Influence of obesity on subgingival microbiota composition in subjects with different periodontal status: a systematic review.

Objective: This systematic review aimed to investigate the changes in the composition of the subgingival microbiota among subjects with normo-weight, overweight and obesity, in conditions of periodontal health and disease. Materials and Methods: The protocol for this study was designed following PRISMA guidelines. Records were identified using different search engines (PubMed/MedLine, Scopus and Web of Science). Observational studies, in human subjects diagnosed with obesity (BMI >30kg/m2) and periodontal disease (gingivitis and periodontitis), on the analysis of subgingival microbiota were selected. Eight articles were included. Results: The subgingival microbiota of 1,229 subjects (n=894 exposure group and n=335 control group) was analyzed. Periodontal pathogens were the most common bacteria detected in subjects with obesity and periodontitis (Porphyromonas gingivalis, Tannerella forsythia, Campylobacter gracilis, Eubacterium nodatum, Fusobacterium nucleatum spp. vincentii, Parvimonas micra, Prevotella intermedia, Campylobacter rectus, and Aggregatibacter actinomycetemcomitans), as along with some accessory pathogens such as: Streptococcus gordonii, and Veillonella parvula that favor the virulence of late colonizers. Conclusions: Although there are evident alterations in the composition of the subgingival microbiota in subjects with obesity and periodontitis, it is still a challenge to identify a specific pattern of microbiota in these subjects. If associations between subgingival plaque microorganisms and obesity are confirmed, microbiome analysis could be a useful tool to improve preventive measures and the management of people with obesity.

Objetivo: Esta revisión sistemática tuvo como objetivo investigar los cambios en la composición de la microbiota subgingival entre sujetos con normopeso, sobrepeso y obesidad, en condiciones de salud y enfermedad periodontal. Materiales y métodos: El protocolo de este estudio se diseñó siguiendo las directrices PRISMA. Los registros se identificaron utilizando diferentes motores de búsqueda (PubMed/MedLine, Scopus y Web of Science). Se seleccionaron estudios observacionales en sujetos humanos diagnosticados con obesidad (IMC >30kg/m2) y enfermedad periodontal (gingivitis y periodontitis), sobre el análisis de la microbiota subgingival. Se incluyeron ocho artículos. Resultados: Se analizó la microbiota subgingival de 1229 sujetos (n = 894 grupo de exposición y n = 335 grupo de control). Los patógenos periodontales fueron las bacterias más comunes detectadas en los sujetos con obesidad y periodontitis (Porphyromonas gingivalis, Tannerella forsythia, Campylobacter gracilis, Eubacterium nodatum, Fusobacterium nucleatum spp. vincentii, Parvimonas micra, Prevotella intermedia, Campylobacter rectus y Aggregatibacter actinomycetemcomitans), junto con algunos patógenos accesorios, como Streptococcus gordonii y Veillonella parvula, que favorecen la virulencia de los colonizadores tardíos. Conclusiones: Aunque existen alteraciones evidentes en la composición de la microbiota subgingival en sujetos con obesidad y periodontitis, sigue siendo un reto identificar un patrón específico de microbiota en ellos. Si se confirman las asociaciones entre los microorganismos de la placa subgingival y la obesidad, el análisis del microbioma podría ser una herramienta útil para mejorar las medidas preventivas y el manejo de las personas con obesidad.

Subgingival microbial profiles in pre- and postmenopausal women: Associations with serum estradiol levels.

BACKGROUND: Subgingival dental plaque is an ecosystem playing a key role in supporting both oral health and systemic health. Menopause-related changes have the potential to disrupt its balance, which is crucial to postmenopausal well-being. Our study explored how circulating estradiol levels correlate with subgingival microbial composition using checkerboard DNA-DNA hybridization in premenopausal and postmenopausal women. We also demonstrated that combining this method with 16S ribosomal RNA (rRNA) sequencing insights remains valuable for examining subgingival ecology. METHODS: We assessed 40 bacterial species in 77 premenopausal and 81 postmenopausal women using checkerboard DNA-DNA hybridization and measured serum estradiol with enzyme-linked immunosorbent assay (ELISA). Women were categorized by subgingival dysbiosis severity using a modified Subgingival Microbial Dysbiosis Index (mSMDI). Six women from each normobiotic and dysbiotic subgroup across premenopausal and postmenopausal women underwent 16S rRNA sequencing analysis. RESULTS: DNA checkerboard analysis revealed that most observed variability in individual bacterial proportions is associated with periodontitis. Two species, Leptotrichia buccalis and Streptococcus constellatus, exhibited differences related to estradiol levels within the premenopausal group (p = 0.055 and p = 0.009, respectively). 16S rRNA sequencing confirmed the mSMDI's validity in categorizing normobiotic and dysbiotic states. Menopausal status was not associated with a dysbiotic shift in the subgingival microbiome despite significantly more attachment loss in postmenopausal compared to premenopausal women. CONCLUSIONS: Our results indicate that decreased estradiol levels or increased attachment loss during menopause are not associated with changes in species abundance or dysbiotic shifts in women. The mSMDI may be a useful tool for classifying subgingival ecology based on its normobiotic or dysbiotic inclination.

