The influence of microbial dysbiosis on immunochemotherapy-related efficacy and safety in diffuse large B-cell lymphoma.

The gut microbiome influences cancer development and the efficacy and safety of chemotherapy but little is known about its effects on lymphoma. We obtained stool samples from treatment-naive, newly diagnosed patients with diffuse large B-cell lymphoma (DLBCL) (n = 189). We first performed 16S ribosomal RNA gene sequencing (n = 158) and then conducted whole-genome shotgun sequencing on additional samples (n = 106). We compared the microbiome data from these patients with data from healthy controls and assessed whether microbiome characteristics were associated with treatment outcomes. The alpha diversity was significantly lower in patients with DLBCL than in healthy controls (P < .001), and the microbial composition differed significantly between the groups (P < .001). The abundance of the Enterobacteriaceae family belonging to the Proteobacteria phylum was markedly higher in patients than in healthy controls. Functional analysis of the microbiome revealed an association with opportunistic pathogenesis through type 1 pili, biofilm formation, and antibiotics resistance. Enterobacteriaceae members were significantly enriched in patients who experienced febrile neutropenia and in those who experienced relapse or progression (P < .001). Interestingly, greater abundance of Enterobacteriaceae correlated with shorter progression-free survival (P = .007). The cytokine profiles of patients whose microbiome was enriched with Enterobacteriaceae were significantly associated with interleukin 6 (P = .035) and interferon gamma (P = .045) levels. In summary, patients with DLBCL exhibited gut microbial dysbiosis. The abundance of Enterobacteriaceae correlated with treatment outcomes and febrile neutropenia. Further study is required to elucidate the origin and role of gut dysbiosis in DLBCL.

Host phylogeny, habitat, and diet are main drivers of the cephalopod and mollusk gut microbiome.

BACKGROUND: Invertebrates are a very attractive subject for studying host-microbe interactions because of their simple gut microbial community and host diversity. Studying the composition of invertebrate gut microbiota and the determining factors is essential for understanding their symbiotic mechanism. Cephalopods are invertebrates that have similar biological properties to vertebrates such as closed circulation system, an advanced nervous system, and a well-differentiated digestive system. However, it is not currently known whether their microbiomes have more in common with vertebrates or invertebrates. This study reports on the microbial composition of six cephalopod species and compares them with other mollusk and marine fish microbiomes to investigate the factors that shape the gut microbiota. RESULTS: Each cephalopod gut consisted of a distinct consortium of microbes, with Photobacterium and Mycoplasma identified as core taxa. The gut microbial composition of cephalopod reflected their host phylogeny, the importance of which was supported by a detailed oligotype-level analysis of operational taxonomic units assigned to Photobacterium and Mycoplasma. Photobacterium typically inhabited multiple hosts, whereas Mycoplasma tended to show host-specific colonization. Furthermore, we showed that class Cephalopoda has a distinct gut microbial community from those of other mollusk groups or marine fish. We also showed that the gut microbiota of phylum Mollusca was determined by host phylogeny, habitat, and diet. CONCLUSION: We have provided the first comparative analysis of cephalopod and mollusk gut microbial communities. The gut microbial community of cephalopods is composed of distinctive microbes and is strongly associated with their phylogeny. The Photobacterium and Mycoplasma genera are core taxa within the cephalopod gut microbiota. Collectively, our findings provide evidence that cephalopod and mollusk gut microbiomes reflect host phylogeny, habitat, and diet. It is hoped that these data can contribute to future studies on invertebrate-microbe interactions.

Lysobacter ciconiae sp. nov., and Lysobacter avium sp. nov., isolated from the faeces of an Oriental stork.

