Characterization and description of Gabonibacter chumensis sp. nov., isolated from feces of a patient with non-small cell lung cancer treated with immunotherapy.

A polyphasic taxonomic approach, incorporating analysis of phenotypic features, cellular fatty acid profiles, 16S rRNA gene sequences, and determination of average nucleotide identity (ANI) plus digital DNA-DNA hybridization (dDDH), was applied to characterize an anaerobic bacterial strain designated KD22T isolated from human feces. 16S rRNA gene-based phylogenetic analysis showed that strain KD22T was found to be most closely related to species of the genus Gabonibacter. At the 16S rRNA gene level, the closest species from the strain KD22T corresponded with Gabonibacter massiliensis GM7T, with a similarity of 97.58%. Cells of strain KD22T were Gram-negative coccobacillus, positive for indole and negative for catalase, nitrate reduction, oxidase, and urease activities. The fatty acid analysis demonstrated the presence of a high concentration of iso-C15: 0 (51.65%). Next, the complete whole-genome sequence of strain KD22T was 3,368,578 bp long with 42 mol% of DNA G + C contents. The DDH and ANI values between KD22T and type strains of phylogenetically related species were 67.40% and 95.43%, respectively. These phylogenetic, phenotypic, and genomic results supported the affiliation of strain KD22T as a novel bacterial species within the genus Gabonibacter. The proposed name is Gabonibacter chumensis and the type strain is KD22T (= CSUR Q8104T = DSM 115208 T).

Tractidigestivibacter montrealensis sp. nov., a new member of human gut microbiota isolated from a healthy volunteer.

Strain KD21T, isolated from the fecal sample of a healthy female volunteer, is a strictly anaerobic, non-motile, Gram-staining-positive, saccharolytic small rod that does not produce spores. Strain KD21T was able to grow in the range of temperature 28°C-37°C (optimum, 37 °C), pH 6.0-8.0 (optimum, pH 7.0), and with 0-5.0 g/l NaCl (optimum, 0 g/l NaCl). Bacteria cells reduced nitrates to nitrites. Its major fatty acids were C18:1ω9c, C16:0, C18:0, and summed in feature 8 (C18:1ω7c and/or C18:1ω6c). 16S rRNA gene phylogenetic analysis revealed that KD21T is a member of the genus Tractidigestivibacter and is distinct from any species with validly published names. The sequence showed 98.48% similarity with T. scatoligenes SK9K4T. The DNA G + C content of strain KD21T was 62.6 mol%. The DNA-DNA hybridization and OrthoANI values between strain KD21T and T. scatoligenes SK9K4T were 40.2% and 90.2%, respectively. Differences in phenotypic, phylogenetic, chemotaxonomic, and genomic characteristics indicated that strain KD21T represents a novel species within the genus Tractidigestivibacter. The name T. montrealensis sp. nov. is proposed and the type strain is KD21T (= CSUR Q8103T =  DSM 115111T).

Gut microbiota influence anastomotic healing in colorectal cancer surgery through modulation of mucosal proinflammatory cytokines.

OBJECTIVE: Colorectal cancer (CRC) is the third most diagnosed cancer, and requires surgical resection and reconnection, or anastomosis, of the remaining bowel to re-establish intestinal continuity. Anastomotic leak (AL) is a major complication that increases mortality and cancer recurrence. Our objective is to assess the causal role of gut microbiota in anastomotic healing. DESIGN: The causal role of gut microbiota was assessed in a murine AL model receiving faecal microbiota transplantation (FMT) from patients with CRC collected before surgery and who later developed or not, AL. Anastomotic healing and gut barrier integrity were assessed after surgery. Bacterial candidates implicated in anastomotic healing were identified using 16S rRNA gene sequencing and were isolated from faecal samples to be tested both in vitro and in vivo. RESULTS: Mice receiving FMT from patients that developed AL displayed poor anastomotic healing. Profiling of gut microbiota of patients and mice after FMT revealed correlations between healing parameters and the relative abundance of Alistipes onderdonkii and Parabacteroides goldsteinii. Oral supplementation with A. onderdonkii resulted in a higher rate of leaks in mice, while gavage with P. goldsteinii improved healing by exerting an anti-inflammatory effect. Patients with AL and mice receiving FMT from AL patients presented upregulation of mucosal MIP-1α, MIP-2, MCP-1 and IL-17A/F before surgery. Retrospective analysis revealed that patients with AL present higher circulating neutrophil and monocyte counts before surgery. CONCLUSION: Gut microbiota plays an important role in surgical colonic healing in patients with CRC. The impact of these findings may extend to a vast array of invasive gastrointestinal procedures.