Identification and characterization of a novel α-haemolytic streptococci, Streptococcus parapneumoniae sp. nov., which caused bacteremia with pyelonephritis.

OBJECTIVES: We report a case of bacteremia with pyelonephritis in an adult male with an underlying disease caused by α-hemolytic streptococci. α-Hemolytic streptococci were isolated from blood, but it was challenging to identify its species. This study aimed to characterize the causative bacterium SP4011 and to elucidate its species. METHODS: The whole-genome sequence and biochemical characteristics of SP4011 were determined. Based on the genome sequence, phylogenetic analysis was performed with standard strains of each species of α-hemolytic streptococci. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values were calculated. RESULTS: SP4011 showed optochin susceptibility and bile solubility, but did not react with pneumococcal omni antiserum. Phylogenetic analysis of the whole-genome sequence showed that SP4011 clustered with S. pneumoniae and S. pseodopneumoniae and was most closely related to S. pseodopneumoniae. Genomic analysis revealed that ANI and dDDH values between SP4011 and S. pseodopneumoniae were 94.0 % and 56.0 %, respectively, and between SP4011 and S. pneumoniae were 93.3 % and 52.2 %, respectively. Biochemical characteristics also showed differences between SP4011 and S. pseodopneumoniae and between SP4011 and S. pneumoniae. These results indicate that SP4011 is a novel species. CONCLUSION: Our findings indicate that SP4011 is a novel species of the genus Streptococcus. SP4011 has biochemical characteristics similar to S. pneumoniae, making it challenging to differentiate and requiring careful clinical diagnosis. This isolate was proposed to be a novel species, Streptococcus parapneumoniae sp. nov. The strain type is SP4011T (= JCM 36068T = KCTC 21228T).

Genome sequence-based species classification of Enterobacter cloacae complex: a study among clinical isolates.

Accurate species-level identification of Enterobacter cloacae complex (ECC) is crucial for related research. The classification of ECC is based on strain-to-strain phylogenetic congruence, as well as genomic features including average nucleotide identity (ANI) and digitalized DNA-DNA hybridization (dDDH). ANI and dDDH derived from whole-genome sequencing have emerged as a reliable metric for assessing genetic relatedness between genomes and are increasingly recognized as a standard for species delimitation. Up to now, there are two different classification methods for ECC. The first one categorizes E. hormaechei, a species within ECC, into five subspecies (E. hormaechei subsp. steigerwaltii, subsp. oharae, subsp. xiangfangensis, subsp. hoffmannii, and subsp. hormaechei). The second classifies E. hormaechei as three species: E. hormaechei, "E. xiangfangensis," "E. hoffmanii." While the former is well-accepted in the academic area, the latter may have a greater ability to distinguish different species of ECC. To assess the suitability of these identification criteria for clinical ECC isolates, we conducted a comprehensive analysis involving phylogenetic analysis, ANI and dDDH value alignment, virulence gene identification, and capsule typing on 256 clinical ECC strains isolated from the bloodstream. Our findings indicated that the method of categorizing E. hormaechei into five subspecies has better correlation and consistency with the molecular characteristics of clinical ECC isolates, as evidenced by phylogenetic analysis, virulence genes, and capsule typing. Therefore, the subspecies-based classification method appears more suitable for taxonomic assignments of clinical ECC isolates. IMPORTANCE: Standardizing taxonomy of the Enterobacter cloacae complex (ECC) is necessary for data integration across diverse studies. The study utilized whole-genome data to accurately identify 256 clinical ECC isolated from bloodstream infections using average nucleotide identity (ANI), digitalized DNA-DNA hybridization (dDDH), and phylogenetic analysis. Through comprehensive assessments including phylogenetic analysis, ANI and dDDH comparisons, virulence gene, and capsule typing of the 256 clinical isolates, it was concluded that the classification method based on subspecies exhibited better correlation and consistency with the molecular characteristics of clinical ECC isolates. In summary, this research contributes to the precise identification of clinical ECC at the species level and expands our understanding of ECC.

TaqMan Real-Time PCR Assay for Specific Detection and Differentiation of Xanthomonas translucens pv. undulosa from Other Pathovars Targeting a Recombination Mediator Gene, recF.

