Fecal microbiota transfer for refractory intestinal graft-versus-host disease - Experience from two German tertiary centers.

RATIONALE: Steroid refractory graft-vs-host disease (sr-GvHD) represents a challenging complication after allogeneic hematopoietic cell transplantation (allo-HCT). Intestinal microbiota (IM) diversity and dysbiosis were identified as influencing factors for the development of acute GvHD. Fecal microbiota transfer (FMT) is hypothesized to restore IM dysbiosis, but there is limited knowledge about the significance of FMT in the treatment of sr-GvHD. OBJECTIVES: We studied the effects of FMT on sr-GvHD in allo-HCT patients from two German tertiary clinical centers (n = 11 patients; period: March 2017 until July 2019). To assess safety and clinical efficacy, we analyzed clinical data pre- and post-FMT (day -14 to +30 relative to FMT). Moreover, IM were analyzed in donor samples and in a subset of patients pre- and post-FMT by 16S rRNA sequencing. RESULTS: Post-FMT, we observed no intervention-associated, systemic inflammatory responses and only minor side effects (5/11 patients: abdominal pain and transformation of peristalsis-each 3/11 and vomiting-1/11). Stool frequencies and volumes were significantly reduced [pre- vs post-FMT (d14): P < .05, respectively] as well as clear attenuation regarding both grading and staging of sr-GvHD was present upon FMT. Moreover, IM analyses revealed an increase of alpha diversity as well as a compositional shifts toward the donor post-FMT. CONCLUSIONS: In our study, we observed positive effects on sr-GVHD after FMT without the occurrence of major adverse events. Although these findings are in line with published data on beneficial effects of FMT in sr-GvHD, further randomized clinical studies are urgently needed to better define the clinical validity including mode of action.

Vescimonas gen. nov., Vescimonas coprocola sp. nov., Vescimonas fastidiosa sp. nov., Pusillimonas gen. nov. and Pusillimonas faecalis sp. nov. isolated from human faeces.

Six strains of Gram-stain-negative, obligately anaerobic, non-spore-forming, non-motile rods were isolated from human faeces. Based on phylogenetic characteristics, the six isolates were included in the family Ruminococcaceae, and divided into three groups. The six isolates showed 16S rRNA gene sequence similarity values lower than 96.2 % to the closely related species, Oscillibacter ruminantium GH1T, Oscillibacter valericigenes Sjm18-20T and Dysosmobacter welbiomis J115T. Coherently with the 16S rRNA gene sequence results, the in silico DNA-DNA hybridization and average nucleotide identity values clearly indicated that strains MM35T, MM50T and MM59T belong to different species from the closely related three species. Based on phenotypic features and phylogenetic positions, three novel species, Vescimonas coprocola gen. nov., sp. nov., Vescimonas fastidiosa gen. nov., sp. nov. and Pusillimonas faecalis gen. nov., sp. nov. are proposed. The type strain of V. coprocola is strain MM50T (=JCM 34012T=DSM 111893T). The type strain of V. fastidiosa is strain MM35T (=JCM 34016T=DSM 111899T). The type strain of P. faecalis is strain MM59T (=JCM 34011T=DSM 111669T). The DNA G+C contents estimated according to the whole genomes of strains MM35T, MM50T and MM59T were 56.4, 58.2 and 55.2 mol%, respectively.

Blautia intestinalis sp. nov., isolated from human feces.

