d-glucopyranosyl-(1→4)-α-d-glucopyranuronosyl]glycerol, 1,2-di-O-acyl-3-O-α-d-glucopyranuronosyl glycerol, unidentified aminolipid, unidentified phosphoglycolipid and unidentified lipids. Physiological and biochemical characteristics indicated that strain LA-55T represents a novel species of the genus Brevundimonas, for which the name Brevundimonas fluminis sp. nov. is proposed. The type strain is LA-55T (=KACC 19639T=LMG 30850T).

Brevundimonas lutea sp. nov., isolated from lake sediment.

A novel Gram-negative, aerobic, rod-shaped bacterium, designated NS26T, was isolated from a sediment sample collected from Taihu Lake in China. Colonies were orange, circular, smooth and neat-edged on Reasoner's 2A agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain NS26T belonged to the genus Brevundimonas and had the closest relationship with Brevundimonas halotolerans DSM 24448T (96.9 %). It grew at 20-37 °C (optimum, 28 °C), pH 5.5-10.5 (pH 7.0) and without NaCl. The major isoprenoid quinone was Q-10. The dominant cellular fatty acids were C18 : 1ω7c, C16 : 0 and C18 : 1ω7c 11-methyl. The polar lipid profile comprised 1,2-diacyl-3-O-(6-phosphatidyl-α-d-glucopyranosyl) glycerol, 1,2-di-O-acyl-3-O-α-d-glycopyranuronosyl glycerol, sulfoquinovosyl diacylglycerol, 1,2-di-O-acyl-3-O-[d-glycopyranosyl-(1→4)-α-d-glucopyranuronosyl] glycerol and phosphatidylglycerol. The G+C content of genomic DNA was 68.4 mol%. The average nucleotide identity value between strain NS26T and B.halotolerans DSM 24448T was 75.6 %. Based on the polyphasic taxonomic study, strain NS26T is suggested to be a novel species, for which the name Brevundimonas lutea sp. nov. is proposed. The type strain is NS26T (=CGMCC 1.13680T=NBRC 113554T).

Phenylobacterium soli sp. nov., isolated from arsenic and cadmium contaminated farmland soil.

A Gram-stain-negative, facultative anaerobic, non-motile and rod-shaped bacterial strain, designated LX32T, was isolated from arsenic and cadmium contaminated farmland soil. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain LX32T was closely related to Phenylobacterium hankyongense HKS-05T (97.7 % sequence similarity), Phenylobacterium kunshanense CCTCC AB 2013085T (97.4 %) and Phenylobacterium deserti CCTCC AB 2016297T (97.1 %). The average nucleotide identity values of the whole genome sequences of LX32T/P. hankyongense HKS-05T, LX32T/P. kunshanense CCTCC AB 2013085T and LX32T/P. deserti CCTCC AB 2016297T were 79.8, 77.9 and 77.5 %, respectively. Its genome size was 4.02 Mb, comprising 3998 predicted genes with a DNA G+C content of 70.1 mol%. The major fatty acids were C15 : 0, C16 : 0 and summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c). The polar lipid profiles consisted of phosphatidylglycerol, aminophospholipid, seven glycolipids and two unidentified polar lipids. The predominantly respiratory quinone was ubiquinone-10. Based on polyphasic analyses, the isolate is considered to represent a novel species of the genus Phenylobacterium, for which the name Phenylobacterium soli sp. nov. is proposed. The type strain is LX32T (=KCTC 62522=CCTCC AB 2018055).

Brevundimonas mongoliensis sp. nov., A Novel Psychrotolerant Bacterium Isolated from Oil-Contaminated Soil.