Bacterial leaf streak and black chaff diseases of wheat caused by Xanthomonas translucens pv. undulosa is becoming a major constraint to growers and trade since it is seedborne. Molecular tools for specific detection/differentiation of pv. undulosa are lacking. We report the development of a TaqMan real-time PCR for specific detection/identification of pv. undulosa targeting the recombination mediator gene (recF). Analysis of the complete recF (1,117 bp) sequences identified the gene as a reliable phylogenetic marker for identification of pv. undulosa, differentiating it from the other pathovars; recF-based sequence homology values among the 11 pathovars correlated well with genome-based DNA-DNA hybridization values. The discriminatory power of recF to differentiate pv. undulosa from the other pathovars is due to nucleotide polymorphic positions. We used these nucleotide polymorphisms to develop a TaqMan PCR for specific detection of pv. undulosa. The specificity of the assay was validated using 67 bacterial and fungal/oomycete strains. The selected primers and the double-quenched FAM-labeled TaqMan probe were specific for the detection of 11 pv. undulosa/secalis strains. The 56 strains of other X. translucens pathovars (n = 39) and non-Xanthomonas spp. (n = 17) did not exhibit any detectable fluorescence. Also, greenhouse-inoculated and naturally infected wheat leaf samples showed positive reactions for the presence of pv. undulosa DNA but not healthy control plants. The TaqMan assay reliably detected as low as 1-pg DNA amount and 10 colony forming units of the target pathogen per reaction. This TaqMan assay could be useful to regulatory agencies with economic benefits to wheat growers.

Stenotrophomonas riyadhensis sp. nov., isolated from a hospital floor swab.

During the analysis of a collection of Pseudomonas strains linked to an outbreak in an intensive care unit at King Faisal Specialist Hospital and Research Center in 2019, one isolate (CFS3442T) was identified phenotypically as Pseudomonas aeruginosa. However, whole-genome sequencing revealed its true identity as a member of the genus Stenotrophomonas, distinct from both P. aeruginosa and Stenotrophomonas maltophilia. The isolate demonstrated: (i) a significant phylogenetic distance from P. aeruginosa; (ii) considerable genomic differences from several S. maltophilia reference strains and other Stenotrophomonas species; and (iii) unique phenotypic characteristics. Based on the combined geno- and phenotypic data, we propose that this isolate represents a novel species within the genus Stenotrophomonas, for which the name Stenotrophomonas riyadhensis sp. nov. is proposed. The type strain is CFS3442T (=NCTC 14921T=LMG 33162T).

Assessment of Subgingival Biofilm and its Relationship with the Status of Tumors in a Population with Breast Cancer

This study aimed to compare the subgingival microbiota of subjects with and without breast cancer (BC). Patients with BC (Group 1; n= 50) and without BC (Group 2; n=50) with periodontitis (A) and without periodontitis (B). The study was conducted in two phases (P1 and P2). One biofilm sample was collected from each subject and analyzed by DNA-DNA Hybridization (Checkerboard DNA-DNA). The relative abundance of the subgingival microbiota differed between the Case and Control groups. However, some species were higher in patients in the Case than in Control subjects and differed between the groups in both phases. Composition of the subgingival microbial community according to the Socransky complex was related to periodontal disease, followed by clinical attachment of level (CAL ≥4mm), age, and tooth loss, which were found to be abundant in Cases when compared with controls. Patients with Tumor Grade II and III had a higher prevalence of tooth loss and CAL≥4mm. It was concluded that in individuals with BC, the sub-gingival microbiota exhibited atypical changes, but they developed periodontal disease.

El objetivo de este estudio fue comparar la microbiota subgingival de sujetos con y sin cáncer de mama (CM). Pacientes con CM (Grupo 1; n= 50) y sin CM (Grupo 2; n=50) con periodontitis (A) y sin periodontitis (B). El estudio se realizó en das fases (P1 y P2). Se recogió una muestra de biopelícula de cada sujeto y se analizó mediante hibridación ADN-ADN (tablero de ajedrez ADN-ADN). La abundancia relativa de la microbiota subgingival difirió entre los grupos de Caso y Control. Sin embargo, algunas especies fueron más altas en los pacientes del Caso que en los sujetos del Control y difirieron entre los grupos en ambas fases. La composición de la comunidad microbiana subgingival según el complejo de Socransky se relacionó con la enfermedad periodontal, seguida por el nivel de inserción clínica (CAL≥4mm), la edad y la pérdida de dientes, que se mostró abundante en los casos en comparación con los controles. Los pacientes con Tumor Grado II y III tuvieron mayor prevalencia de pérdida dental y CAL≥4mm. Se concluyó que en individuos con CM la microbiota subgingival presentó cambios atípicos, pero sin embargo, desarrollaron enfermedad periodontal.

Isolation and characterization of Pinibacter soli sp. nov., and in silico genome mining of Pinibacter for biosynthetic gene cluster prediction.

