Effects of Bacteroides-Based Microecologics against Antibiotic-Associated Diarrhea in Mice

Polysaccharides of natural products alleviate antibiotic-associated diarrhea by regulating gut microbiota: a review

Antibiotic-associated diarrhea (AAD) is diarrhea caused by disturbances in intestinal microbiota and metabolism following inappropriate use of antibiotics. With the over-reliance on antibiotics, the incidence of AAD is increasing worldwide. Recently, the role of probiotics and prebiotic preparations in the prevention and treatment of AAD has received increasing attention. Various prebiotics can not only reduce the incidence of AAD, but also effectively shorten the course of the disease and alleviate the symptoms. Notably, many polysaccharides derived from plants and fungi are a class of biologically active and rich prebiotics with great potential to alleviate AAD. Therefore, this review aims to summarize the latest research on natural product polysaccharides to alleviate antibiotic-associated diarrhea by modulating the gut microbiota. It provides a theoretical basis for exploring the mechanism of natural product modulation of gut microbiota to alleviate AAD, and provides a reference for further development of active prebiotics.

Comprehensive evaluation of Flammulina velutipes residues polysaccharide based on in vitro digestion and human fecal fermentation

Flammulina velutipes residues (FVR) are the waste culture medium derived from the collection of Flammulina velutipes fruiting bodies, with an annual output that remains largely unexplored. The characteristics of digestion and fermentation of Flammulina velutipes residues polysaccharide (FVRP) are still relatively unknown. This study investigated the structure of the gut microbiota through 16 s rDNA gene sequencing and analyzed changes in short-chain fatty acid (SCFA) content via targeted metabolome analysis. The aim was to explore the prebiotic activity of FVRP based on a simulated digestion model combined with an in vitro anaerobic fermentation model. The results demonstrated that FVRP did not exhibit significant changes during in vitro digestion and fermentation but did enhance antioxidant activity. Furthermore, FVRP was found to rapidly reduce the pH value and increase SCFA production in the fermentation broth from lactic acid bacteria and human feces. Notably, FVRP altered the gut microbiota structure, significantly increasing the relative abundance of Firmicutes and Bacteroidota. Thus, FVRP could be considered a promising prebiotic food and feed additive that promotes the generation of short-chain fatty acids by modulating gut microbiota.

UPLC/Q-TOF-MS-based metabolomics and molecular docking analysis of Bifidobacterium adolescentis exposure to levofloxacin

Antibiotic-associated diarrhea is a common adverse reaction caused by the widespread use of antibiotics. The decrease in probiotics is one of the reasons why antibiotics cause drug-induced diarrhea. However, few studies have addressed the intrinsic mechanism of antibiotics inhibiting probiotics. To investigate the underlying mechanism of levofloxacin against Bifidobacterium adolescentis, we used a metabolomics mass spectrometry-based approach and molecular docking analysis for a levofloxacin-induced B. adolescentis injury model. The results showed that levofloxacin reduced the survival rate of B. adolescentis and decreased the number of B. adolescentis. The untargeted metabolomics analysis identified 27 potential biomarkers, and many of these metabolites are involved in energy metabolism, amino acid metabolism and the lipid metabolism pathway. Molecular docking showed that levofloxacin can bind with aminoacyl-tRNA synthetase and lactic acid dehydrogenase. This result provides a novel insight into the mechanism of the adverse reactions of levofloxacin.

Bifidobacterium adolescentis CCFM1285 combined with yeast β-glucan alleviates the gut microbiota and metabolic disturbances in mice with antibiotic-associated diarrhea