Two yellow-coloured, Gram-stain-negative, motile, and rod-shaped bacteria, designated strains R-10-10T and R-10-15 were isolated from oil-contaminated soil. Both strains were able to grow at 4-40 °C, pH 5.5-10.5, and 0-4% (w/v) NaCl concentration. These strains were taxonomically characterized by a polyphasic approach. Based on the 16S rRNA gene sequence analysis, both strains, R-10-10T and R-10-15, could be affiliated to the genus Brevundimonas and shared highest sequence similarity with Brevundimonas staleyi FWC43T (98.8%), Brevundimonas bullata TK0051T (98.6%), and Brevundimonas subvibrioides CB81T (98.3%). The pairwise sequence similarity between strains R-10-10T and R-10-15 was 99.9%. Both strains R-10-10T and R-10-15 contained phosphatidylglycerol, diphosphatidylglycerol, and four unidentified glycolipids as major polar lipids; ubiquinone-10 as sole respiratory quinone; and summed feature 8 (C18:1ω7c and/or C18:1ω6c), C16:0, summed feature 3 (C16:1ω7c and/or C16:1ω6c), and C18:1ω9c as major fatty acids. The genomic DNA G+C content values of strains R-10-10T and R-10-15 were 67.1 and 66.9 mol%, respectively. The DNA-DNA relatedness between R-10-10T and R-10-15 was higher than 70% but the values were less than 55% with closely related reference type strains. The morphological, physiological, chemotaxonomic, and phylogenetic data clearly distinguished strain R-10-10T from its closest phylogenetic neighbors. Thus, strain R-10-10T is considered to represent a novel species of the genus Brevundimonas, for which the name Brevundimonas mongoliensis sp. nov. is proposed. The type strain is R-10-10T (=KEMB 9005-696T = KACC 19387T = JCM 32172T), and strain R-10-15 is considered as an additional strain of the novel species.

Isolation and Characterization of PHA-Producing Bacteria from Propylene Oxide Saponification Wastewater Residual Sludge.

A polyhydroxyalkanoate (PHA)-producing strain was isolated from propylene oxide (PO) saponification wastewater activated sludge and was identified as Brevundimonas vesicularis UJN1 through 16S rDNA sequencing and Biolog microbiological identification. Single-factor and response surface methodology experiments were used to optimize the culture medium and conditions. The optimal C/N ratio was 100/1.04, and the optimal carbon and nitrogen sources were sucrose (10 g/L) and NH4Cl (0.104 g/L) respectively. The optimal culture conditions consisted of initial pH of 6.7 and an incubation temperature of 33.4 °C for 48 h, with 15% inoculum and 100 mL medium at an agitation rate of 180 rpm. The PHA concentration reached 34.1% of the cell dry weight and increased three times compared with that before optimization. The only report of PHA-producing bacteria by Brevundimonas vesicularis showed that the conversion rate of PHAs using glucose as the optimal carbon source was 1.67%. In our research, the conversion rate of PHAs with sucrose as the optimal carbon source was 3.05%, and PHA production using sucrose as the carbon source was much cheaper than that using glucose as the carbon source.

Brevundimonas humi sp. nov., an alphaproteobacterium isolated from forest soil.

During a study of bacterial diversity of soil, a novel strain, CA-15T, was isolated from Kyonggi University forest soil. Cells were aerobic, Gram-stain-negative, motile, non-spore-forming, rod-shaped, oxidase-positive and catalase- negative. Tyrosine was not oxidized but produced red pigmentation on an agar palte. Strain CA-15T hydrolysed Tween 60 and DNA. It grew at 15-35 °C (optimum, 25-30 °C), pH 6.0-10.0 (optimum, 7.0-9.0) and at 1.5 % (w/v) NaCl concentration. Phylogenetic analysis based on its 16S rRNA gene sequence indicated that strain CA-15T formed a lineage within the family Caulobacteraceae of the class Alphaproteobacteria that was distinct from various species of the genus Brevundimonas. Brevundimonas bullata DSM 7126T was the closest member of strain CA-15T on the basis of 16S rRNA gene sequence similarity (98.48 %). Q-10 was only an isoprenoid quinone detected for strain CA-15T. The major polar lipids were 1,2-di-O-acyl-3-O-[d-glucopyranosyl-(1→4)-αd-glucopyranuronosyl]glycerol, 1,2-di-O-acyl-3-O-[αd-glucopyranosyl]-sn-glycerol, 1,2-di-O-acyl-3-O-αd-glucopyranuronosylglycerol, 1,2-diacyl-3-O-[6'-phosphatidyl-αd-glucopyranosyl]glycerol and phosphatidylglycerol. The major cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0, C18 : 1ω7c 11-methyl and C17 : 1ω8c. The DNA G+C content of strain CA-15T was 63.6 mol%. The polyphasic characterization indicated that strain CA-15T represents a novel species in the genus Brevundimonas, for which the name Brevundimonas humi sp. nov. is proposed. The type strain of Brevundimonas humi is CA-15T (=KEMB 9005-528T=KACC 19106T=NBRC 112677T).