Two Gram-stain-negative, mesophilic, strictly aerobic, nonspore forming, and yellow-pigmented strains with rod-shaped cells, designated H21R20T and H23M41T, were isolated from the faeces of an Oriental stork (Ciconia boyciana). Based on 16S rRNA gene sequences, both strains showed the highest similarity (98.3-98.4%) to the type strain of Lysobacter concretionis. Phylogenetic analysis based on the 16S rRNA genes and 92 bacterial core genes showed that strains H21R20T and H23M41T were robustly clustered with L. concretionis Ko07T. Whole genome sequencing revealed that the genomes of both strains were approximately 2.9 Mb in size. The DNA G + C contents of the H21R20T and H23M41T strains were 67.3 and 66.6%, respectively. The two strains showed 80.1-81.7% average nucleotide identity with L. concretionis Ko07T. Strain H21R20T grew optimally at 30°C and pH 8.0 and in the presence of 0.5-3% (wt/vol) NaCl, while strain H23M41T grew optimally at 30°C and pH 7.0-8.0 and in the presence of 0-3% (wt/vol) NaCl. Both strains possessed iso-C15:0, iso-C16:0 and summed feature 9 (iso-C17:1ω9c and/or C16:010-methyl) as the major cellular fatty acids, ubiquinone Q-8 as a predominant quinone, and diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine as the major polar lipids. A multifaceted investigation demonstrated that strains H21R20T and H23M41T represent novel species of the genus Lysobacter, for which we propose the names Lysobacter ciconiae sp. nov. and Lysobacter avium sp. nov. for strains H21R20T (= KCTC 82316T = JCM 34832T) and H23M41T (= KCTC 62676T = JCM 33223T), respectively.

Description of Polaribacter batillariae sp. nov., Polaribacter cellanae sp. nov., and Polaribacter pectinis sp. nov., novel bacteria isolated from the gut of three types of South Korean shellfish.

Three aerobic, Gram-negative, and rod-shaped bacterial strains, designated strains G4M1T, SM13T, and L12M9T, were isolated from the gut of Batillaria multiformis, Cellana toreuma, and Patinopecten yessoensis collected from the Yellow Sea in South Korea. All the strains grew optimally at 25°C, in the presence of 2% (w/v) NaCl, and at pH 7. These three strains, which belonged to the genus Polaribacter in the family Flavobacteriaceae, shared < 98.8% in 16S rRNA gene sequence and < 86.68% in whole-genome sequence with each other. Compared with the type strains of Polaribacter, isolates showed the highest sequence similarity to P. haliotis KCTC 52418T (< 98.68%), followed by P. litorisediminis KCTC 52500T (< 98.13%). All the strains contained MK-6 as their predominant menaquinone and iso-C15:0 as their major fatty acid. Moreover, all the strains had phosphatidylethanolamine as their polar lipid component. In addition, strain G4M1T had two unidentified lipids and three unidentified aminolipids, strain SM13T had three unidentified lipids and three unidentified aminolipids, and strain L12M9T had three unidentified lipids and one unidentified aminolipid. The DNA G + C contents of strains G4M1T, SM13T, and L12M9T were 31.0, 30.4, and 29.7 mol%, respectively. Based on phenotypic, phylogenetic, chemotaxonomic, and genotypic findings, strains G4M1T (= KCTC 82388T = DSM 112372T), SM13T (= KCTC 82389T = DSM 112373T), and L12M9T (= KCTC 62751T = DSM 112374T) were classified into the genus Polaribacter as the type strains of novel species, for which the names Polaribacter batillariae sp. nov., Polaribacter cellanae sp. nov., and Polaribacter pectinis sp. nov., respectively, have been proposed.

Nocardioides palaemonis sp. nov. and Tessaracoccus palaemonis sp. nov., isolated from the gastrointestinal tract of lake prawn.