A Gram-stain-negative, aerobic, rod-shaped, non-motile and non-flagellated novel bacterial strain, designated MAH-24T, was isolated from the rhizospheric soil of a pine garden. The colonies were observed to be orange-coloured, smooth, spherical and 0.4-0.8 mm in diameter when grown on Reasoner's 2A agar medium for 2 days. Strain MAH-24T was found to be able to grow at 10-35 °C, at pH 6.0-9.0 and in the presence of 0-1.0 % NaCl (w/v). The strain was found to be positive for the catalase and oxidase tests. The strain was positive for hydrolysis of aesculin and l-tyrosine. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Pinibacter and to be closely related to Pinibacter aurantiacus MAH-26T (99.2 % sequence similarity). The novel strain MAH-24T has a draft genome size of 5 918 133 bp (13 contigs), annotated with 4613 protein-coding genes, 47 tRNA and three rRNA genes. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MAH-24T and the closest type strain P. aurantiacus MAH-26T were in the range of 85.3 and 29.9 %, respectively. In silico genome mining revealed that both novel strain MAH-24T and P. aurantiacus MAH-26T have a significant potential for the production of novel natural products in the future. The genomic DNA G+C content was determined to be 41.0 mol%. The predominant isoprenoid quinone was menaquinone-7. The major fatty acids were identified as C15:0 iso, C15:1 iso G and C17:0 iso 3OH. On the basis of dDDH, ANI, genotypic, chemotaxonomic and physiological data, strain MAH-24T represents a novel species within the genus Pinibacter, for which the name Pinibacter soli sp. nov. is proposed, with MAH-24T (=KACC 19747T=CGMCC 1.13659T) as the type strain.

Vibrio chanodichtyis sp. nov., isolated from the intestine of swordfish Chanodichthys dabryi.

A Gram-stain-negative, facultatively anaerobic, motile, curved-rod-shaped flagellated bacterium, designated DSL-7T, was isolated from the intestine of Chanodichthys dabryi in the Yangtze river, PR China. The strain grew optimally in tryptone soy broth medium at 37 °C, pH 7.0 and with 1 % (w/v) NaCl. Strain DSL-7T showed less than 96.2 % 16S rRNA gene sequence similarity to type strains of the genus Vibrio. Phylogenetic analysis based on genomes indicated that strain DSL-7T belonged to the genus Vibrio and formed a subclade with Vibrio mimicus NCTC 11435T, Vibrio metoecus OP3HT, Vibrio cholerae ATCC 14035T, Vibrio albensis ATCC14547T, Vibrio paracholerae OP3HEDC-792T and Vibrio tarriae 2521-89T. The average nucleotide identity (ANI) and in digital DNA-DNA hybridization (dDDH) values between DSL-7T and closely related type strains were below the accepted threshold to delineate a new species of 95 and 70 %, respectively. The major cellular fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0, summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C14 : 0. The genomic DNA G+C content was 47.6 mol%. Based on the phenotypic, chemotaxonomic, phylogenetic and genomic data, strain DSL-7T represents a novel species of the genus Vibrio, for which the name Vibrio chanodichtyis sp. nov. is proposed, with strain DSL-7T (=KCTC 92851T=CCTCC AB 2022396T) as the type strain.

Plant-Associated Representatives of the Bacillus cereus Group Are a Rich Source of Antimicrobial Compounds.

Seventeen bacterial strains able to suppress plant pathogens have been isolated from healthy Vietnamese crop plants and taxonomically assigned as members of the Bacillus cereus group. In order to prove their potential as biocontrol agents, we perform a comprehensive analysis that included the whole-genome sequencing of selected strains and the mining for genes and gene clusters involved in the synthesis of endo- and exotoxins and secondary metabolites, such as antimicrobial peptides (AMPs). Kurstakin, thumolycin, and other AMPs were detected and characterized by different mass spectrometric methods, such as MALDI-TOF-MS and LIFT-MALDI-TOF/TOF fragment analysis. Based on their whole-genome sequences, the plant-associated isolates were assigned to the following species and subspecies: B. cereus subsp. cereus (6), B. cereus subsp. bombysepticus (5), Bacillus tropicus (2), and Bacillus pacificus. These three isolates represent novel genomospecies. Genes encoding entomopathogenic crystal and vegetative proteins were detected in B. cereus subsp. bombysepticus TK1. The in vitro assays revealed that many plant-associated isolates enhanced plant growth and suppressed plant pathogens. Our findings indicate that the plant-associated representatives of the B. cereus group are a rich source of putative antimicrobial compounds with potential in sustainable agriculture. However, the presence of virulence genes might restrict their application as biologicals in agriculture.

Assigning new supergroups V and W to the Wolbachia diversity.