A strictly anaerobic bacterial strain (27-44T) was isolated from a stool specimen from an autistic child collected in PR China. The strain was Gram-stain-positive, non-motile, non-pigmented, non-spore-forming, and cells were oval to rod-shaped. Strain 27-44T grew at 20-40 °C (optimal at 37 °C) and at pH 6.0-10 (optimal at 6.0-8.0). The major polar lipids were one phospholipid, two glycolipids, two aminophospholipids and one unidentified lipid. The major cellular fatty acids of strain 27-44T were C16 : 0 and C17 : 0 2-OH. The end product of glucose fermentation was mainly butyric acid. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 27-44T was a member of the genus Blautia and phylogenetically closely related to Blautia obeum ATCC 29174T (with 97.8 % seque nce similarity). The genome of strain 27-44T was 3.5 Mbp with a DNA G+C content of 42.36 mol%. A total of 3436 genes were predicted and, of these, 3133 genes were annotated by KEGG. On the basis of phenotypic, chemotaxonomic and phylogenetic comparisons, strain 27-44T represents a novel species within the genus Blautia, for which the name Blautia intestinalis sp. nov. is proposed. The type strain is 27-44T= CGMCC 1.5285T=NBRC 113774T.

In vitro human intestinal microbiota biotransformation of nobiletin using liquid chromatography-mass spectrometry analysis and background subtraction strategy.

In this study, the in vitro biotransformation of nobiletin by human intestinal microbiota, which is a bioactive polymethoxyflavone widely presented in Citrus plants, has been investigated via utilizing an anaerobic incubation protocol. The incubation samples were detected using high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. A background subtraction strategy incorporated in Microsoft Office was employed to eliminate the interferences in medium and feces. The parent and three metabolites sinensetin, 5-hydroxy-6,7,3',4'-tetramethoxyflavone, and 5-demethylnobiletin were detected and identified based on the characteristics of their protonated molecules. The proposed metabolic pathway revealed that nobiletin went through phase I metabolism including demethylation and demethoxylation in human intestinal microbiota. The characterization of nobiletin metabolic profile transformed by human intestinal bacteria would be helpful for understanding its efficacy and action mechanism.

Dysosmobacter welbionis gen. nov., sp. nov., isolated from human faeces and emended description of the genus Oscillibacter.

A strictly anaerobic, Gram-stain-negative, non-spore-forming, non-motile, non-pigmented bacterium, strain J115T, was isolated from human faeces. Cells of strain J115T were straight rods, generally 1.8-3.0 µm, but could be up to 18 µm long. Growth occurred below 2 % (w/v) NaCl and 2 % (v/v) bile. Strain J115T produced acid from myo-inositol but not from d-glucose, d-ribose or d-xylose. Butyric acid was the major end-product from myo-inositol. The genomic DNA G+C content was 58.92 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the closest cultivated neighbours of strain J115T were Oscillibacter ruminantium GH1T (95.4 % similarity) and Oscillibacter valericigenes Sjm18-20T (94.1 %). Strain J115T was also related to the not-yet-cultured bacterium Oscillospira guilliermondii(92-93 % similarity). Coherently with the 16S rRNA gene sequence results, the ANI scores don't have units of strain J115T to O. ruminantium GH1T and O. valericigenes Sjm18-20T were 73.37 and 73.24, respectively, while in silico estimations of DNA-DNA hybridization were both 20.4 %, with confidence intervals of 18.2-22.9 % and 18.2-22.8 %, respectively. The major fatty acids were iso-C15 : 0 (24.2 %), C18 : 0 DMA (18.4 %), anteiso-C15 : 0 (15.2 %) and C16 : 0 DMA (7.6 %). No respiratory quinone was detected. Based on phenotypic features and phylogenetic position, it is proposed that this isolate represents a novel species in a new genus, Dysosmobacter welbionis gen. nov., sp. nov. The type strain of Dysosmobacter welbionis is J115T (DSM 106889T=LMG 30601T).

Butyricimonas faecalis sp. nov., isolated from human faeces and emended description of the genus Butyricimonas.

