High Intake of Sugar and the Balance between Pro- and Anti-Inflammatory Gut Bacteria

The so-called Western diet is rich in saturated fat and sugars and poor in plant-derived fibers, and it is associated with an increased risk of metabolic and cardiovascular diseases, as well as chronic (low grade) inflammation. The detrimental effects of poor diet are in part mediated by gut microbiota, whose composition, functionality and metabolic end products respond to dietary changes. Recent studies have shown that high intake of sugars increase the relative abundance of Proteobacteria in the gut, while simultaneously decreasing the abundance of Bacteroidetes, which can mitigate the effects of endotoxin, as well as reinforce gut barrier function. Thus, a high sugar intake may stagger the balance of microbiota to have increased pro-inflammatory properties and decreased the capacity to regulate epithelial integrity and mucosal immunity. Consequently, high dietary sugar can, through the modulation of microbiota, promote metabolic endotoxemia, systemic (low grade) inflammation and the development of metabolic dysregulation and thereby, high dietary sugar may have many-fold deleterious health effects, in addition to providing excess energy.Non peer reviewe

Modulation of Gut Microbiota for Health by Current and Next-Generation Probiotics

The human gut microbiota is a complex ecosystem and has an essential role in maintaining intestinal and systemic health. Microbiota dysbiosis is associated with a number of intestinal and systemic conditions and its modulation for human health is of great interest. Gut microbiota is a source of novel health-promoting bacteria, often termed as next-generation probiotics in order to distinguish them from traditional probiotics. The previous lessons learned with traditional probiotics can help the development of next-generation probiotics that target specific health issues and needs.Non peer reviewe

Molecular identification and characterisation of bifidobacteria and lactobacilli in the human gastrointestinal tract

Bifidobacteria and lactobacilli are considered to be members of the beneficial microbiota in the human gastrointestinal (GI) tract. The present study describes the development and validation of new molecular methods for the detection and analysis of bifidobacteria and lactobacilli and the application of new techniques to study Bifidobacterium and Lactobacillus populations in the human intestine. A method based on genus-specific PCR of 16S rDNA and denaturing gradient gel electrophoresis (DGGE) was developed and validated for profiling Bifidobacterium populations in human faeces. The PCR-DGGE method is a qualitative tool for assessing species/strain composition of complex communities by a single PCR reaction and subsequent resolution of the amplification products by DGGE in a sequence-dependent manner. The approach greatly facilitates the monitoring of faecal samples from large numbers of subjects to reveal bifidobacterial diversity and shifts occurring in it. The identification of DGGE fragments can be done by subsequent cloning and sequencing of the PCR products. Genotypic methods were developed and evaluated for the identification and characterisation of Lactobacillus casei -group lactobacilli ( L. casei, L. paracasei, L. rhamnosus , and L. zeae ). L. rhamnosus species-specific PCR was developed and validated. The discriminatory power of the three fingerprinting techniques, pulsed field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPD) and ribotyping, was compared. All three techniques were highly effective in differentiating strains below the species level and they can be placed in the following order with respect to their discriminatory power: PFGE > ribotyping > RAPD. Newly developed molecular methods were used to trace ingested probiotic strains L. rhamnosus GG (LGG) and B. lactis Bb12 in the GI-tract. The identity of LGG colonies was verified using a species-specific PCR and Bb12 was detected using the PCR-DGGE method. Both probiotic strains colonised the gut transiently and they were no longer detected in the faeces one week after the end of the administration in most subjects. The synbiotic approach with galactooligosaccharide (GOS) did not prolong the persistence of Bb12. Furthermore, LGG was found to attach in vivo to colonic mucosae and, although the attchment was temporary, to remain for more than a week after discontinuation of LGG administration. PCR-DGGE method was used to monitor qualitative changes in adult faecal Bifidobacterium populations in response to B. lactis Bb12 and/or GOS administration. In most subjects two weeks administration of Bb12 and/or GOS did not affect the qualitative composition of indigenous bifidobacterial populations, while Bb12 transiently colonised the gut. Qualitative molecular analysis was used to study the bacterial, bifidobacterial and lactobacilli populations in faeces of breast-fed and formula-fed infants before and after weaning. Genus and group-specific PCRs combined with DGGE and subsequent sequencing of the amplified 16S rDNA fragments revealed no difference in the prevalence or species distribution of Bifidobacterium and Lactobacillus between the two groups of infants. In general, DGGE patterns of 16S rDNA showed equal complexity of bacterial communities in breast-fed and formula-fed infants. Equally intensive changes occurred in the faecal microbiota in infants of both groups due to weaning.</p