Wolbachia are endosymbiotic and alphaproteobacteria that belong to the order Rickettsiales. They are known to infect half of the insect population and cause host manipulation, and have been categorized into 19 monophyletic lineages called supergroups. Recently, two strains, wCfeJ and wCfeT were isolated from cat fleas (Ctenocephalides felis), but their supergroup relationships were not assigned. In this article, we have attempted to classify these two novel strains and establish their evolutionary lineage (i.e., supergroup designation). For this we performed 16S rRNA similarity analysis and reconstructed 16S rRNA phylogeny of 52 Wolbachia strains (including two novel strains) belong to 19 supergroups. We also performed average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) studies to measure genomic similarity between the two novel genomes. The results revealed that 16S rRNA similarity between the two novel strains is 97.94%, which is below the threshold value of 98.6% and phylogeny shows that they are placed at the two different positions (i.e., showing distinct evolutionary lineages). Further, genomic similarity analysis revealed that the novel genomes have ANI and dDDH values 79% and 22.4% respectively, which were below the threshold value of ANI (95%) and dDDH (70%). These results suggested that the novel strains neither shared a species boundary between them nor with any other previously identified supergroups, which designate them as two new supergroups, namely supergroup V (strain wCfeJ) and supergroup W (strain wCfeT).

Sphingobium agri sp. nov., isolated from rhizospheric soil of eggplant.

A Gram-stain-negative, aerobic, short rod-shaped and motile bacterial strain, designated MAH-33T, was isolated from rhizospheric soil of eggplant. The colonies were observed to be yellow-coloured, smooth, spherical and 0.1-0.3 mm in diameter when grown on TSA agar medium for 2 days. Strain MAH-33T was found to be able to grow at 10-40 °C, at pH 5.0-10.0 and at 0-3.0 % NaCl (w/v). The strain was found to be positive for both oxidase and catalase tests. The strain was positive for hydrolysis of tyrosine and aesculin. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Sphingobium and to be closely related to Sphingobium quisquiliarum P25T (98.4 % similarity), Sphingobium mellinum WI4T (97.8 %), Sphingobium fuliginis TKPT (97.3 %) and Sphingobium herbicidovorans NBRC 16415T (96.9 %). The novel strain MAH-33T has a draft genome size of 3 908 768 bp (28 contigs), annotated with 3689 protein-coding genes, 45 tRNA and three rRNA genes. The average nucleotide identity and digital DNA-DNA hybridization values between strain MAH-33T and closely related type strains were in the range of 79.8-81.6 % and 23.2-24.5 %, respectively. The genomic DNA G+C content was determined to be 62.2 %. The predominant isoprenoid quinone was ubiquinone 10. The major fatty acids were identified as C16 : 0 and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The polar lipids identified in strain MAH-33T were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, sphingoglycolipid, phosphatidylcholine; one unknown phospholipid and one unknown lipid. On the basis of digital DNA-DNA hybridization, ANI value, genotypic analysis, chemotaxonomic and physiological data, strain MAH-33T represents a novel species within the genus Sphingobium, for which the name Sphingobium agri sp. nov. is proposed, with MAH-33T (=KACC 19973T = CGMCC 1.16609T) as the type strain.

Description of Flavobacterium agricola sp. nov., an auxin producing bacterium isolated from paddy field.

An auxin-producing bacterial strain, CC-SYL302T, was isolated from paddy soil in Taiwan and identified using a polyphasic taxonomic approach. The cells were observed to be aerobic, non-motile, non-spore-forming rods, and tested positive for catalase and oxidase. Produced carotenoid but flexirubin-type pigments were absent. Optimal growth of strain CC-SYL302T was observed at 25 °C, pH 7.0, and with 2% (w/v) NaCl present. Based on analysis of 16S rRNA gene sequences, it was determined that strain CC-SYL302T belongs to the genus Flavobacterium of the Flavobacteriaceae family. The closest known relatives of this strain are F. tangerinum YIM 102701-2 T (with 93.3% similarity) and F. cucumis R2A45-3 T (with 93.1% similarity). Digital DNA-DNA hybridization (dDDH) values were calculated to assess the genetic distance between strain CC-SYL302T and its closest relatives, with mean values of 21.3% for F. tangerinum and 20.4% for F. cucumis. Strain CC-SYL302T exhibited the highest orthologous average nucleotide identity (OrthoANI) values with members of the Flavobacterium genus, ranging from 67.2 to 72.1% (n = 22). The dominating cellular fatty acids (> 5%) included iso-C14:0, iso-C15:0, iso-C16:0, iso-C15:0 3-OH, iso-C17:0 3-OH, C16:1 ω6c/C16:1 ω7c and C16:0 10-methyl/iso-C17:1 ω9c. The polar lipid profile consisted of phosphatidylethanolamine, an unidentified aminolipid, an unidentified aminophospholipid, and nine unidentified polar lipids. The genome (2.7 Mb) contained 33.6% GC content, and the major polyamines were putrescine and sym-homospermidine. Strain CC-SYL302T exhibits distinct phylogenetic, phenotypic, and chemotaxonomic characteristics, as well as unique results in comparative analysis of 16S rRNA gene sequence, OrthoANI, dDDH, and phylogenomic placement. Therefore, it is proposed that this strain represents a new species of the Flavobacterium genus, for which the name Flavobacterium agricola sp. nov. is proposed. The type strain is CC-SYL302T (= BCRC 81320 T = JCM 34764 T).

Sphingomonas oryzagri sp. nov., isolated from a rice field.