A Natural Polyphenol Exerts Antitumor Activity and Circumvents Anti-PD-1 Resistance through Effects on the Gut Microbiota.

Several approaches to manipulate the gut microbiome for improving the activity of cancer immune-checkpoint inhibitors (ICI) are currently under evaluation. Here, we show that oral supplementation with the polyphenol-rich berry camu-camu (CC; Myrciaria dubia) in mice shifted gut microbial composition, which translated into antitumor activity and a stronger anti-PD-1 response. We identified castalagin, an ellagitannin, as the active compound in CC. Oral administration of castalagin enriched for bacteria associated with efficient immunotherapeutic responses (Ruminococcaceae and Alistipes) and improved the CD8+/FOXP3+CD4+ ratio within the tumor microenvironment. Moreover, castalagin induced metabolic changes, resulting in an increase in taurine-conjugated bile acids. Oral supplementation of castalagin following fecal microbiota transplantation from ICI-refractory patients into mice supported anti-PD-1 activity. Finally, we found that castalagin binds to Ruminococcus bromii and promoted an anticancer response. Altogether, our results identify castalagin as a polyphenol that acts as a prebiotic to circumvent anti-PD-1 resistance. SIGNIFICANCE: The polyphenol castalagin isolated from a berry has an antitumor effect through direct interactions with commensal bacteria, thus reprogramming the tumor microenvironment. In addition, in preclinical ICI-resistant models, castalagin reestablishes the efficacy of anti-PD-1. Together, these results provide a strong biological rationale to test castalagin as part of a clinical trial. This article is highlighted in the In This Issue feature, p. 873.

Bacterial Vaginosis: What Do We Currently Know?

The vaginal microbiome is a well-defined compartment of the human microbiome. It has unique conditions, characterized by the dominance of one bacterial species, the Lactobacilli. This microbiota manifests itself by a low degree of diversity and by a strong dynamic of change in its composition under the influence of various exogenous and endogenous factors. The increase in diversity may paradoxically be associated with dysbiosis, such as bacterial vaginosis (BV). BV is the result of a disturbance in the vaginal ecosystem; i.e., a sudden replacement of Lactobacilli by anaerobic bacteria such as Gardnerella vaginalis, Atopobium vaginae, Ureaplasma urealyticum, Mycoplasma hominis, and others. It is the most common cause of vaginal discharge in women of childbearing age, approximately 30% of all causes. The etiology of this dysbiosis remains unknown, but its health consequences are significant, including obstetrical complications, increased risk of sexually transmitted infections and urogenital infections. Its diagnosis is based on Amsel's clinical criteria and/or a gram stain based on the Nugent score. While both of these methods have been widely applied worldwide for approximately three decades, Nugent score are still considered the "gold standard" of BV diagnostic tools. Given the limitations of these tools, methods based on molecular biology have been developed as alternative rational strategies for the diagnosis of BV. The treatment of BV aims at restoring the balance of the vaginal flora to stop the proliferation of harmful microorganisms. Prescription of antibiotics such as metronidazole, clindamycin, etc. is recommended. Faced with the considerable uncertainty about the cause of BV, the high rate of recurrence, the unacceptable treatment options, and clinical management which is often insensitive and inconsistent, research on this topic is intensifying. Knowledge of its composition and its associated variations represents the key element in improving the therapeutic management of patients with the most suitable treatments possible.

Vaginimicrobium propionicum gen. nov., sp. nov., a novel propionic acid bacterium derived from human vaginal discharge.