Phenylobacterium hankyongense sp. nov., isolated from ginseng field soil.

A Gram-stain-negative, aerobic, non-motile, non-spore-forming and rod-shaped bacterial strain, designated HKS-05T, was isolated from ginseng field soil. This bacterium was characterized to determine its taxonomic position by using the polyphasic approach. HKS-05T grew at 10-37 °C and at pH 6.0-8.0 on R2A agar. On the basis of 16S rRNA gene sequence similarity, HKS-05T was shown to represent a member of the family Caulobacteraceaeand to be related to Phenylobacterium lituiforme FaiI3T (98.1 % sequence similarity), 'Phenylobacterium zucineum' HLK1 (97.9 %), Phenylobacterium muchangponense A8T (97.7 %), Phenylobacteriumcomposti 4T-6T (97.2 %) and Phenylobacterium immobile ET (97.1 %). The major respiratory quinone was Q-10 and the major fatty acids were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0, and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c). The polar lipids were phosphatidylglycerol, unidentified glycolipids and unidentified polar lipids. The G+C content of the genomic DNA was 70.4 mol%. DNA-DNA relatedness values between HKS-05T and its closest phylogenetically neighbours were low. HKS-05T could be differentiated genotypically and phenotypically from the species of the genus Phenylobacterium with validly published names. The isolate therefore represents a novel species, for which the name Phenylobacteriumhankyongense sp. nov. is proposed, with the type strain HKS-05T (=KACC 18628T=LMG 30081T).

Phenylobacterium deserti sp. nov., isolated from desert soil.

A novel bacterial strain, designated YIM 73061T, was isolated from the Cholistan desert in Punjab, Pakistan, and characterized by using a polyphasic taxonomic approach. 16S rRNA gene sequence analysis revealed the highest levels of sequence similarity with respect to Phenylobacterium conjunctum FWC21T (97.6 %), Phenylobacterium lituiforme FaiI3T (97.4 %), Phenylobacteriumcomposti 4T-6T (97.0 %) and Phenylobacterium aquaticum W2-3-4T (96.8 %). Cells were Gram-stain-negative, aerobic and motile rods that formed orange colonies. The strain was oxidase- and catalase-positive. Growth occurred at 20-40 °C (optimum, 30-37 °C) at pH 5.0-8.0 (optimum, pH 7.0) and with 0-1 % (w/v) NaCl (optimum, 0-0.5 %). The major cellular fatty acids (>10 %) were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The polar lipid profile consisted of phosphatidylglycerol and four unidentified glycolipids. The major isoprenoid quinone was ubiquinone-10 (Q-10). The G+C content of the genomic DNA was 66.8 mol%. Strain YIM 73061T showed low levels of DNA-DNA relatedness to P. conjunctum FWC21T (27.2±2.6 %), P. lituiforme FaiI3T (24.6±1.1 %) and P.composti 4T-6T (18.4±3.1 %). On the basis of phylogenetic inference, chemotaxonomic characteristics and phenotypic data, strain YIM 73061T should be classified as representing a novel species, for which the name Phenylobacterium deserti sp. nov. is proposed. The type strain is YIM 73061T (=DSM 103871T=CCTCC AB 2016297T).

Experimental comparison of point-of-use filters for drinking water ultrafiltration.

BACKGROUND: Waterborne pathogens such as Pseudomonas spp. and Legionella spp. may persist in hospital water networks despite chemical disinfection. Point-of-use filtration represents a physical control measure that can be applied in high-risk areas to contain the exposure to such pathogens. New technologies have enabled an extension of filters' lifetimes and have made available faucet hollow-fibre filters for water ultrafiltration. AIM: To compare point-of-use filters applied to cold water within their period of validity. METHODS: Faucet hollow-fibre filters (filter A), shower hollow-fibre filters (filter B) and faucet membrane filters (filter C) were contaminated in two different sets of tests with standard bacterial strains (Pseudomonas aeruginosa DSM 939 and Brevundimonas diminuta ATCC 19146) and installed at points-of-use. Every day, from each faucet, 100 L of water was flushed. Before and after flushing, 250 mL of water was collected and analysed for microbiology. FINDINGS: There was a high capacity of microbial retention from filter C; filter B released only low Brevundimonas spp. counts; filter A showed poor retention of both micro-organisms. CONCLUSION: Hollow-fibre filters did not show good micro-organism retention. All point-of-use filters require an appropriate maintenance of structural parameters to ensure their efficiency.