A Gram-negative, strictly anaerobic, non-spore forming, non-motile, non-pigmented bacterial strain, designated H184T, was isolated from human faeces. 16S rRNA gene sequence analysis showed that strain H184T represents a member of the genus Butyricimonas. Strain H184T is related to but distinct from Butyricimonasvirosa JCM 15149T and Butyricimonasparavirosa JCM 18677T, with 16S rRNA gene sequence similarities of 96.32 and 96.24 %, respectively. Strain H184T shared 90.50 % hsp60 gene sequence similarity to B. virosa JCM 15149T and B. paravirosa JCM 18677T. Growth occurs between 25 and 42 °C with an optimum at 37 °C. Bile and NaCl concentration range allowing growth are 0-3.75 % and 0-1.8 %, respectively. pH range for growth is 5.5-8. The strain produced propionate as the major end product from glucose. The major cellular fatty acids of strain H184T were iso-C15 : 0 (63.5 %) and iso-C17 : 0 3-OH (12.8%). The major menaquinone of the strain was MK-10 (86 %). DNA G+C content of the isolate H184T was 44.2 mol%. The genome-based comparison between strain H184T and B. virosa JCM 15149T by pairwise average nucleotide identity indicated a clear distinction with a score of 87.22. On the basis of these data, strain H184T represents a novel species of the genus Butyricimonas, for which the name Butyricimonas faecalis sp. nov. is proposed. The type strain of B. faecalis is H184T (DSM 106867T, LMG 30602T).

Parabacteroides acidifaciens sp. nov., isolated from human faeces.

A polyphasic taxonomic approach was applied to characterize an anaerobic bacterial strain, 426-9T, that was isolated from human faeces. The strain was Gram-stain-negative, non-motile, non-spore-forming, non-pigmented and rod-shaped. Strain 426-9T grew anaerobically at 20-45 °C (optimally at 37-40 °C) and at pH 6.0-10.0 (optimally at pH 6.0-8.0). The major polar lipids were phosphatidylethanolamine, seven amino phospholipids and three phospholipids. The major fatty acids of strain 426-9T were anteiso-C15 : 0 and iso-C17 : 0 3-OH, and the predominant respiratory quinones were menaquinones MK-9 and MK-10. End-products of glucose fermentation were acetate, propionate, iso-butyrate and iso-pentanoate. 16S rRNA gene sequence analysis showed that strain 426-9T was a member of the genus Parabacteroides. The level of 16S rRNA gene sequence similarity of strain 426-9T to the type species of the genus, Parabacteroides distasonis ATCC 8503T, was 91.0 %. Within the genus Parabacteroides, strain 426-9T was phylogenetically closely related to Parabacteroides johnsonii M-165T (96.0 % 16S rRNA gene sequence similarity). The draft genome of strain 426-9T comprised 5.15 Mb with a DNA G+C content of 45.9 mol%. A total of 4088 genes were predicted and, of those, 3744 were annotated. On the basis of phenotypic, chemotaxonomic and phylogenetic characterization, strain 426-9T represents a novel species within the genus Parabacteroides, for which the name Parabacteroides acidifaciens sp. nov. is proposed. The type strain is 426-9T (=CGMCC 1.13558T=NBRC 113433T).

The Clinical Link between Human Intestinal Microbiota and Systemic Cancer Therapy.

Clinical interest in the human intestinal microbiota has increased considerably. However, an overview of clinical studies investigating the link between the human intestinal microbiota and systemic cancer therapy is lacking. This systematic review summarizes all clinical studies describing the association between baseline intestinal microbiota and systemic cancer therapy outcome as well as therapy-related changes in intestinal microbiota composition. A systematic literature search was performed and provided 23 articles. There were strong indications for a close association between the intestinal microbiota and outcome of immunotherapy. Furthermore, the development of chemotherapy-induced infectious complications seemed to be associated with the baseline microbiota profile. Both chemotherapy and immunotherapy induced drastic changes in gut microbiota composition with possible consequences for treatment efficacy. Evidence in the field of hormonal therapy was very limited. Large heterogeneity concerning study design, study population, and methods used for analysis limited comparability and generalization of results. For the future, longitudinal studies investigating the predictive ability of baseline intestinal microbiota concerning treatment outcome and complications as well as the potential use of microbiota-modulating strategies in cancer patients are required. More knowledge in this field is likely to be of clinical benefit since modulation of the microbiota might support cancer therapy in the future.