A Gram-stain-negative, aerobic, short rod-shaped and motile novel bacterial strain, designated MAHUQ-71T, was isolated from the soil of a rice field. The colonies were observed to be milky yellow-coloured, smooth, spherical and 0.1-0.4 mm in diameter when grown on Reasoner's 2A agar medium for 2 days. Strain MAHUQ-71T was found to be able to grow at 15-37 °C, pH 5.0-10.0 and with 0-3.0 % NaCl (w/v). The strain was found to be positive for the catalase test, but negative for the oxidase test. The strain was positive for hydrolysis of aesculin and Tween 20. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Sphingomonas and to be closely related to Sphingomonas chungangi MAH-6T (98.5 % sequence similarity), Sphingomonas polyaromaticivorans B2-7T (98.4 %) and Sphingomonas oligoaromativorans SY-6T (96.6 %). Strain MAHUQ-71T has a draft genome size of 4 255 278 bp (10 contigs), annotated with 4098 protein-coding genes, 47 tRNA and three rRNA genes. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MAHUQ-71T and the closest type strain S. chungangi MAH-6T were in the range of 85.6 and 30.6 %, respectively. The genomic DNA G+C content was determined to be 66.7 mol%. The predominant isoprenoid quinone was ubiquinone 10. The major fatty acids were identified as summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C16 : 0 and C14 : 0 2OH. The main polar lipids were phosphatidylcholine, phosphatidylethanolamine, diphosphatidylglycerol and sphingoglycolipid. On the basis of dDDH and ANI values, as well as the results of genotypic, chemotaxonomic and physiological analyses, strain MAHUQ-71T represents a novel species within the genus Sphingomonas, for which the name Sphingomonas oryzagri sp. nov. is proposed, with MAHUQ-71T (=KACC 22252T=CGMCC 1.19065T) as the type strain.

Roseateles albus sp. nov., Roseateles koreensis sp. nov. and Janthinobacterium fluminis sp. nov., isolated from freshwater at Jucheon River, and emended description of Roseateles aquaticus comb. nov.

Three Gram-stain-negative, facultatively anaerobic, rod-shaped, catalase-positive, oxidase-negative bacterial strains were designated as hw1T, hw8T and hw3T. Strains hw1T, hw8T and hw3T grew at 15-28 °C (optimum, 25 °C), 15-35 °C (optimum, 30 °C) and 4-28 °C (optimum, 20 °C), respectively, and at pH 7.0-12.0 (optimum, pH 9.0), pH 6.0-11.0 (optimum, pH 9.0) and 5.0-12.0 (optimum, pH 7.0), respectively. Additionally, strains hw1T and hw8T only grew when the NaCl concentration was 0 %, while strain hw3T grew at between 0 and 0.5 % (w/v; optimum, 0 %). The average nucleotide identity (ANI) values between strains hw1T, hw8T and the Roseateles type strains ranged from 73.8 to 84.2 %, while the digital DNA-DNA hybridization (dDDH) values ranged from 19.7 to 27.5 %. The ANI values between strain hw3T and the Janthinobacterium type strains ranged from 78.7 to 80.7 %, while dDDH values ranged from 22.3 to 23.0 %. The draft genomes of strains hw1T, hw8T and hw3T consisted of 5.5, 4.4 and 5.9 Mbp, with DNA G+C contents of 61.7, 61.8 and 66.0 mol%, respectively. The results of the dDDH, ANI, phylogenetic, biochemical and physiological analyses indicated that the novel strains were distinct from other members of their genera. Thus, we proposed the names Roseateles albus sp. nov. (type strain hw1T= KACC 22887T= TBRC 16613T), Roseateles koreensis sp. nov. (type strain hw8T= KACC 22885T= TBRC 16614T) and Janthinobacterium fluminis sp. nov. (type strain hw3T= KACC 22886T= TBRC 16615T).

Phylogenomics-based reclassifications in the genus Psychrobacter including emended descriptions of Psychrobacter pacificensis, Psychrobacter proteolyticus and Psychrobacter submarinus.