Phenylobacterium aquaticum sp. nov., isolated from the reservoir of a water purifier.

A Gram-reaction-negative, strictly aerobic, non-motile, non-spore-forming, rod-shaped bacterial strain designated W2-3-4T was isolated from the reservoir of a water purifier. This bacterium was characterized to determine its taxonomic position by using a polyphasic approach. Strain W2-3-4T grew well at 25-30 °C on nutrient and R2A agars. On the basis of 16S rRNA gene sequence similarity, strain W2-3-4T was shown to belong to the family Caulobacteraceaeand to be related to Phenylobacterium conjunctumFWC21T (98.0 % sequence similarity) and Phenylobacterium haematophilum CCUG 26751T (97.2 %). Lower sequence similarities were found with the type strains of all other recognized members of the genus Phenylobacterium (95.7-97.1 %). The G+C content of the genomic DNA was 68.7 mol%. The major respiratory quinone was Q-10 and the major fatty acids were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0, C18 : 1ω7c 11-methyl and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c). The polar lipids were phosphatidylglycerol, an unknown phospholipid, four unknown glycolipids and three unidentified polar lipids. DNA-DNA relatedness values between strain W2-3-4Tand its closest phylogenetically neighbours were below 7 %. Strain W2-3-4T could be differentiated genotypically and phenotypically from recognized species of the genus Phenylobacterium. The isolate therefore represents a novel species, for which the name Phenylobacterium aquaticum sp. nov. is proposed, with the type strain W2-3-4T (=KACC 18306T=LMG 28593T).

Brevundimonas diminuta bacteremia in a man with myelodysplastic syndromes.

Brevundimonas diminuta are ubiquitous in the environment, but are infrequently isolated from clinical samples. Here we report a case of B. diminuta bacteremia in a man with myelodysplastic syndromes (MDS) at a teaching hospital in China and review the previously reported cases. The organism was confirmed by culture and 16s rRNA sequence analysis with highly sensitivity to broad-spectrum antibiotics. Our report and other cases demonstrated that the optimal therapeutic duration for B. diminuta infections in various situations remains to be established.

Biomineralization processes of calcite induced by bacteria isolated from marine sediments

Biomineralization is a known natural phenomenon associated with a wide range of bacterial species. Bacterial-induced calcium carbonate precipitation by marine isolates was investigated in this study. Three genera of ureolytic bacteria, Sporosarcina sp., Bacillus sp. and Brevundimonas sp. were observed to precipitate calcium carbonate minerals. Of these species, Sporosarcina sp. dominated the cultured isolates. B. lentus CP28 generated higher urease activity and facilitated more efficient precipitation of calcium carbonate at 3.24 ± 0.25 × 10−4 mg/cell. X-ray diffraction indicated that the dominant calcium carbonate phase was calcite. Scanning electron microscopy showed that morphologies of the minerals were dominated by cubic, rhombic and polygonal plate-like crystals. The dynamic process of microbial calcium carbonate precipitation revealed that B. lentus CP28 precipitated calcite crystals through the enzymatic hydrolysis of urea, and that when ammonium ion concentrations reached 746 mM and the pH reached 9.6, that favored calcite precipitation at a higher level of 96 mg/L. The results of this research provide evidence that a variety of marine bacteria can induce calcium carbonate precipitation, and may influence the marine carbonate cycle in natural environments.

Asticcacaulis endophyticus sp. nov., a prosthecate bacterium isolated from the root of Geum aleppicum.

A strictly aerobic, light-yellow-coloured, stalked bacterium, designated strain ZFGT-14(T), was isolated from the root of Geum aleppicum Jacq. collected from Taibai Mountain in Shaanxi province, north-west China, and was subjected to a taxonomic study using a polyphasic approach. This novel isolate grew at 7-33 °C (optimum 25-28 °C) and pH 6.0-10.0 (optimum pH 7.0-8.0). Flexirubin-type pigments were not produced. Cells were Gram-stain-negative, rod-shaped and motile with a single polar flagellum. The predominant respiratory quinone was Q-10. The major cellular fatty acids were summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c), C16 : 0, C19 : 0 cyclo ω8c and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and the major polar lipids were phosphatidylglycerol and glycolipids. The DNA G+C content was 57.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ZFGT-14(T) was most closely related to the genus Asticcacaulis and had low sequence similarity (95.0-95.9 %) with all species with validly published names within the genus Asticcacaulis. Based on the phenotypic, phylogenetic and genotypic data, strain ZFGT-14(T) is considered to represent a novel species of the genus Asticcacaulis, for which the name Asticcacaulis endophyticus sp. nov. is proposed. The type strain is ZFGT-14(T) ( = CCTCC AB 2013012(T) = KCTC 32296(T) = LMG 27605(T)).