Catenibacillus scindens gen. nov., sp. nov., a C-deglycosylating human intestinal representative of the Lachnospiraceae.

An anaerobic Gram-stain-positive, non-spore-forming and non-motile bacterium isolated from the human gut, designated CG19-1T, capable of cleaving aromatic C-glucosides was characterized using a polyphasic taxonomic approach. Major fermentation products of this asaccharolytic organism were acetate and butyrate when grown on a complex medium. Growth of strain CG19-1T was stimulated by glucose or pyruvate. Growth inhibition was observed in the presence of several phenolic acids including ferulic acid, which nevertheless was reduced to dihydroferulic acid. Strain CG19-1T contained peptidoglycan type A4ß l-Orn-d-Asp. The major cellular fatty acids were C16 : 0 and C18 : 1ω9c. The genomic DNA G+C content was 47.1 mol%. Based on its 16S rRNA gene sequence, strain CG19-1T is a member of the Lachnospiraceae. However, sequence identity to other Lachnospiraceae species with validly published names is approximately 93.0 % with Frisingicoccus caecimuris being the most closely related species according to phylogenetic analysis. Based on these findings, it is proposed to create a novel genus, Catenibacillus, and a novel species, Catenibacillus scindens, with the type strain CG19-1T (=DSM 106146T=CCUG 71490T).

Evaluation of inter-individual differences in gut bacterial isoflavone bioactivation in humans by PCR-based targeting of genes involved in equol formation.

AIM: To identify human subjects harbouring intestinal bacteria that bioactivate daidzein to equol using a targeted PCR-based approach. METHODS AND RESULTS: In a pilot study including 17 human subjects, equol formation was determined in faecal slurries. In parallel, faecal DNA was amplified by PCR using degenerate primers that target highly conserved regions of dihydrodaidzein reductase and tetrahydrodaidzein reductase genes. PCR products of the expected size were observed for six of the eight subjects identified as equol producers. Analysis of clone libraries revealed the amplification of sequences exclusively related to Adlercreutzia equolifaciens in four of the subjects tested positive for equol formation, whereas in three of the equol producers, only sequences related to Slackia isoflavoniconvertens were observed. No amplicons were obtained for one equol-forming subject, thus suggesting the presence of nontargeted alternative genes. Amplicons were only sporadically observed in the nonequol producers. CONCLUSION: The majority of human subjects who produced equol were also detected with the developed PCR-based approach. SIGNIFICANCE AND IMPACT OF THE STUDY: The obtained results shed light on the distribution and the diversity of known equol-forming bacterial species in the study group and indicate the presence of as yet unknown equol-forming bacteria.

Functional analysis of the type II toxin-antitoxin systems of the MazEF and RelBE families in Bifidobacterium longum subsp. infantis ATCC 15697.

Analysis of the Bifidobacterium longum subsp. infantis ATCC 15697 genome sequence for the presence of toxin-antitoxin genes revealed two relBE-like operons, three relB-mazF-like operons, one relB-vapC-like operon, one solitary gene coding for the MazF toxin and one gene coding for the RelB antitoxin. An attempt to clone the selected relE and mazF toxin genes from B. longum subsp. infantis ATCC 15697 revealed their toxic effects on Escherichia coli, which could be neutralized by coexpression of these toxins with their cognate antitoxins. The only two toxin proteins, RelE and VapC, that were found to be non-toxic to E. coli, were overproduced and purified. Electrophoretic assays showed that both RelE and VapC possessed direct endoribonuclease activity. The expression levels of toxin genes in B. longum subsp. infantis ATCC 15697 increased during the nutrient starvation and entry into the late stationary phase. The two relBE bicistronic operons relE2-relB1 and relE1-relB4 from B. longum subsp. infantis ATCC 15697 were cloned and overexpressed in B. longum subsp. longum NCC2705 strain. The strain B. longum NCC2705 [pCESH80::relE1-relB4] showed a significantly decreased growth rate with later onset of the log phase and decreased cells density in the stationary phase.