The taxonomic status of 43 Psychrobacter species was examined based upon the genome sequences of their type strains. Three groups of type strains were found to be conspecific, Psychrobacter salsus Shivaji et al. (Syst Appl Microbiol 27:628-635, 2004. 10.1078/0723202042369956) and Psychrobacter submarinus Romanenko et al. (Int J Syst Evol Microbiol 52:1291-1297, 2002. 10.1099/00207713-52-4-1291); Psychrobacter oceani Matsuyama et al. (Int J Syst Evol Microbiol 65:1450-1455, 2015. 10.1099/ijs.0.000118) and Psychrobacter pacificensis Maruyama et al. (Int J Syst Evol Microbiol 50:835-846, 2000. 10.1099/00207713-50-2-835); and Psychrobacter proteolyticus Denner et al. (Syst Appl Microbiol 24:44-53, 2001. 10.1078/0723-2020-00006), Psychrobacter marincola Romanenko et al. (Int J Syst Evol Microbiol 52:1291-1297, 2002. 10.1099/00207713-52-4-1291) and Psychrobacter adeliensis Shivaji et al. (Syst Appl Microbiol 27:628-635, 2004. 10.1078/0723202042369956). For all three groups, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values are > 97.69% and > 80.2%, respectively. This conclusion is supported by similarities in morphology, growth properties, and fatty acid compositions. Based on this evidence, we propose the reclassification of Psychrobacter salsus Shivaji et al. (Syst Appl Microbiol 27:628-635, 2004. 10.1078/0723202042369956) as a later heterotypic synonym of Psychrobacter submarinus Romanenko et al. (Int J Syst Evol Microbiol 52:1291-1297, 2002. 10.1099/00207713-52-4-1291); Psychrobacter oceani Matsuyama et al. (Int J Syst Evol Microbiol 65:1450-1455, 2015. 10.1099/ijs.0.000118) as a later heterotypic synonym of Psychrobacter pacificensis Maruyama et al. (Int J Syst Evol Microbiol 50:835-846, 2000. 10.1099/00207713-50-2-835), and Psychrobacter marincola Romanenko et al. (Int J Syst Evol Microbiol 52:1291-1297, 2002. 10.1099/00207713-52-4-1291) and Psychrobacter adeliensis Shivaji et al. (Syst Appl Microbiol 27:628-635, 2004. 10.1078/0723202042369956) as later heterotypic synonyms of Psychrobacter proteolyticus Denner et al. (Syst Appl Microbiol 24:44-53, 2001. 10.1078/0723-2020-00006).

Enterococcus faecium 129 BIO 3B is classified as Enterococcus lactis 129 BIO 3B.

Enterococcus faecium 129 BIO 3B is a lactic acid bacterium that has been safely used as a probiotic product for over 100 years. Recently, concerns about its safety have arisen because some species of E. faecium belong to the vancomycin-resistant enterococci. The groups of E. faecium with less pathogenic potential have been split into a separate species (Enterococcus lactis). In this study, I investigated the phylogenetic classification and safety of E. faecium 129 BIO 3B as well as E. faecium 129 BIO 3B-R, which is naturally resistant to ampicillin. Mass spectrometry and basic local alignment search tool analysis using specific gene regions failed to differentiate 3B and 3B-R into E. faecium or E. lactis. However, multilocus sequence typing successfully identified 3B and 3B-R as the same sequence types as E. lactis. Overall genome relatedness indices showed that 3B and 3B-R have high degrees of homology with E. lactis. Gene amplification was confirmed for 3B and 3B-R with E. lactis species-specific primers. The minimum inhibitory concentration of ampicillin was confirmed to be 2 µg/mL for 3B, which is within the safety standard for E. faecium set by the European Food Safety Authority. Based on the above results, E. faecium 129 BIO 3B and E. faecium 129 BIO 3B-R were classified as E. lactis. The absence of pathogenic genes except for fms21 in this study demonstrates that these bacteria are safe for use as probiotics.

Pseudomonas quebecensis sp. nov., a bacterium isolated from root-zone soil of a native legume, Amphicarpaea bracteata (L.) Fernald, in Quebec, Canada.

Four bacterial strains (S1Bt3, S1Bt7, S1Bt30 and S1Bt42T) isolated from soil collected from the rhizosphere of a native legume, Amphicarpaea bracteata, were investigated using a polyphasic approach. Colonies were fluorescent, white-yellowish, circular and convex with regular margins on King's B medium. Cells were Gram-reaction-negative, aerobic, non-spore-forming rods. Oxidase- and catalase-positive. The optimal growth temperature of the strains was 37 °C. Phylogenetic analysis of the 16S rRNA gene sequences placed the strains within the genus Pseudomonas. Analysis of the 16S rRNA-rpoD-gyrB concatenated sequences clustered the strains and well separated from Pseudomonas rhodesiae CIP 104664T and Pseudomonas grimontii CFM 97-514T with the type strains of the closest species. Phylogenomic analysis of 92 up-to-date bacterial core gene and matrix-assisted laser desorption/ionization-time-of-flight MS biotyper data confirmed the distinct clustering pattern of these four strains. Digital DNA-DNA hybridization (41.7 %-31.2 %) and average nucleotide identity (91.1 %-87.0 %) values relative to closest validly published Pseudomonas species were below the species delineation thresholds of 70 and 96 %, respectively. Fatty acid composition results validated the taxonomic position of the novel strains in the genus Pseudomonas. Phenotypic characteristics from carbon utilization tests differentiated the novel strains from closely related Pseudomonas species. In silico prediction of secondary metabolite biosynthesis gene clusters in the whole-genome sequences of the four strains revealed the presence of 11 clusters involved in the production of siderophore, redox-cofactor, betalactone, terpene, arylpolyene and nonribosomal peptides. Based on phenotypic and genotypic data, strains S1Bt3, S1Bt7, S1Bt30 and S1Bt42T represent a novel species for which the name Pseudomonas quebecensis sp. nov. is proposed. The type strain is S1Bt42T (=DOAB 746T=LMG 32141T=CECT 30251T). The genomic DNA G+C content is 60.95 mol%.