Asticcacaulis solisilvae sp. nov., isolated from forest soil.

An obligately aerobic, chemoheterotrophic, mesophilic prosthecate bacterium, designated strain CGM1-3EN(T), was isolated from the enrichment cultures of forest soil from Cheonggyesan Mountain, Republic of Korea. Cells were Gram-reaction-negative, motile rods (1.3-2.4 µm long by 0.30-0.75 µm wide) with single flagella. The strain grew at 10-37 °C (optimum 25-30 °C) and at pH 4.5-9.5 (optimum 5.0-7.0). The major cellular fatty acids were C16 : 0, C18 : 1ω7c 11-methyl, C12 : 1 3-OH and summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c). The genomic DNA G+C content of strain CGM1-3EN(T) was 63.7 mol%. The closest phylogenetic neighbour to strain CGM1-3EN(T) was identified as Asticcacaulis biprosthecium DSM 4723(T) (97.2 % 16S rRNA gene sequence similarity) and the DNA-DNA hybridization value between strain CGM1-3EN(T) and A. biprosthecium DSM 4723(T) was less than 24.5 %. Strain CGM1-3EN(T) used d-glucose, d-fructose, sucrose, maltose, trehalose, d-mannose, d-mannitol, d-sorbitol, d-galactose, cellobiose, lactose, raffinose, fumarate, pyruvate, dl-alanine and glycerol as carbon sources. Based on data from the present polyphasic study, the forest soil isolate CGM1-3EN(T) is considered to represent a novel species of the genus Asticcacaulis, for which the name Asticcacaulis solisilvae sp. nov. is proposed. The type strain is CGM1-3EN(T) ( = AIM0088(T) = KCTC 32102(T) = JCM 18544(T)).

Brevundimonas abyssalis sp. nov., a dimorphic prosthecate bacterium isolated from deep-subsea floor sediment.

A novel Gram-negative, aerobic, psychrotolerant, alkali-tolerant, heterotrophic and dimorphic prosthecate bacterium, designated strain TAR-001(T), was isolated from deep-sea floor sediment in Japan. Cells of this strain had a dimorphic life cycle and developed an adhesive stalk at a site not coincident with the centre of the cell pole, and the other type of cell, a swarm cell, had a polar flagellum. Colonies were glossy, viscous and yellowish-white in colour. The temperature, pH and salt concentration range for growth were 2-41 °C, pH 6.5-10.0 and 1-4% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that strain TAR-001(T) belongs to the family Caulobacteraceae of the class Alphaproteobacteria, and lies between the genus Brevundimonas and the genus Caulobacter. Levels of similarity between the 16S rRNA gene sequence of strain TAR-001(T) and those of the type strains of Brevundimonas species were 93.3-95.7%; highest sequence similarity was with the type strain of Brevundimonas diminuta. Levels of sequence similarity between those of the type strains of Caulobacter species were 94.9-96.0%; highest sequence similarity was with the type strain of Caulobacter mirabilis. The G+C content of strain TAR-001(T) was 67.6 mol%. Q-10 was the major respiratory isoprenoid quinone. The major fatty acids were C18:1ω7c and C16:0, and the presence of 1,2-di-O-acyl-3-O-[D-glucopyranosyl-(1→4)-α-D-glucopyranuronosyl]glycerol suggests strain TAR-001(T) is more closely to the genus Brevundimonas than to the genus Caulobacter. The mean DNA-DNA hybridization levels between strain TAR-001(T) and the type strains of two species of the genus Brevundimonas were higher than that of the genus Caulobacter. On the basis of polyphasic biological features and the 16S rRNA gene sequence comparison presented here, strain TAR-001(T) is considered to represent a novel species of the genus Brevundimonas, for which the name Brevundimonas abyssalis sp. nov. is proposed; the type strain is TAR-001(T) (=JCM 18150(T)=CECT 8073(T)).