Long-term monitoring of the human intestinal microbiota from the 2nd week to 13 years of age.

Microbial contact begins prior to birth and continues rapidly thereafter. Few long term follow-up studies have been reported and we therefore characterized the development of intestinal microbiota of ten subjects from the 2nd week of life to 13 years of age. PCR-denaturing gradient gel electrophoresis combined with several bacterial group-specific primer sets demonstrated the colonization steps of defined bacterial groups in the microbiota. Bifidobacterium species were seen throughout the test period in all subjects. Bacteroides fragilis group and Blautia coccoides-Eubacterium rectale group species were not detected in several subjects during the first 6 months of life but were commonly seen after 12 months of life. Streptococcus group appeared during early life but was not seen in several subjects at the age of 13 years. Although a few species were linked with the increasing age, major bacterial species in the groups did not change dramatically. Rather considerable changes were found in the relative abundances of each bacterial species. Clustering analysis of total bacterial flora indicated that the microbiota changed considerably between 6 months and 12 months of life, and, at the age of 12 months, the intestinal microbiota was already converted toward a profile characteristic of an adult microbiota. Probiotic supplementation in the beginning of life did not have major impacts on later microbiota development.

QseC sensor kinase modulates the human microbiota during enterohemorrhagic Escherichia coli O157:H7 infection in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®).

Enterohemorrhagic Escherichia coli (EHEC) is an important gastrointestinal pathogen known for its ability to cause hemorrhagic colitis and induce hemolytic-uremic syndrome. The inner membrane QseC histidine kinase sensor has shown to be an important regulator of the locus of enterocyte effacement (LEE) island, where important EHEC key virulence genes are located. However, the QseC role during EHEC infection in human microbiota remains unknown. Herein, using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®), we investigated whether the QseC sensor has a role in human microbiota modulation by EHEC in a dynamic model. Our data demonstrated that the QseC sensor modulates human microbiota during EHEC infection, and its absence leads to an increase in Lactobacillaceae and Bifidobacterium genus predominance, although non-effect on Bacteroides genus by EHEC strains was observed. In co-culture, the Lactobacillus acidophilus has affected EHEC growth and impaired the EHEC growth under space-niche competition, although no growth difference was observed in the QseC sensor presence. Also, differences in EHEC growth were not detected in competition with Bacteroides thetaiotaomicron and EHEC strains did not affect B. thetaiotaomicron growth either. When investigating the mechanisms behind the SHIME results, we found that hcp-2 expression for the type 6 secretion system, known to be involved in bacterial competition, is under QseC sensor regulation beneath different environmental signals, such as glucose and butyrate. Our findings broaden the knowledge about the QseC sensor in modulating the human microbiota and its importance for EHEC pathogenesis.

Ultrasound Improved the Non-Covalent Interaction of ß-Lactoglobulin with Luteolin: Regulating Human Intestinal Microbiota and Conformational Epitopes Reduced Allergy Risks.

The present study aims to investigate the effects of ultrasound on the non-covalent interaction of ß-lactoglobulin (ß-LG) and luteolin (LUT) and to investigate the relationship between allergenicity and human intestinal microbiota. After treatment, the conformational structures of ß-LG were changed, which reflected by the decrease in α-helix content, intrinsic fluorescence intensity and surface hydrophobicity, whereas the ß-sheet content increased. Molecular docking studies revealed the non-covalent interaction of ß-LG and LUT by hydrogen bond, van der Walls bond and hydrophobic bond. ß-LG-LUT complex treated by ultrasound has a lower IgG/IgE binding ability and inhibits the allergic reaction of KU812 cells, depending on the changes in the conformational epitopes of ß-LG. Meanwhile, the ß-LG-LUT complex affected the composition of human intestinal microbiota, such as the relative abundance of Bifidobacterium and Prevotella. Therefore, ultrasound improved the non-covalent interaction of ß-LG with LUT, and the reduction in allergenicity of ß-LG depends on conformational epitopes and human intestinal microbiota changes.