Two novel Gram-stain-positive, non-motile and non-spore-forming bacterial strains, designated J2M5T and J1M15T, were isolated from the gastrointestinal tract of a lake prawn Palaemon paucidens. Strain J2M5T was an obligately aerobic bacterium that formed milky-coloured colonies and showed a rod-coccus cell cycle, while strain J1M15T was a facultatively aerobic bacterium that formed orangish-yellow-coloured colonies and showed rod-shaped cells. Strains J2M5T and J1M15T showed the highest 16S rRNA gene sequence similarity to Nocardioides ganghwensis JC2055T (98.63 %) and Tessaracoccus flavescens SST-39T (98.08 %), respectively. The whole-genome sequence of strain J2M5T was 4.52 Mbp in size and the genomic G+C content directly calculated from the genome sequence of strain J2M5T was 72.5 mol%. The whole-genome sequence of strain J1M15T was 3.20 Mbp in size and the genomic G+C content directly calculated from the genome sequence of strain J1M15T was 69.6mol %. Strains J2M5T and J1M15T showed high OrthoANI similarity to N. ganghwensis JC2055T (83.6 %) and T. flavescens (77.2 %), respectively. We analysed the genome sequences of strains J2M5T and J1M15T in terms of carbohydrate-active enzymes, antibiotic resistance genes and virulence factor genes. Strains J2M5T and J1M15T contained MK-8 (H4) and MK-9 (H4) as the predominant respiratory quinones, respectively. The major polar lipids of both strains were phosphatidylglycerol and diphosphatidylglycerol. Additionally, strain J2M5T possessed phosphatidylcholine, phosphatidylserine and phosphatidylethanolamine. The cellular sugar components of strain J2M5T were ribose, mannose, glucose and galactose, and its cellular amino acid components were l-alanine and l-lysine. The cellular sugar components of strain J1M15T were rhamnose, ribose, mannose and glucose, and its cellular amino acid component was l-alanine. The major cellular fatty acids of strains J2M5T and J1M15T were iso-C16 : 0 and anteiso-C15 : 0, respectively. The multiple taxonomic analyses indicated that strains J2M5T and J1M15T represent novel species of the genus Nocardioides and Tessaracoccus, respectively. We propose the names Nocardioides palaemonis sp. nov. and Tessaracoccus palaemonis sp. nov. for strain J2M5T (=KCTC 49461T=CCUG 74767T) and strain J1M15T (=KCTC 49462T=CCUG 74766T), respectively.

Anaerostipes hominis sp. nov., a novel butyrate-producing bacteria isolated from faeces of a patient with Crohn's disease.

Cultivation and isolation of gut bacteria are necessary for understanding their role in the intestinal ecosystem. We isolated a novel bacterium, designated strain BG01T, from the faeces of a patient with Crohn's disease. Strain BG01T was a strictly anaerobic, rod-shaped, Gram-variable and endospore-forming bacterium. Strain BG01T possessed C12 : 0, C18 : 0 dimethyl aldehyde (DMA) and C18 : 1 ω9c DMA as predominant cellular fatty acids and meso-diaminopimelic acid as a diagnostic diamino acid. Strain BG01T grew at 15-45 °C (optimum, 37 °C), with 0-4 % (w/v) NaCl (optimum, 0-1 %), at pH 6-10 (optimum, pH 7) and was resistant to bile salt, but not to ampicillin, metronidazole, vancomycin and cefoperazone. Butyrate, propionate, oxalacetate and fumarate were produced as fermentation end products from Gifu anaerobic medium broth. Strain BG01T showed 97.7 % 16S rRNA gene sequence similarity, and 92.0 and 48.5 % of average nucleotide identity and digital DNA-DNA hybridization values, respectively, with Anaerostipes caccae KCTC 15019T. Genomic analysis indicated that strain BG01T had a butyrate-producing pathway. The genomic G+C content of the strain was 43.5 mol%. Results of the phenotypic, phylogenetic and genotypic analyses indicated that strain BG01T represents a novel butyrate-producing species of the genus Anaerostipes, for which the name Anaerostipes hominis sp. nov. is proposed. The type strain is BG01T (=KCTC 15617T=JCM 32275T).

Oral microbiome associated with lymph node metastasis in oral squamous cell carcinoma.

Oral microbiota can alter cancer susceptibility and progression by modulating metabolism and inflammation. We assessed the association between the oral microbiome and lymph node (LN) metastasis in oral squamous cell carcinoma (OSCC). We collected a total of 54 saliva samples from patients with OSCC before surgery. LN metastasis was assessed based on postoperative pathological examination. We used QIIME2, linear discriminant analysis effect size (LEfSe), and PICRUSt2 methods to analyze microbial dysbiosis. A random forest classifier was used to assess whether the oral microbiome could predict LN metastasis. Among the 54 OSCC samples, 20 had LN metastasis, and 34 had no evidence of metastasis. There was a significant difference in ß-diversity between the metastasis and no metastasis groups. Through LEfSe analysis, the metastasis group was enriched in the genera Prevotella, Stomatobaculum, Bifidobacterium, Peptostreptococcaceae, Shuttleworthia and Finegoldia. Pathways related to signal peptidase II were predominant in the no metastasis group. The RF model showed a modestly high accuracy for predicting metastasis. Differences in microbial community composition and functions were observed in the oral microbiome of patients with OSCC with and without LN metastasis. However, the finding that specific taxa may be associated with LN metastasis should be verified in a further prospective study.