A Gram-stain-positive anaerobic rod-shaped bacterium, designated strain Marseille-P3275T, was isolated using culturomics from the vaginal discharge of healthy French woman. Marseille-P3275T was non-motile and did not form spores. Cells had neither catalase nor oxidase activity. The major fatty acids were C16 : 0 (29 %), C18:1ω9 (18 %), and iso-C15 : 0 (17 %). The genomic DNA G+C content was 50.64 mol%. The phylogenetic analysis based on 16S rRNA gene sequence indicated that Marseille-P3275T was related to members of the family Propionibacteriaceae (between 90.32-92.92 % sequence similarity) with formation of a clade with the monospecific genus Propionimicrobium (type species Propionimicrobium lymphophilum). On the basis of these phylogenetic and phenotypic differences, Marseille-P3275T was classified in a novel genus, Vaginimicrobium, as Vaginimicrobium propionicum gen. nov., sp. nov. The type strain is Marseille-P3275T (=CSUR P3275T=CECT 9677T).

Description of Janibacter massiliensis sp. nov., cultured from the vaginal discharge of a patient with bacterial vaginosis.

Strain Marseille-P4121T was isolated from a vaginal sample of a 45-year-old French woman with bacterial vaginosis. It is a Gram-positive, asporogenous, non-motile and aerobic bacterium. Strain Marseille-P4121T exhibits 98.2% 16S rRNA sequence similarity with Janibacter alkaliphilus strain SCSIO 10480T, a phylogenetically closely related species with standing in nomenclature. Its major fatty acids were identified as C18:1ω9 (34.4%), C16:0 (30.1%), and C18:0 (19%). The draft genome size of strain Marseille-P4121T is 2,452,608 bp long with a 72.5% G+C content and contains 2351 protein-coding genes and 49 RNA genes including 3 rRNA genes. We propose that strain Marseille-P4121T (= CECT 9671T = CSUR P4121T) is the type strain of the new species Janibacter massiliensis sp. nov.

Collinsella vaginalis sp. nov. strain Marseille-P2666T, a new member of the Collinsella genus isolated from the genital tract of a patient suffering from bacterial vaginosis.

A strictly anaerobic, Gram-stain-positive, non motile and non-spore-forming rod-shaped bacterium, strain Marseille-P2666T, was isolated using the culturomics approach from a vaginal sample of a French patient suffering from bacterial vaginosis. Cells were saccharolytic and were negative for catalase, oxidase, urease, nitrate reduction, indole production, hydrolysis of aesculin and gelatin. Strain Marseille-P2666T exhibited 97.04 % 16S rRNA sequence similarity to Collinsella tanakaei type strain YIT 12063T, the phylogenetically closest species with standing in nomenclature. The major fatty acids were C18:1ω9 (38 %), C16 : 0 (24 %) and C18 : 0 (19 %). The G+C content of the genome sequence of strain Marseille-P2666T is 64.6 mol%. On the basis of its phenotypic, phylogenetic and genomic features, strain Marseille-P2666T (=CSUR 2666T=DSM103342T) was classified as type strain of a novel species within the genus Collinsella for which the name Collinsella vaginalis sp. nov. is proposed.

Description of three new Peptoniphilus species cultured in the vaginal fluid of a woman diagnosed with bacterial vaginosis: Peptoniphilus pacaensis sp. nov., Peptoniphilus raoultii sp. nov., and Peptoniphilus vaginalis sp. nov.

Three previously unidentified Gram-positive anaerobic coccoid bacteria, strains KhD-2T , KHD4T , and Kh-D5T , isolated from a vaginal swab, were characterized using the taxonogenomics concept. The phylogenic analysis, phenotypic characteristics, and genotypic data presented in this report attest that these three bacteria are distinct from previously known bacterial species with standing in nomenclature and represent three new Peptoniphilus species. Strain KhD-2T is most closely related to Peptoniphilus sp. DNF00840 and Peptoniphilus harei (99.7% and 98.2% identity, respectively); strain KHD4T to Peptoniphilus lacrimalis (96%) and strain Kh-D5T to Peptoniphilus coxii (97.2%). Strains KhD-2T , KHD4T , and Kh-D5T DNA G+C contents are, respectively, 34.23%, 31.87%, and 49.38%; their major fatty acid was C16:0 (41.6%, 32.0%, and 36.4%, respectively). We propose that strains KhD-2T (=CSUR P0125 = DSM 101742), KHD4T (=CSUR P0110 = CECT 9308), and Kh-D5T (=CSUR P2271 = DSM 101839) be the type strains of the new species for which the names Peptoniphilus vaginalis sp. nov., Peptoniphilus raoultii sp. nov., and Peptoniphilu pacaensis sp. nov., are proposed, respectively.