Antibiotic-associated diarrhea (AAD) is a self-limiting condition that can occur during antibiotic therapy. Our previous studies have found that a combination of Bacteroides uniformis and Bifidobacterium adolescentis can effectively alleviate AAD. However, the use of B. uniformis is still strictly limited. Therefore, this study attempted to use yeast β-glucan to enrich the abundance of B. uniformis in the intestine and supplement Bifidobacterium adolescentis to exert a synergistic effect. The lincomycin hydrochloride-induced AAD model was administered yeast β-glucan or a mixture of B. adolescentis CCFM1285 by gavage for one week. Subsequently, changes in the colonic histopathological structure, inflammatory factors, intestinal epithelial permeability and integrity, metabolites, and gut microbiota diversity were assessed. We found that yeast β-glucan, alone or in combination with B. adolescentis CCFM1285, can help attenuate systemic inflammation, increase the rate of tissue structural recovery, regulate metabolism, and restore the gut microbiota. Specifically, the combination of yeast β-glucan and B. adolescentis CCFM1285 was more effective in decreasing interleukin-6 levels, improving pathological changes in the colon, and upregulating occludin expression. Therefore, our study showed that the combination of yeast β-glucan and B. adolescentis CCFM1285 is an efficacious treatment for AAD.

Mannan-oligosaccharides promote gut microecological recovery after antibiotic disturbance

Antibiotic treatment often causes collateral damage to the gut microbiota, including changes in its diversity and composition. Dietary fiber helps maintain intestinal health, regulate short-chain fatty acids, and promote the recovery of the intestinal microbiome. However, it is currently unknown which specific plant-based dietary fiber is optimal as a dietary supplement for restoring the intestinal microbiota after antibiotic disturbance. Previously, we proposed predictive recovery-associated bacterial species (p-RABs) and identified the most important interventions. This study aimed to identify an optimal form of dietary fiber to recover the gut microbiome after antibiotic treatment. Therefore, we examined the types of dietary fibers associated with p-RABs through a p-RAB-metabolite bilayer network constructed from prior knowledge; we searched for dietary fiber that could provide nutritional support for Akkermansia muciniphila and Bacteroides uniformis. C57BL/6J mice were fed with 500 mg kg-1 of different types of dietary fibers daily for one week after being treated with ampicillin. The results showed that mannan-oligosaccharides could better promote the diversity of intestinal microbial growth, enhance the recovery of most genera, including Akkermansia and Bacteroides, and inhibit certain pathogenic bacteria, such as Proteus, compared to the other fiber types. Furthermore, mannan-oligosaccharides could regulate the levels of short-chain fatty acids, especially butyric acid. Functional predictions showed that starch metabolism, galactose metabolism, and the metabolism of other carbohydrates played key roles in the early recovery process. In conclusion, mannan-oligosaccharides could enhance the recovery of the intestinal microbiome after antibiotic treatment, offering valuable insights for targeted dietary strategies.

Review of yeast culture concerning the interactions between gut microbiota and young ruminant animals

Microorganisms inhabit the gastrointestinal tract of ruminants and regulate body metabolism by maintaining intestinal health. The state of gastrointestinal health is influenced not only by the macro-level factors of optimal development and the physiological structure integrity but also by the delicate equilibrium between the intestinal flora and immune status at the micro-level. Abrupt weaning in young ruminants causes incomplete development of the intestinal tract resulting in an unstable and unformed microbiota. Abrupt weaning also induced damages to the microecological homeostasis of the intestinal tract, resulting in the intestinal infections and diseases, such as diarrhea. Recently, nutritional and functional yeast culture has been researched to tackle these problems. Herein, we summarized current known interactions between intestinal microorganisms and the body of young ruminants, then we discussed the regulatory effects of using yeast culture as a feed supplement. Yeast culture is a microecological preparation that contains yeast, enriched with yeast metabolites and other nutrient-active components, including β-glucan, mannan, digestive enzymes, amino acids, minerals, vitamins, and some other unknown growth factors. It stimulates the proliferation of intestinal mucosal epithelial cells and the reproduction of intestinal microorganisms by providing special nutrient substrates to support the intestinal function. Additionally, the β-glucan and mannan effectively stimulate intestinal mucosal immunity, promote immune response, activate macrophages, and increase acid phosphatase levels, thereby improving the body's resistance to several disease. The incorporation of yeast culture into young ruminants' diet significantly alleviated the damage caused by weaning stress to the gastrointestinal tract which also acts an effective strategy to promote the balance of intestinal flora, development of intestinal tissue, and establishment of mucosal immune system. Our review provides a theoretical basis for the application of yeast culture in the diet of young ruminants.