Phenylobacterium muchangponense sp. nov., isolated from beach soil, and emended description of the genus Phenylobacterium.

A Gram-staining-negative, non-motile, aerobic bacterium, designated strain A8T, was isolated from the beach soil of Muchangpo, Korea. Cells were rod-shaped (0.5-0.6×0.7-1.3 µm) and colonies were colourless, circular with entire edges and had a glistening surface. The isolate grew optimally at 25-35 °C and did not require NaCl for growth. Strain A8T could not assimilate acetate, DL-lactate, succinate, antipyrine or chloridazon, but weakly assimilated L-phenylalanine. Major fatty acids were summed feature 7 (comprising C18:1ω7c/ω9t/ω12t), C16:0 and summed feature 4 (comprising C16:1ω7c/ iso-C15:0 2-OH). The major isoprenoid quinone was ubiquinone-10 and the DNA G+C content was 72.3 mol%. Comparative 16S rRNA gene sequence studies showed that strain A8T belonged to the family Caulobacteraceae, class Alphaproteobacteria and was most closely related to type strains of members of the genus Phenylobacterium (95.7-97.1 % similarity). Signature nucleotides and phylogenetic analysis of the 16S rRNA gene sequence also suggested that strain A8T was affiliated with the genus Phenylobacterium. Low DNA-DNA relatedness values (3.0±1.8-11.5±3.2 %) indicated that strain A8T represented a distinct species that was separated from other type strains in the genus Phenylobacterium. On the basis of evidence from a polyphasic study, it is proposed that strain A8T (=KACC 15042T=LMG 25973T) represents the type strain of a novel species, Phenylobacterium muchangponense sp. nov. An emended description of the genus Phenylobacterium is also presented.

Brevundimonas viscosa sp. nov., isolated from saline soil.

A Gram-negative, rod-shaped bacterial strain, designated F3(T), was isolated from a saline soil sample in China and studied by using a polyphasic taxonomic approach. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain F3(T) was affiliated with the genus Brevundimonas, with Brevundimonas kwangchunensis KSL-102(T) (98.4 % similarity) and Brevundimonas alba DSM 4736(T) (98.2 %) as its closest relatives. Strain F3(T) contained ubiquinone-10 (Q-10) as the predominant ubiquinone and C(18 : 1)ω7c, C(17 : 1)ω8c and C(16 : 0) as the major fatty acids. The DNA G+C content of strain F3(T) was 66.7 mol%. Levels of DNA-DNA relatedness between strain F3(T) and the type strains of closely related Brevundimonas species were below 22 %. On the basis of phenotypic characteristics and genotypic distinctiveness, strain F3(T) should be classified as representing a novel species of the genus Brevundimonas, for which the name Brevundimonas viscosa sp. nov. is proposed. The type strain is F3(T) ( = CGMCC 1.10683(T) = JCM 17426(T)).

Bacteremia caused by Brevundimonas species at a tertiary care hospital in Taiwan, 2000-2010.

We investigated clinical and microbiological characteristics of 30 patients with Brevundimonas bacteremia treated at a tertiary care hospital in Taiwan during 2000-2010. All the 30 bacteria isolates were confirmed to the species level by 16S rRNA sequencing analysis. Minimum inhibitory concentrations (MICs) of 11 antimicrobial agents against these isolates were determined by the agar dilution method. Seventeen (57%) patients had underlying malignancy, 12 (40%) had undergone central catheter placement, and 13 (43%) had received chemotherapy within the previous three months. Eight (27%) patients had community-acquired bacteremia and the remaining 22 patients (73%) had healthcare-associated bacteremia. The overall 14-day and 30-day mortality rates were 13% and 17%, respectively. Among the 30 isolates, B. vesicularis constituted most commonly (n = 22, 63%), followed by B. nasdae (n = 5) and B. diminuta (n = 3). All isolates were susceptible to piperacillin-tazobactam and amikacin, while all were resistant to ciprofloxacin and colistin. Tigecycline (MICs at which 90% of isolates are inhibited [MIC(90)] was 0.12 mg/L) and doripenem (MIC(90) of 1 mg/L) both possessed good in vitro activities. In conclusions, Brevundimonas should be considered a pathogen that can cause bacteremia in immunocompromised hosts. Piperacillin-tazobactam, amikacin, doripenem, and tigecycline exhibit good in vitro activities against these ciprofloxacin- and colistin-resistant Brevundimonas species.