Description of Ornithinimicrobium ciconiae sp. nov., and Ornithinimicrobium avium sp. nov., isolated from the faeces of the endangered and near-threatened birds.

Phenotypic and genomic analyses were performed to characterize two novel species, H23M54T and AMA3305T, isolated from the faeces of the Oriental stork (Ciconia boyciana) and the cinereous vulture (Aegypius monachus), respectively. Strains H23M54T and AMA3305T showed the highest similarities of 16S rRNA gene sequences and complete genome sequences with Ornithinimicrobium cavernae CFH 30183T (98.5% of 16S rRNA gene sequence similarity and 82.1% of average nucleotide identity, ANI) and O. pekingense DSM 21552T (98.5% of 16S rRNA gene sequence similarity and 82.3% of ANI), respectively. Both strains were Gram-stain-positive, obligate aerobes, non-motile, non-spore-forming, and coccoid- and rodshaped. Strain H23M54T grew optimally at 25-30°C and pH 8.0 and in the presence of 1.5-2% (wt/vol) NaCl, while strain AMA3305T grew optimally at 30°C and pH 7.0 and in the presence of 1-3% (wt/vol) NaCl. Both strains had iso-C15:0, iso-C16:0, and summed feature 9 (iso-C17:1ω9c and/or C16:0 10-methyl) as major cellular fatty acids. MK-8 (H4) was identified as the primary respiratory quinone in both strains. Strains H23M54T and AMA3305T possessed diphosphatidylglycerol and phosphatidylglycerol as major polar lipids. Moreover, strains H23M54T and AMA3305T commonly contained ribose and glucose as major sugars and L-ornithine, L-alanine, glycine, and aspartic acid as major amino acids. The polyphasic taxonomic data indicate that strains H23M54T and AMA3305T represent novel species of the genus Ornithinimicrobium. We propose the names Ornithinimicrobium ciconiae sp. nov. and Ornithinimicrobium avium sp. nov. for strains H23M54T (= KCTC 49151T = JCM 33221T) and AMA3305T (= KCTC 49180T = JCM 32873T), respectively.

Host habitat is the major determinant of the gut microbiome of fish.

BACKGROUND: Our understanding of the gut microbiota of animals is largely based on studies of mammals. To better understand the evolutionary basis of symbiotic relationships between animal hosts and indigenous microbes, it is necessary to investigate the gut microbiota of non-mammalian vertebrate species. In particular, fish have the highest species diversity among groups of vertebrates, with approximately 33,000 species. In this study, we comprehensively characterized gut bacterial communities in fish. RESULTS: We analyzed 227 individual fish representing 14 orders, 42 families, 79 genera, and 85 species. The fish gut microbiota was dominated by Proteobacteria (51.7%) and Firmicutes (13.5%), different from the dominant taxa reported in terrestrial vertebrates (Firmicutes and Bacteroidetes). The gut microbial community in fish was more strongly shaped by host habitat than by host taxonomy or trophic level. Using a machine learning approach trained on the microbial community composition or predicted functional profiles, we found that the host habitat exhibited the highest classification accuracy. Principal coordinate analysis revealed that the gut bacterial community of fish differs significantly from those of other vertebrate classes (reptiles, birds, and mammals). CONCLUSIONS: Collectively, these data provide a reference for future studies of the gut microbiome of aquatic animals as well as insights into the relationship between fish and their gut bacteria, including the key role of host habitat and the distinct compositions in comparison with those of mammals, reptiles, and birds. Video Abstract.

Chitinibacter bivalviorum sp. nov., isolated from the gut of the freshwater mussel Anodonta arcaeformis.