Lasso peptide MccY alleviates non-typhoidal salmonellae-induced mouse gut inflammation via regulation of intestinal barrier function and gut microbiota

IMPORTANCE

Diseases caused by Enterobacteriaceae multidrug-resistant strains have become increasingly difficult to manage. It is necessary to verify the new antibacterial drug MccY effect on non-typhoid Salmonella infection in mice since it is regarded as a promising microcin. The results demonstrated that MccY has a potential therapeutic application value in the protection against Salmonella-induced intestinal damage and alleviating related intestinal dysbiosis and metabolic disorders. MccY could be a promising candidate as an antimicrobial or anti-inflammatory agent for treating infectious diseases.

Immunomodulatory Benefits of Probiotic Bacteria: A Review of Evidence

Over the past few decades, probiotics have emerged as a viable medical tool for preventing and/or treating diseases. This narrative review provides recent findings on Probiotics and their benefits on the host immune system. It also highlights the specific mechanisms through which probiotics mediate those benefits. The study also explores the topical or systemic probiotic administration method. Authors screened databases like Google Scholar, Web of Science, PubMed, Scopus, and China National Knowledge Infrastructure database, using various keyword combinations such as: “probiotic” AND “Immunomodulation” OR “probiotic” AND “Immunoregulation” OR “probiotic” AND “Immunostimulation”, for relevant literature written in English only. The review shows that probiotics can regulate the host immune system, including regulating T cells, dendritic cells, intestinal epithelial cells, and several signal pathways, and confer health benefits. Although several clinical trials also revealed the prospects and efficacy of probiotics as immunomodulators and treatment of diseases, there is a need for thorough future investigations on the effectiveness of specific strains of probiotics involved in immunomodulation.

The enhancement in toxic potency of oxidized functionalized polyethylene-microplastics in mice gut and Caco-2 cells

Microplastics (MPs) are inevitably oxidized in the environment, however, to date, no studies have discussed the biological toxicity of oxidized polyethylene (Ox-PE) MPs. In this study, oxidized low-density polyethylene (Ox-LDPE), a representative Ox-PE, was prepared using a selective oxidation method. The difference in toxicity between LDPE-MPs and Ox-LDPE-MPs were evaluated in C57BL/6 mice and Caco-2 cells. The proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FTIR) spectroscopy analyses revealed that some hydrocarbon-containing groups were transformed into carboxyl and ketone groups during selective oxidation. In vivo experiment results showed that LDPE-MPs and Ox-LDPE-MPs exists in the intestinal (duodenum and colon) of mice, and Ox-LDPE-MPs caused more severe intestinal histological changes, oxidative stress, and inflammatory response. The gut microbiota data showed that the relative abundance of Lactobacillus decreased significantly in the LDPE-MP- and Ox-LDPE-MP-exposed groups (P < 0.05). The predicted Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway suggested that exposure to LDPE-MPs or Ox-LDPE-MPs inhibited glycan biosynthesis and metabolism in the flora (P < 0.05). In vitro experiment results showed that selective oxidation to LDPE promoted its uptake by cells and aggravated adverse effects on cells, including reduced cell viability, damaged cell membrane, oxidative stress, and mitochondrial depolarization. The major mechanism of the increased toxicity of Ox-LDPE-MPs may be its easier accumulation and the ionic effect of oxygen-containing functional groups. Overall, these findings provide insights on the differences in toxicity between LDPE-MPs and Ox-LDPE-MPs. They also provide new perspectives for understanding the biohazards of MPs, which are necessary to accurately assess the potential environmental and health risks of these plastic pollutants.

Effects of systemic Bifidobacterium longum and Lactobacillus rhamnosus probiotics on the ligature-induced periodontitis in rat

Background/purpose

Probiotics might be beneficial in preventing periodontitis. Effects of Bifidobacterium and Lactobacillus on periodontitis were examined using the ligature-induced rat model.