Feasibility of Metatranscriptome Analysis from Infant Gut Microbiota: Adaptation to Solid Foods Results in Increased Activity of Firmicutes at Six Months

Peer reviewe

Genome Sequence of the Butyrate-Producing Anaerobic Bacterium Anaerostipes hadrus PEL 85

Peer reviewe

Cultivation and Genomics Prove Long-Term Colonization of Donor's Bifidobacteria in RecurrentClostridioides difficilePatients Treated With Fecal Microbiota Transplantation

Fecal microbiota transplantation (FMT) is an effective treatment for recurrentClostridioides difficileinfection (rCDI) and it's also considered for treating other indications. Metagenomic studies have indicated that commensal donor bacteria may colonize FMT recipients, but cultivation has not been employed to verify strain-level colonization. We combined molecular profiling ofBifidobacteriumpopulations with cultivation, molecular typing, and whole genome sequencing (WGS) to isolate and identify strains that were transferred from donors to recipients. SeveralBifidobacteriumstrains from two donors were recovered from 13 recipients during the 1-year follow-up period after FMT. The strain identities were confirmed by WGS and comparative genomics. Our results show that specific donor-derived bifidobacteria can colonize rCDI patients for at least 1 year, and thus FMT may have long-term consequences for the recipient's microbiota and health. Conceptually, we demonstrate that FMT trials combined with microbial profiling can be used as a platform for discovering and isolating commensal strains with proven colonization capacity for potential therapeutic use.Peer reviewe

The Potential of Gut Commensals in Reinforcing Intestinal Barrier Function and Alleviating Inflammation

The intestinal microbiota, composed of pro- and anti-inflammatory microbes, has an essential role in maintaining gut homeostasis and functionality. An overly hygienic lifestyle, consumption of processed and fiber-poor foods, or antibiotics are major factors modulating the microbiota and possibly leading to longstanding dysbiosis. Dysbiotic microbiota is characterized to have altered composition, reduced diversity and stability, as well as increased levels of lipopolysaccharide-containing, proinflammatory bacteria. Specific commensal species as novel probiotics, so-called next-generation probiotics, could restore the intestinal health by means of attenuating inflammation and strengthening the epithelial barrier. In this review we summarize the latest findings considering the beneficial effects of the promising commensals across all major intestinal phyla. These include the already well-known bifidobacteria, which use extracellular structures or secreted substances to promote intestinal health. Faecalibacterium prausnitzii, Roseburia intestinalis, and Eubacterium hallii metabolize dietary fibers as major short-chain fatty acid producers providing energy sources for enterocytes and achieving anti-inflammatory effects in the gut. Akkermansia muciniphila exerts beneficial action in metabolic diseases and fortifies the barrier function. The health-promoting effects of Bacteroides species are relatively recently discovered with the findings of excreted immunomodulatory molecules. These promising, unconventional probiotics could be a part of biotherapeutic strategies in the future.Peer reviewe

Development of a Time-Dependent Oral Colon Delivery System of Anaerobic Odoribacter splanchnicus for Bacteriotherapy

Odoribacter (O.) splanchnicus is an anaerobic member of the human intestinal microbiota. Its decrease in abundance has been associated with inflammatory bowel disease (IBD), non-alcoholic fatty liver, and cystic fibrosis. Considering the anti-inflammatory properties of O. splanchnicus and its possible use for IBD, intestinal isolate O. splanchnicus 57 was here formulated for oral colonic release based on a time-dependent strategy. Freeze-drying protocol was determined to ensure O. splanchnicus 57 viability during the process. Disintegrating tablets, containing the freeze-dried O. splanchnicus 57, were manufactured by direct compression and coated by powder-layering technique with hydroxypropyl methylcellulose (Methocel™ E50) in a tangential-spray fluid bed. Eudragit® L was then applied by spray-coating in a top-spray fluid bed. Double-coated tablets were tested for release, showing gastric resistance properties and, as desired, lag phases of reproducible duration prior to release in phosphate buffer pH 6.8. The cell viability and anti-inflammatory activity of the strain were assessed after the main manufacturing steps. While freeze-drying did not affect bacterial viability, the tableting and coating processes were more stressful. Nonetheless, O. splanchnicus 57 cells survived manufacturing and the final formulations had 106-107 CFU/g of viable cells. The strain kept its anti-inflammatory properties after tableting and coating, reducing Escherichia coli lipopolysaccharide-induced interleukin-8 cytokine release from HT-29 cells. Overall, O. splanchnicus 57 strain was formulated successfully for oral colon delivery, opening new ways to formulate pure cultures of single anaerobic strains or mixtures for oral delivery