A novel Gram-stain-negative, aerobic, rod-shaped bacterium with a single polar flagellum, designated strain 2T18T, was isolated from the gut of the freshwater mussel Anodonta arcaeformis collected in the Republic of Korea. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain belonged to the genus Chitinibacter. Strain 2T18T formed a monophyletic clade with Chitinibacter fontanus KCTC 42982T, C. tainanensis KACC 11706T and C. alvei KCTC 23839T, with sequence similarities of 98.5, 98.4 and 95.9 %, respectively. Strain 2T18T exhibited optimal growth at 30 °C, at pH 8 and with 0.5 % (w/v) NaCl. The major isoprenoid quinone was ubiquinone-8 (Q-8). The predominant fatty acids were summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) and C16 : 0. The polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified lipid, three unidentified phospholipids and two unidentified aminophospholipids. The G+C content of the genomic DNA was 50.6 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strains 2T18T and C. fontanus KCTC 42982T were below the thresholds used for the delineation of a novel species. Based on the phylogenetic, phenotypic, chemotaxonomic and genotypic characteristics, strain 2T18T represents a novel species of the genus Chitinibacter, for which the name Chitinibacter bivalviorum sp. nov. is proposed. The type strain is 2T18T (=KCTC 72821T=CCUG 74764T).

Pathogenomics of Streptococcus ilei sp. nov., a newly identified pathogen ubiquitous in human microbiome.

Viridans group streptococci are a serious health concern because most of these bacteria cause life-threatening infections, especially in immunocompromised and hospitalized individuals. We focused on two alpha-hemolytic Streptococcus strains (I-G2 and I-P16) newly isolated from an ileostomy effluent of a colorectal cancer patient. We examined their pathogenic potential by investigating their prevalence in human and assessing their pathogenicity in a mouse model. We also predicted their virulence factors and pathogenic features by using comparative genomic analysis and in vitro tests. Using polyphasic and systematic approaches, we identified the isolates as belonging to a novel Streptococcus species and designated it as Streptococcus ilei. Metagenomic survey based on taxonomic assignment of datasets from the Human Microbiome Project revealed that S. ilei is present in most human population and at various body sites but is especially abundant in the oral cavity. Intraperitoneal injection of S. ilei was lethal to otherwise healthy C57BL/6J mice. Pathogenomics and in vitro assays revealed that S. ilei possesses a unique set of virulence factors. In agreement with the in vivo and in vitro data, which indicated that S. ilei strain I-G2 is more pathogenic than strain I-P16, only the former displayed the streptococcal group A antigen. We here newly identified S. ilei sp. nov., and described its prevalence in human, virulence factors, and pathogenicity. This will help to prevent S. ilei strain misidentification in the future, and improve the understanding and management of streptococcal infections.

Mitofusin-2 boosts innate immunity through the maintenance of aerobic glycolysis and activation of xenophagy in mice.

Mitochondrial function and innate immunity are intimately linked; however, the mechanisms how mitochondrion-shaping proteins regulate innate host defense remains largely unknown. Herein we show that mitofusin-2 (MFN2), a mitochondrial fusion protein, promotes innate host defense through the maintenance of aerobic glycolysis and xenophagy via hypoxia-inducible factor (HIF)-1α during intracellular bacterial infection. Myeloid-specific MFN2 deficiency in mice impaired the antimicrobial and inflammatory responses against mycobacterial and listerial infection. Mechanistically, MFN2 was required for the enhancement of inflammatory signaling through optimal induction of aerobic glycolysis via HIF-1α, which is activated by mitochondrial respiratory chain complex I and reactive oxygen species, in macrophages. MFN2 did not impact mitophagy during infection; however, it promoted xenophagy activation through HIF-1α. In addition, MFN2 interacted with the late endosomal protein Rab7, to facilitate xenophagy during mycobacterial infection. Our findings reveal the mechanistic regulations by which MFN2 tailors the innate host defense through coordinated control of immunometabolism and xenophagy via HIF-1α during bacterial infection.

Brevilactibacter coleopterorum sp. nov., isolated from the intestine of the dark diving beetle Hydrophilus acuminatus, and Weissella coleopterorum sp. nov., isolated from the intestine of the diving beetle Cybister lewisianus.