Materials and methods

Thirty-five male Sprague-Dawley rats were divided into control, ligation, Bifidobacterium longum (BL986), Lactobacillus rhamnosus (LRH09), and combination groups. Periodontitis was induced in maxillary second molars. From the day before ligation, phosphate-buffered saline (for control and ligation groups) or probiotics (2 × 109 CFU/g for probiotic groups) were fed daily. On day 8, gingival mRNA expressions for interleukin (IL)-1β, IL-6, tissue necrosis factor (TNF)-α, IL-10, and NF-κB were determined via qPCR. Micro-computed tomography (μCT) and histomorphometry were employed to examine periodontal destruction.

Results

Compared to the ligation group, mRNA of IL-1β, TNF-α, IL-6, and NF-κB in probiotic groups were significantly decreased, but IL-10 was increased. Besides, the IL-10 was more significant in the combination group than in single-use group. Through μCT, the cementoenamel junction (CEJ)-to-bone distance and trabecular separation in combination group were less than that in ligation group, although the bone volume fraction and trabecular number/thickness showed an increase in three probiotic groups. Histopathologically, the combination group had significantly smaller gingival inflammatory cell-infiltrated area and CEJ-to-epithelium distance than the ligation group and the group with BL986 or LRH09. Additionally, the CEJ-to-bone distance was significantly smaller in the combination group than in the ligation and BL986 groups.

Conclusion

Systemic combination of BL986 and LRH09 had a synergistic effect on enhancing IL-10 and ameliorating the induced experimental periodontitis, although the single-use still presented partially alleviative effects.

Uncovering Predictive Factors and Interventions for Restoring Microecological Diversity after Antibiotic Disturbance

Antibiotic treatment can lead to a loss of diversity of gut microbiota and may adversely affect gut microbiota composition and host health. Previous studies have indicated that the recovery of gut microbes from antibiotic-induced disruption may be guided by specific microbial species. We expect to predict recovery or non-recovery using these crucial species or other indices after antibiotic treatment only when the gut microbiota changes. This study focused on this prediction problem using a novel ensemble learning framework to identify a set of common and reasonably predictive recovery-associated bacterial species (p-RABs), enabling us to predict the host microbiome recovery status under broad-spectrum antibiotic treatment. Our findings also propose other predictive indicators, suggesting that higher taxonomic and functional diversity may correlate with an increased likelihood of successful recovery. Furthermore, to explore the validity of p-RABs, we performed a metabolic support analysis and identified Akkermansia muciniphila and Bacteroides uniformis as potential key supporting species for reconstruction interventions. Experimental results from a C57BL/6J male mouse model demonstrated the effectiveness of p-RABs in facilitating intestinal microbial reconstitution. Thus, we proved the reliability of the new p-RABs and validated a practical intervention scheme for gut microbiota reconstruction under antibiotic disturbance.

Effect of water-soluble polysaccharides from Morchella esculenta on high-fat diet-induced obese mice: changes in gut microbiota and metabolic functions

Morchella esculenta polysaccharides exhibit numerous probiotic activities, but their regulatory effects on the gut microbiota are unclear. This study was conducted to explore whether M. esculenta polysaccharides can regulate dysbacteriosis caused by a high-fat diet and relieve obesity. We extracted a water-soluble polysaccharide from M. esculenta (MPF, purity: 96.19%, consisting of 55.97% glucose, 9.63% xylose, and 22% mannose) that reduces mouse fat accumulation, alleviates obesity, and relieves liver injury, after 90 days of high-fat diet intake. This polysaccharide reversed dysbiosis and regulated the abundance of gut microbiota caused by a high-fat diet (restoring the ratio of Firmicutes/Bacteroidetes and changing the abundances of Lactobacillus, Dubosiella, and Faecalibaculum), increasing short-chain fatty acids and decreasing gene expression in the liver (glucose 6-phosphatase, glucose transporter 1, peroxisome proliferator-activated receptor gamma (PPAR) receptor-1α, PPARα, PPARγ, and CCAAT enhancer binding protein α). We identified a regulatory relationship between polysaccharides, gut microbiota, and the liver as a potential mechanism by which polysaccharides can alleviate obesity.