MAIT cell activation is reduced by direct and microbiota-mediated exposure to bisphenols.

Oral uptake is the primary route of human bisphenol exposure, resulting in an exposure of the intestinal microbiota and intestine-associated immune cells. Therefore, we compared the impact of bisphenol A (BPA), bisphenol F (BPF) and bisphenol S (BPS) on (i) intestinal microbiota, (ii) microbiota-mediated immunomodulatory effects and (iii) direct effects on mucosal-associated invariant T (MAIT) cells in vitro. We acutely exposed human fecal microbiota, Bacteroides thetaiotaomicron and Escherichia coli to BPA and its analogues BPF and BPS referring to the European tolerable daily intake (TDI), i.e. 2.3 µg/mL, 28.3 µg/mL and 354.0 µg/mL. Growth and viability of E. coli was most susceptible to BPF, whereas B.thetaiotaomicron and fecal microbiota were affected by BPA > BPF > BPS. At 354.0 µg/mL bisphenols altered microbial diversity in compound-specific manner and modulated microbial metabolism, with BPA already acting on metabolism at 28.3 µg/mL. Microbiota-mediated effects on MAIT cells were observed for the individual bacteria at 354.0 µg/mL only. However, BPA and BPF directly modulated MAIT cell responses at low concentrations, whereby bisphenols at concentrations equivalent for the current TDI had no modulatory effects for microbiota or for MAIT cells. Our findings indicate that acute bisphenol exposure may alter microbial metabolism and impact directly on immune cells.

Bovine ß-Lactoglobulin Covalent Modification by Flavonoids: Effect on the Allergenicity and Human Intestinal Microbiota.

The present study aims to investigate the structure of covalent conjugates of bovine ß-lactoglobulin (BLG) and flavonoids (luteolin, myricetin, and hyperoside), and their effect on the allergenicity and human intestinal microbiota. Covalent modification of amino acids in BLG by flavonoids was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and o-phthaldialdehyde assay. The secondary and conformational structures of BLG were changed by the covalent modification, which were determined by the circular dichroism, Fourier transform infrared spectroscopy, fluorescence spectroscopy, and UV spectroscopy. The enzyme-linked immunosorbent assay (ELISA) and cell experiments indicated that BLG covalent conjugates could reduce IgE/IgG binding capacities and suppress the allergy reactivity of RBL-2H3 cells, suggesting that the covalent modification modulated the balance of T cells. Meanwhile, covalent modification of BLG with these flavonoids can alter the diversity of human intestinal microbiota and the community abundance at phylum, family, and genus levels. The results revealed that covalent modification of BLG with flavonoids alters human intestinal microbiota, might result in the reduction of allergenicity, which could provide information for confirming the relationship between food allergy and the intestinal microbial ecosystem.

Impact of Chronic Tetracycline Exposure on Human Intestinal Microbiota in a Continuous Flow Bioreactor Model.

Studying potential dietary exposure to antimicrobial drug residues via meat and dairy products is essential to ensure human health and consumer safety. When studying how antimicrobial residues in food impact the development of antimicrobial drug resistance and disrupt normal bacteria community structure in the intestine, there are diverse methodological challenges to overcome. In this study, traditional cultures and molecular analysis techniques were used to determine the effects of tetracycline at chronic subinhibitory exposure levels on human intestinal microbiota using an in vitro continuous flow bioreactor. Six bioreactor culture vessels containing human fecal suspensions were maintained at 37 °C for 7 days. After a steady state was achieved, the suspensions were dosed with 0, 0.015, 0.15, 1.5, 15, or 150 µg/mL tetracycline, respectively. Exposure to 150 µg/mL tetracycline resulted in a decrease of total anaerobic bacteria from 1.9 × 107 ± 0.3 × 107 down to 2 × 106 ± 0.8 × 106 CFU/mL. Dose-dependent effects of tetracycline were noted for perturbations of tetB and tetD gene expression and changes in acetate and propionate concentrations. Although no-observed-adverse-effect concentrations differed, depending on the traditional cultures and the molecular analysis techniques used, this in vitro continuous flow bioreactor study contributes to the knowledge base regarding the impact of chronic exposure of tetracycline on human intestinal microbiota.