A polyphasic taxonomic approach was used to characterize two novel bacterial strains, designated as HDW11T and HDW19T, isolated from intestine samples of the dark diving beetle Hydrophilus acuminatus and the diving beetle Cybister lewisianus, respectively. Both isolates were Gram-stain-positive, facultatively anaerobic and non-motile. Strain HDW11T grew optimally at 30 °C, pH 8 and in the presence of 1% (w/v) NaCl. Strain HDW19T grew optimally at 25 °C, pH 7 and in the presence of 0.3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences and genome sequences revealed that strain HDW11T is a member of the genus Brevilactibacter and is closely related to Brevilactibacter flavus VG341T [with 97.9% 16S rRNA sequence identity and 79.1% average nucleotide identity (ANI)], and that strain HDW19T belongs to the genus Weissella and is closely related to W. koreensis KCTC 3621T (with 98.9% 16S rRNA sequence identity and 79.5% ANI). The major cellular fatty acids of strains HDW11T and HDW19T were C18:1 ω9c and anteiso-C15:0, respectively. The sole respiratory quinone of strain HDW11T was MK-9 (H4). The major polar lipid components of strain HDW11T were diphosphatidylglycerol and phosphatidylglycerol, and the major polar lipid component of strain HDW19T was diphosphatidylglycerol. The genomic DNA G+C content of strains HDW11T and HDW19T were 72.1 and 37.2 mol%, respectively. The results of phylogenetic, phenotypic, chemotaxonomic and genotypic analyses suggest that strain HDW11T represents a novel species within the genus Brevilactibacter, and that strain HDW19T represents a novel species within the genus Weissella. We propose the name Brevilactibacter coleopterorum sp. nov. for strain HDW11T (=KACC 21335T=KCTC 49320T=JCM 33680T) and the name Weissella coleopterorum for strain HDW19T (=KACC 21347T=KCTC 43114T=JCM 33684T).

Description of Nocardioides piscis sp. nov., Sphingomonas piscis sp. nov. and Sphingomonas sinipercae sp. nov., isolated from the intestine of fish species Odontobutis interrupta (Korean spotted sleeper) and Siniperca scherzeri (leopard mandarin fish).

A polyphasic taxonomic approach was used to characterize three novel bacterial strains, designated as HDW12AT, HDW-15BT, and HDW15CT, isolated from the intestine of fish species Odontobutis interrupta or Siniperca scherzeri. All isolates were obligate aerobic, non-motile bacteria, and grew optimally at 30°C. Phylogenetic analysis based on 16S rRNA sequences revealed that strain HDW12AT was a member of the genus Nocardioides, and closely related to Nocardioides allogilvus CFH 30205T (98.9% sequence identities). Furthermore, strains HDW15BT and HDW15CT were members of the genus Sphingomonas, and closely related to Sphingomonas lutea JS5T and Sphingomonas sediminicola Dae 20T (97.1% and 97.9% sequence identities), respectively. Strain HDW12AT contained MK-8 (H4), and strains HDW15BT and HDW15CT contained Q-10 as the respiratory quinone. Major polar lipid components of strain HDW12AT were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylinositol, and those of strains HDW15BT and HDW15CT were sphingoglycolipid, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and phosphatidylcholine. The G + C content of strains HDW12AT, HDW15BT, and HDW15CT were 69.7, 63.3, and 65.5%, respectively. The results of phylogenetic, phenotypic, chemotaxonomic, and genotypic analyses suggest that strain HDW12AT represents a novel species within the genus Nocardioides, and strains HDW15BT and HDW15CT represent two novel species within the genus Sphingomonas. We propose the names Nocardioides piscis for strain HDW12AT (= KACC 21336T = KCTC 49321T = JCM 33670T), Sphingomonas piscis for strain HDW15BT (= KACC 21341T = KCTC 72588T = JCM 33738T), and Sphingomonas sinipercae for strain HDW15CT (= KACC 21342T = KCTC 72589T = JCM 33739T).

Calf Diarrhea Caused by Prolonged Expansion of Autochthonous Gut Enterobacteriaceae and Their Lytic Bacteriophages.