Integrated microbiota and metabolite profiling analysis of prebiotic characteristics of Phellinus linteus polysaccharide in vitro fermentation

Phellinus linteus polysaccharide (PLP) had received increasing attention due to its multiple biological activities. Herein, the extraction, characterization and in vitro fermentation of PLP were studied to explore its physiochemical properties and the interaction mechanism between the gut microbiota and PLP. The results obtained demonstrated that PLP was mainly composed of 9 monosaccharides, with three gel chromatographic peaks and molecular weights (M_w) of 308.45 kDa, 13.58 kD and 3.33 kDa, respectively. After 48 h fermentation, the M_w, total sugar, reducing sugar, pH and monosaccharides composition were decreased. Furthermore, PLP regulated the composition of gut microbiota, such as promoting the proliferation of beneficial bacteria such as Bacteroides, Prevotella and Butyricimonas, while preventing the growth of pathogenic bacteria such as Escherichia-Shigella, Morganella and Intestinimonas. Gut microbiota metabolites regulated by PLP such as short-chain fatty acids were the main regulators that impact the host health. Bioinformatics analysis indicated that butyrate, bile acid and purine metabolism were the main metabolic pathways of PLP regulating host health, and the Bacteroides was the key genus to regulate these metabolic pathways. In conclusion, our finding suggested that PLP may be used as a prebiotic agent for human health because of its ability to regulate gut microbiota.

Metagenomics and metabolomics analysis to investigate the effect of Shugan decoction on intestinal microbiota in irritable bowel syndrome rats

BACKGROUND

The effect of Shugan Decoction (SGD) on intestinal motility and visceral hypersensitivity in Water avoid stress (WAS)-induced diarrhea predominant irritable bowel syndrome (IBS-D) model rats has been confirmed. However, the mechanisms of its action involved in the treatment of IBS-D need to be further studied. Intestinal microbiota plays an important role in maintaining intestinal homeostasis and normal physiological function. Changes in the intestinal microbiota and its metabolites are thought to participate in the pathophysiological process of IBS.

AIM

This study aimed to analyze the influence of SGD on intestinal microbiota and fecal metabolites in IBS-D rats by multiple omics techniques, including metagenomic sequencing and metabolomics.

METHODS

We measured the intestinal motility and visceral sensitivity of three groups of rats by fecal pellets output and colorectal distension (CRD) experiment. In addition, metagenome sequencing analysis was performed to explore the changes in the number and types of intestinal microbiota in IBS-D model rats after SGD treatment. Finally, we also used untargeted metabolomic sequencing to screen the metabolites and metabolic pathways closely related to the therapeutic effect of SGD.

RESULTS

We found that compared with the rats in the control group, the fecal pellets output of the rats in the WAS group increased and the visceral sensitivity threshold was decreased (P < 0.05). Compared with the rats in the WAS group, the fecal pellets output of the SGD group was significantly decreased, and the visceral sensitivity threshold increased (P < 0.05). Besides, compared with the rats in the WAS group, the relative abundance of Bacteroidetes increased in SGD group, while that of Firmicutes decreased at the phylum level, and at the species level, the relative abundance of Bacteroides sp. CAG:714, Lactobacillus reuteri and Bacteroides Barnesiae in SGD group increased, but that of bacterium D42-87 decreased. In addition, compared with the WAS group, several metabolic pathways were significantly changed in SGD group, including Taurine and hypotaurine metabolism, Purine metabolism, Sulfur metabolism, ABC transporters, Arginine and proline metabolism and Bile secretion.

CONCLUSION

SGD can regulate specific intestinal microbiota and some metabolic pathways, which may explain its effect of alleviating visceral hypersensitivity and abnormal intestinal motility in WAS-induced IBS-D rats.