Characterization of a novel Gram-stain-positive anaerobic coccus isolated from the female genital tract: Genome sequence and description of Murdochiella vaginalis sp. nov.

Strain Marseille-P2341T , a nonmotile, nonspore-forming, Gram-stain-positive anaerobic coccus, was isolated in the vaginal specimen of a patient with bacterial vaginosis using culturomics. Its growth occurred at temperatures ranging from 25 to 42°C, with pH between 6.5 and 8.5, and at NaCl concentrations lower than 5%. The major fatty acids were C18:1n9 (27.7%) and C16:0 (24.4%). Its genome is 1,671,491 bp long with 49.48 mol% of G+C content. It is composed of 1,501 genes: 1,446 were protein-coding genes and 55 were RNAs. Strain Marseille-P2341T shared 97.3% of 16S rRNA gene sequence similarity with Murdochiella asaccharolytica, the phylogenetically closest species. These results enabled the classification of strain Marseille-P2341T as a new species of the genus Murdochiella for which we proposed the name Murdochiella vaginalis sp. nov. The type strain is strain Marseille-P2341T (=DSM 102237, =CSUR P2341).

Draft Genome Sequence of Ezakiella peruensis Strain M6.X2, a Human Gut Gram-Positive Anaerobic Coccus.

We report here the draft genome sequence of Ezakiella peruensis strain M6.X2T The draft genome is 1,672,788 bp long and harbors 1,589 predicted protein-encoding genes, including 26 antibiotic resistance genes with 1 gene encoding vancomycin resistance. The genome also exhibits 1 clustered regularly interspaced short palindromic repeat region and 333 genes acquired by horizontal gene transfer.

Corynebacterium fournierii sp. nov., isolated from the female genital tract of a patient with bacterial vaginosis.

Strain Marseille-P2948T, a novel Gram-positive, catalase-positive bacterium was isolated from a vaginal sample of a patient with bacterial vaginosis. It was characterised using the taxonogenomic approach. Phylogenetic analysis revealed that the 16S rRNA and the rpoB genes exhibit 98.7 and 93.4% similarity, respectively, with those of Corynebacterium ureicelerivorans strain IMMIB RIV-301T. Biochemical tests of strain Marseille-P2948T gave results that were similar to those of other validly named Corynebacterium species, whereas chemotaxonomic tests showed the presence of C16:0, C18:1n9, C18:0, and C18:2n6 in the fatty acid profile. The draft genome of strain Marseille-P2948T is 2,383,644 bp long in size with a G+C content of 65.03%. Of the 2210 predicted genes, 2147 are protein-coding genes and 63 are RNAs. Based on phenotypic, phylogenic and genomic results, it was concluded that the isolate represents a new species within the genus Corynebacterium. The name Corynebacterium fournierii sp. nov. is proposed and the type strain is Marseille-P2948T (= CSUR P2948 = DSM 103271).

Microbial Culturomics Broadens Human Vaginal Flora Diversity: Genome Sequence and Description of Prevotella lascolaii sp. nov. Isolated from a Patient with Bacterial Vaginosis.