Diet, Microbiome, and Cancer Immunotherapy-A Comprehensive Review.

The immune system plays a key role in cancer suppression. Immunotherapy is widely used as a treatment method in patients with various types of cancer. Immune checkpoint blockade using antibodies, such as anti-PD-1, anti-PD-L1, and anti-CTLA-4, is currently gaining popularity. A systematic literature search was executed, and all available data was summarized. This review shows that specific dietary patterns (such as, e.g., animal-based, vegetarian, or Mediterranean diet) alter the gut microbiome's composition. An appropriate intestinal microbiota structure might modulate the function of human immune system, which affects the bodily anti-cancer response. This paper shows also that specific bacteria species inhabiting the gastrointestinal tract can have a beneficial influence on the efficacy of immunotherapy. Antibiotics weaken gut bacteria and worsen the immune checkpoint blockers' efficacy, whereas a faecal microbiota transplant or probiotics supplementation may help restore bacterial balance in the intestine. Other factors (like vitamins, glucose, or BMI) change the cancer treatment response, as well. This review demonstrates that there is a strong association between one's diet, gut microbiome composition, and the outcome of immunotherapy. However, further investigation on this subject is required.

Mechanism of Reduction in Allergenicity and Altered Human Intestinal Microbiota of Digested ß-Lactoglobulin Modified by Ultrasonic Pretreatment Combined with Glycation.

The effects of ultrasound combined with glycation (UCG) on the allergenicity and human microbial community of ß-Lg during in vitro digestion were studied by ELISA, cell experiments, and 16S rRNA high-throughput sequencing. UCG modification and subsequent digestion significantly reduced allergenicity. The decrease in the allergenicity of ß-Lg depended not only on the low digestibility of glycated ß-Lg, which led to the decrease of some peptides with complete immunogenicity, but also the masking effect of glycation on allergen epitopes of ß-Lg. Meanwhile, UCG modification and subsequent digestion could alter the structures of intestinal microbiota and the community abundance at phylum, family, and genus levels, such as Bacteroidota, Fusobacteriota, Enterobacteriaceae, Bacteroidaceae, Ruminococcaceae, Bacteroides, and Faecalibacterium. These results show that simulated in vitro digestion of modified ß-Lg reduces allergenicity and alters human intestinal microbiota, which could provide a theoretical basis for studying the relationship between intestinal dysbiosis and cow's milk allergy.

Colistin and amoxicillin combinatorial exposure alters the human intestinal microbiota and antibiotic resistome in the simulated human intestinal microbiota.

Antibiotics treatment could cause the dysbiosis of human intestinal microbiota and antibiotic resistome. Fecal microbiota transplantation (FMT) has been an efficacious treatment to restore the dysbiosis of intestinal microbiota in a variety of intestinal diseases. However, to data, the effect of the combinatorial antibiotic treatment on microbiota, antibiotic resistome and the FMT for restoration affected by combinatorial antibiotic exposure in the human intestinal microbiota remain unclear. In this study, we systematically investigated the effect of the colistin and amoxicillin combinatorial exposure in the simulator of the human intestinal microbial ecosystem (SHIME) and found that this combinatorial exposure significantly altered (p < 0.05) the human intestinal microbiota and antibiotic resistome. The shift of bacterial community and antibiotic resistome could incompletely recovery to baseline by FMT treatment after combinatorial antibiotic exposure. Additionally, the variance of antibiotic resistome was dominantly driven by the bacterial community (41.18%-68.03%) after the combinatorial antibiotic exposure. Overall, this study first to investigate the influence of the colistin and amoxicillin combinatorial exposure on the intestinal microbiota and antibiotic resistome, and assess the FMT recovery in the simulated human intestinal microbiota, which may potentially provide a correct administration of antibiotics and application of FMT in the clinic.