Effects of sweeteners on host physiology by intestinal mucosal microbiota: Example-addition sweeteners in Qiweibaizhu Powder on intestinal mucosal microbiota of mice with antibiotic-associated diarrhea

In recent years, sweeteners have gained massive popularity under the trend of limiting sugar intake. Our previous study found that Qiweibaizhu Powder (QWBZP) could improve gut microbiota dysbiosis and has good efficacy in treating antibiotic-associated diarrhea (AAD). In this study, we investigated the effects of sucrose, sorbitol, xylitol, and saccharin on the intestinal mucosal microbiota of AAD mice treated with QWBZP. When the AAD model was constructed by being gavaged mixed antibiotic solution, Kunming mice were randomly assigned to seven groups: the control (mn) group, the ADD (mm) group, the QWBZP (mq) group, the saccharin + QWBZP (mc) group, the sucrose + QWBZP (ms) group, the xylito + QWBZP (mx) group, and the sorbitol + QWBZP (msl) group. Subsequently, 16S rRNA gene amplicon sequencing was used to analyze the intestinal mucosal microbiota composition and abundance. The results showed that feces from AAD mice were diluted and wet and improved diarrhea symptoms with QWBZP and sorbitol. In contrast, the addition of sucrose, saccharin, and xylitol delayed the healing of diarrhea. The relative abundance of intestinal mucosal microbiota showed Glutamicibacter, Robinsoniella, and Blautia were characteristic bacteria of the mx group, Candidatus Arthromitus, and Bacteroidales_S24-7_group as the typical bacteria of the mn group, Clostridium_innocuum_group as the distinct bacteria of the mm group. Mycoplasma and Bifidobacterium as the characteristic bacteria of the ms group. Correlation analysis of typical bacterial genera with metabolic functions shows that Blautia negatively correlates with D-Glutamine and D-glutamate metabolism. Bacteroidales_S24-7_group has a significant negative correlation with the Synthesis and degradation of ketone bodies. The study confirmed that sucrose, sorbitol, xylitol, and saccharin might further influence metabolic function by altering the intestinal mucosal microbiota. Compared to the other sweetener, adding sorbitol to QWBZP was the best therapeutic effect for AAD and increased the biosynthesis and degradation activities. It provides the experimental basis for applying artificial sweeteners in traditional Chinese medicine (TCM) as a reference for further rational development and safe use of artificial sweeteners.

Polystyrene nanoparticles aggravate the adverse effects of di-(2-ethylhexyl) phthalate on different segments of intestine in mice

Emerging evidence indicates that nanoplastics (NPs) can transport organic pollutants such as di-(2-ethylhexyl) phthalate (DEHP) into organisms and induce adverse health effects. Nevertheless, the toxic effects of NPs combined with DEHP on mammalian intestine are still unclear. In this study, the C57BL6J mice were exposed to polystyrene nanoparticles (PSNPs), DEHP or them both for 30 days to determine their effects on different segments of intestine and the gut microbiota. As a result, DEHP alone or co-exposure to DEHP and PSNPs induced histological damages in all intestinal parts, mainly manifested as the decreased villus lengths, increased crypt depths in the duodenum, jejunum and ileum and decreased villus counts accompanied with decreased epithelial area in the colon. Moreover, decreased mucus coverage, down-regulated Muc2 expression levels as well as the broken tight junctions were observed in intestinal epithelium of mice, particularly obvious in the co-treatment groups. In general, as manifested by greater alterations in most of the parameters mentioned above, simultaneously exposed to PSNPs and DEHP seemed to induce enhanced toxic effects on intestine of mouse when compared with DEHP alone. Furthermore, the altered community composition of gut microbiota might at least partially contribute to these abnormalities. Overall, our results highlight the aggravated toxicity on different segments of intestine in mammalians due to co-exposure of PSNPs and DEHP, and these findings will provide valuable insights into the health risk of NPs and plastic additives.