Ralstonia chuxiongensis sp. nov., Ralstonia mojiangensis sp. nov., and Ralstonia soli sp. nov., isolated from tobacco fields, are three novel species in the family Burkholderiaceae.

Eight Gram-negative, aerobic, motile with paired polar flagella and rod-shaped bacteria were isolated from six tobacco fields in Yunnan, PR China. 16S rRNA gene sequence analysis revealed that all the strains belonged to the genus Ralstonia. Among them, strain 22TCCZM03-6 had an identical 16S rRNA sequence to that of R. wenshanensis 56D2T, and the other strains were closely related to R. pickettii DSM 6297T (98.34­99.86%), R. wenshanensis 56D2T (98.70­99.64%), and R. insidiosa CCUG 46789T (97.34­98.56%). Genome sequencing yielded sizes ranging from 5.17 to 5.72 Mb, with overall G + C contents of 63.3­64.1%. Pairwise genome comparisons showed that strain 22TCCZM03-6 shared average nucleotide identity (ANI) and digital DNA­DNA hybridization (dDDH) values above the species cut-off with R. wenshanensis 56D2T, suggesting that strain 22TCCZM03-6 is a special strain of the R. wenshanensis. Five strains, including 21MJYT02-10T, 21LDWP02-16, 22TCJT01-1, 22TCCZM01-4, and 22TCJT01-2, had ANI values >95% and dDDH values >70% when compared with each other. These five strains had ANI values of 73.32­94.17% and dDDH of 22.0­55.20% with the type strains of the genus Ralstonia individually, supporting these five strains as a novel species in the genus Ralstonia. In addition, strains 21YRMH01-3T and 21MJYT02-11T represent two independent species. They both had ANI and dDDH values below the thresholds for species delineation when compared with the type species of the genus Ralstonia. In strains 21YRMH01-3T and 21MJYT02-10T, the main fatty acids were summed features 3, 8, and C16:0; however, strain 21MJYT02-11T contained C16:0, cyclo-C17:0, and summed features 3 as major fatty acids. The main polar lipids, including diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine, were identified from strains 21YRMH01-3T, 21MJYT02-10T, and 21MJYT02-11T. The ubiquinones Q-7 and Q-8 were also detected in these strains, with Q-8 being the predominant quinone. Based on the above data, we propose that the eight strains represent one known species and three novel species in the genus Ralstonia, for which the names Ralstonia chuxiongensis sp. nov., Ralstonia mojiangensis sp. nov., and Ralstonia soli sp. nov. are proposed. The type strains are 21YRMH01-3T (=GDMCC 1.3534T = JCM 35818T), 21MJYT02-10T (=GDMCC 1.3531T = JCM 35816T), and 21MJYT02-11T (=GDMCC 1.3532T = JCM 35817T), respectively.

Massilia agrisoli sp. nov., isolated from rhizospheric soil of banana.

A Gram-stain-negative, aerobic, short rod-shaped and motile novel bacterial strain, designated MAHUQ-52T, was isolated from the rhizospheric soil of a banana plant. Colonies grew at 10-35 °C (optimum, 28 °C), pH 6.0-9.5 (optimum, pH 7.0-7.5), and in the presence of 0-1.0 % NaCl (optimum 0 %). The strain was positive for catalase and oxidase tests, as well as hydrolysis of gelatin, casein, starch and Tween 20. Based on the results of phylogenetic analysis using 16S rRNA gene and genome sequences, strain MAHUQ-52T clustered together within the genus Massilia. Strain MAHUQ-52T was closely related to Massilia soli R798T (98.6 %) and Massilia polaris RP-1-19T (98.3 %). The novel strain MAHUQ-52T has a draft genome size of 4 677 454 bp (25 contigs), annotated with 4193 protein-coding genes, 64 tRNA and 19 rRNA genes. The genomic DNA G+C content was 63.0 %. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MAHUQ-52T and closely related type strains were ≤88.4 and 35.8 %, respectively. The only respiratory quinone was ubiquinone-8. The major fatty acids were identified as C16 : 0 and summed feature 3 (C15 : 0 iso 2-OH and/or C16 : 1 ω7c). Strain MAHUQ-52T contained phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol as the major polar lipids. On the basis of dDDH and ANI values, as well as genotypic, chemotaxonomic and physiological data, strain MAHUQ-52T represents a novel species within the genus Massilia, for which the name Massilia agrisoli sp. nov. is proposed, with MAHUQ-52T (=KACC 21999T=CGMCC 1.18577T) as the type strain.