Neonatal calf diarrhea is a common disease leading to a major economic loss for cattle producers worldwide. Several infectious and noninfectious factors are implicated in calf diarrhea, but disease control remains problematic because of the multifactorial etiology of the disease. Here, we conducted diagnostic multiplex PCR assay and meta-omics analysis (16S rRNA gene-based metataxonomics and untargeted transcriptional profiling) of rectal content of normal and diarrheic beef calves (n = 111). In the diarrheic calf gut, we detected both microbial compositional dysbiosis (i.e., increased abundances of the family Enterobacteriaceae members and their lytic bacteriophages) and functional dysbiosis (i.e., elevated levels of aerobic respiration and virulence potential). The calf diarrheic transcriptome mirrored the gene expression of the bovine host and was enriched in cellular pathways of sulfur metabolism, innate immunity, and gut motility. We then isolated 12 nontoxigenic Enterobacteriaceae strains from the gut of diarrheic calves. Feeding a strain mixture to preweaning mice resulted in a significantly higher level of fecal moisture content, with decreased body weight gain and shortened colon length. The presented findings suggest that gut inflammation followed by a prolonged expansion of nontoxigenic autochthonous Enterobacteriaceae contributes to the onset of diarrhea in preweaning animals.IMPORTANCE Calf diarrhea is the leading cause of death of neonatal calves worldwide. Several infectious and noninfectious factors are implicated in calf diarrhea, but disease control remains problematic because of the multifactorial etiology of the disease. The major finding of the current study centers around the observation of microbial compositional and functional dysbiosis in rectal samples from diarrheic calves. These results highlight the notion that gut inflammation followed by a prolonged expansion of autochthonous Enterobacteriaceae contributes to the onset of calf diarrhea. Moreover, this condition possibly potentiates the risk of invasion of notorious enteric pathogens, including Salmonella spp., and the emergence of inflammation-resistant (or antibiotic-resistant) microbiota via active horizontal gene transfer mediated by lytic bacteriophages.

Longitudinal evaluation of fecal microbiota transplantation for ameliorating calf diarrhea and improving growth performance.

Calf diarrhea is associated with enteric infections, and also provokes the overuse of antibiotics. Therefore, proper treatment of diarrhea represents a therapeutic challenge in livestock production and public health concerns. Here, we describe the ability of a fecal microbiota transplantation (FMT), to ameliorate diarrhea and restore gut microbial composition in 57 growing calves. We conduct multi-omics analysis of 450 longitudinally collected fecal samples and find that FMT-induced alterations in the gut microbiota (an increase in the family Porphyromonadaceae) and metabolomic profile (a reduction in fecal amino acid concentration) strongly correlate with the remission of diarrhea. During the continuous follow-up study over 24 months, we find that FMT improves the growth performance of the cattle. This first FMT trial in ruminants suggest that FMT is capable of ameliorating diarrhea in pre-weaning calves with alterations in their gut microbiota, and that FMT may have a potential role in the improvement of growth performance.

Leucobacter coleopterorum sp. nov., Leucobacter insecticola sp. nov., and Leucobacter viscericola sp. nov., isolated from the intestine of the diving beetles, Cybister brevis and Cybister lewisianus, and emended description of the genus Leucobacter.

Three novel bacterial strains, HDW9AT, HDW9BT, and HDW9CT, isolated from the intestine of the diving beetles Cybister lewisianus and Cybister brevis, were characterized as three novel species using a polyphasic approach. The isolates were Gram-staining-positive, strictly aerobic, non-motile, and rod-shaped. They grew optimally at 30°C (pH 7) in the presence of 0.5% (wt/vol) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that they belong to the genus Leucobacter and are closely related to L. denitrificans M1T8B10T (98.4-98.7% sequence similarity). Average nucleotide identity (ANI) values among the isolates were 76.4-84.1%. ANI values for the isolates and the closest taxonomic species, L. denitrificans KACC 14055T, were 72.3-73.1%. The isolates showed ANI values of < 76.5% with all analyzable Leucobacter strains in the EzBioCloud database. The genomic DNA G + C content of the isolates was 60.3-62.5%. The polar lipid components were phosphatidylglycerol, diphosphatidylglycerol, and other unidentified glycolipids, phospholipids, and lipids. The major cellular fatty acids were anteiso-C15:0, iso-C16:0, and anteiso-C17:0. MK-10 was the major respiratory quinone, and MK-7 and MK-11 were the minor respiratory quinones. The whole-cell sugar components of the isolates were ribose, glucose, galactose, and mannose. The isolates harbored L-2,4-diaminobutyric acid, L-serine, L-lysine, L-aspartic acid, glycine, and D-glutamic acid within the cell wall peptidoglycan. Based on phylogenetic, phenotypic, chemotaxonomic, and genotypic analyses, strains HDW9AT, HDW9BT, and HDW9CT represent three novel species within the genus Leucobacter. We propose the name Leucobacter coleopterorum sp. nov. for strain HDW9AT (= KACC 21331T = KCTC 49317T = JCM 33667T), the name Leucobacter insecticola sp. nov. for strain HDW9BT (= KACC 21332T = KCTC 49318T = JCM 33668T), and the name Leucobacter viscericola sp. nov. for strain HDW9CT (= KACC 21333T = KCTC 49319T = JCM 33669T).