Microbial culturomics is a new subfield of postgenomic medicine and omics biotechnology application that has broadened our awareness on bacterial diversity of the human microbiome, including the human vaginal flora bacterial diversity. Using culturomics, a new obligate anaerobic Gram-stain-negative rod-shaped bacterium designated strain khD1T was isolated in the vagina of a patient with bacterial vaginosis and characterized using taxonogenomics. The most abundant cellular fatty acids were C15:0 anteiso (36%), C16:0 (19%), and C15:0 iso (10%). Based on an analysis of the full-length 16S rRNA gene sequences, phylogenetic analysis showed that the strain khD1T exhibited 90% sequence similarity with Prevotella loescheii, the phylogenetically closest validated Prevotella species. With 3,763,057 bp length, the genome of strain khD1T contained (mol%) 48.7 G + C and 3248 predicted genes, including 3194 protein-coding and 54 RNA genes. Given the phenotypical and biochemical characteristic results as well as genome sequencing, strain khD1T is considered to represent a novel species within the genus Prevotella, for which the name Prevotella lascolaii sp. nov. is proposed. The type strain is khD1T ( = CSUR P0109, = DSM 101754). These results show that microbial culturomics greatly improves the characterization of the human microbiome repertoire by isolating potential putative new species. Further studies will certainly clarify the microbial mechanisms of pathogenesis of these new microbes and their role in health and disease. Microbial culturomics is an important new addition to the diagnostic medicine toolbox and warrants attention in future medical, global health, and integrative biology postgraduate teaching curricula.

Characterization of a New Ezakiella Isolated from the Human Vagina: Genome Sequence and Description of Ezakiella massiliensis sp. nov.

The study of the vaginal microbiota using the "culturomics concept" allowed us to isolate, from the vaginal swab of an asymptomatic 20-year-old woman who had sexual relations with another woman with bacterial vaginosis, an unknown Gram-positive anaerobic coccus-shaped bacterium that was designated strain Marseille-P2951T and characterized using taxono-genomics. Strain Marseille-P2951T is non-motile and non-spore forming and exhibits catalase and oxidase activities. Its 16S rRNA gene-based identification showed 98.5% identity with Ezakiella peruensis, the phylogenetically closest species. The major fatty acids are C18:1n9 (58%) and C16:0 (22%). With a 1,741,785 bp length, the G+C content of the genome is 36.69%. Of a total of 1657 genes, 1606 are protein-coding genes and 51 RNAs. Also, 1123 genes are assigned a putative function and 127 are ORFans. Phenotypic, phylogenetic, and genomics analyses revealed that strain Marseille-P2951T (=CSUR P2951 =DSM 103122) is distinct and represents a new species of the genus Ezakiella, for which the name Ezakiella massiliensis sp. nov. is proposed.

Olegusella massiliensis gen. nov., sp. nov., strain KHD7T, a new bacterial genus isolated from the female genital tract of a patient with bacterial vaginosis.

Strain KHD7T, a Gram-stain-positive rod-shaped, non-sporulating, strictly anaerobic bacterium, was isolated from the vaginal swab of a woman with bacterial vaginosis. We studied its phenotypic characteristics and sequenced its complete genome. The major fatty acids were C16:0 (44%), C18:2n6 (22%), and C18:1n9 (14%). The 1,806,744 bp long genome exhibited 49.24% G+C content; 1549 protein-coding and 51 RNA genes. Strain KHD7T exhibited a 93.5% 16S rRNA similarity with Olsenella uli, the phylogenetically closest species in the family Coriobacteriaceae. Therefore, strain KHD7T is sufficiently distinct to represent a new genus, for which we propose the name Olegusella massiliensis gen. nov., sp. nov. The type strain is KHD7T.

Culture of previously uncultured members of the human gut microbiota by culturomics.

Metagenomics revolutionized the understanding of the relations among the human microbiome, health and diseases, but generated a countless number of sequences that have not been assigned to a known microorganism1. The pure culture of prokaryotes, neglected in recent decades, remains essential to elucidating the role of these organisms2. We recently introduced microbial culturomics, a culturing approach that uses multiple culture conditions and matrix-assisted laser desorption/ionization-time of flight and 16S rRNA for identification2. Here, we have selected the best culture conditions to increase the number of studied samples and have applied new protocols (fresh-sample inoculation; detection of microcolonies and specific cultures of Proteobacteria and microaerophilic and halophilic prokaryotes) to address the weaknesses of the previous studies3-5. We identified 1,057 prokaryotic species, thereby adding 531 species to the human gut repertoire: 146 bacteria known in humans but not in the gut, 187 bacteria and 1 archaea not previously isolated in humans, and 197 potentially new species. Genome sequencing was performed on the new species. By comparing the results of the metagenomic and culturomic analyses, we show that the use of culturomics allows the culture of organisms corresponding to sequences previously not assigned. Altogether, culturomics doubles the number of species isolated at least once from the human gut.