Description of Vagococcus coleopterorum sp. nov., isolated from the intestine of the diving beetle, Cybister lewisianus, and Vagococcus hydrophili sp. nov., isolated from the intestine of the dark diving beetle, Hydrophilus acuminatus, and emended description of the genus Vagococcus.

A polyphasic taxonomic approach was used to characterize two novel bacterial strains, HDW17AT and HDW17BT, isolated from the intestine of the diving beetle Cybister lewisianus, and the dark diving beetle Hydrophilus acuminatus, respectively. Both strains were Gram-positive and facultative anaerobic cocci forming cream-colored colonies. The isolates grew optimally at 25°C, pH 7, in the presence of 0.3% (wt/vol) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences and genome sequences showed that the isolates were members of the genus Vagococcus, and strain HDW17AT was closely related to Vagococcus fessus CCUG 41755T (98.9% of 16S rRNA gene sequence similarity and 74.3% of average nucleotide identity [ANI]), whereas strain HDW17BT was closely related to Vagococcus fluvialis NCFB 2497T (98.9% of 16S rRNA gene sequence similarity and 76.6% of ANI). Both strains contained C16:0, and C18:1ω9c as the major cellular fatty acids, but C16:1ω9c was also observed only in strain HDW17BT as the major cellular fatty acid. The respiratory quinone of the isolates was MK-7. The major polar lipid components were phosphatidylglycerol, phosphatidylethanolamine, and diphosphatidylglycerol. The genomic DNA G + C content of strains HDW17AT and HDW17BT were 36.6 and 34.4%, respectively. Both strains had cell wall peptidoglycan composed of the amino acids L-alanine, glycine, D-glutamic acid, L-tryptophan, L-lysine, and L-aspartic acid, and the sugars ribose, glucose, and galactose. Based on phylogenetic, phenotypic, chemotaxonomic, and genotypic analyses, strains HDW17AT and HDW17BT represent two novel species in the genus Vagococcus. We propose the name Vagococcus coleopterorum sp. nov. for strain HDW17AT (= KACC 21348T = KCTC 49324T = JCM 33674T) and the name Vagococcus hydrophili sp. nov. for strain HDW17BT (= KACC 21349T = KCTC 49325T = JCM 33675T).

Male castration increases adiposity via small intestinal microbial alterations.

Castration of young males is widely used in the cattle industry to improve meat quality, but the mechanism linking hypogonadism and host metabolism is not clear. Here, we use metataxonomic and metabolomic approaches to evaluate the intestinal microbiota and host metabolism in male, castrated male (CtM), and female cattle. After pubescence, the CtM cattle harbor distinct ileal microbiota dominated by the family Peptostreptococcaceae and exhibit distinct serum and muscle amino acid profiles (i.e., highly abundant branched-chain amino acids), with increased extra- and intramuscular fat storage. We also evaluate the causative factor(s) that underpin the alteration of the intestinal microbiota and host metabolic phenotype in response to hypogonadism. Castration of male mice phenocopies both the intestinal microbial alterations and obese-prone metabolism observed in cattle. Antibiotic treatment and fecal microbiota transplantation experiments in a mouse model confirm that the intestinal microbial alterations associated with hypogonadism are a key contributor to the obese phenotype in the CtM animals. Collectively, targeting the gut microbiota is a potential therapeutic strategy for the treatment of both hypogonadism and obesity.