The effect of Lactobacillus brevis KB290 against irritable bowel syndrome: a placebo-controlled double-blind crossover trial

Dietary Effects on the Gut Phageome

As knowledge of the gut microbiome has expanded our understanding of the symbiotic and dysbiotic relationships between the human host and its microbial constituents, the influence of gastrointestinal (GI) microbes both locally and beyond the intestine has become evident. Shifts in bacterial populations have now been associated with several conditions including Crohn's disease (CD), Ulcerative Colitis (UC), irritable bowel syndrome (IBS), Alzheimer's disease, Parkinson's Disease, liver diseases, obesity, metabolic syndrome, anxiety, depression, and cancers. As the bacteria in our gut thrive on the food we eat, diet plays a critical role in the functional aspects of our gut microbiome, influencing not only health but also the development of disease. While the bacterial microbiome in the context of disease is well studied, the associated gut phageome-bacteriophages living amongst and within our bacterial microbiome-is less well understood. With growing evidence that fluctuations in the phageome also correlate with dysbiosis, how diet influences this population needs to be better understood. This review surveys the current understanding of the effects of diet on the gut phageome.

Probiotics for the management of irritable bowel syndrome: a systematic review and three-level meta-analysis

OBJECTIVE

Previous systematic reviews demonstrated a potentially beneficial effect of probiotics on irritable bowel syndrome (IBS). However, these studies are either affected by the inclusion of insufficient trials or by the problem of dependent data across multiple outcomes, and an overall effect size has not been provided. We aimed to determine the effect of probiotics on IBS through a three-level meta-analysis and clarify potential effect moderators.

METHODS

We searched MEDLINE, Embase, and Web of Science, screening for randomized controlled trials (RCTs) that examine the effect of probiotics on IBS. The primary outcome was the improvement in the severity of global IBS symptoms at the end of treatment. The secondary outcomes were the improvement in abdominal pain and the quality of life. The effect sizes of the probiotics were measured by using the standardized mean difference (SMD) and pooled by a three-level meta-analysis model.

RESULTS

We included 72 RCTs in the analysis. The meta-analysis showed significantly better overall effect of probiotics than placebo on the global IBS symptoms (SMD -0.55, 95% CI -0.76 to -0.34, P <0.001), abdominal pain (SMD -0.89, 95% CI -1.29 to -0.5, P <0.001) and quality of life (SMD 0.99, 95% CI 0.45 to 1.54, P <0.001), respectively. Moderator analysis found that a treatment duration shorter than 4 weeks was associated with a larger effect size in all the outcomes, and Bacillus probiotics had better improvement on the abdominal pain.

CONCLUSIONS

Probiotics had a short-term effect and a medium effect size on the global IBS symptoms. Treatment duration and types of probiotics affected the effect size of probiotics, and shorter durations and Bacillus probiotics were associated with better treatment effects.

REGISTRATION

Open Science Framework.

Could the Microbiota Be a Predictive Factor for the Clinical Response to Probiotic Supplementation in IBS-D? A Cohort Study

BACKGROUND

Increasing evidence suggests the beneficial effects of probiotics in irritable bowel syndrome (IBS), but little is known about how they can impact the gut microbiota. Our objective was to evaluate the effects of a multistrain probiotic on IBS symptoms, gut permeability and gut microbiota in patients with diarrhoea-predominant IBS (IBS-D).

METHODS

Adults with IBS-D were enrolled in an open-label trial to receive a multistrain probiotic for 4 weeks. Abdominal pain, stool frequency, quality of life, gut permeability, and the luminal and adherent microbiota from colonic biopsies were evaluated before and after supplementation.

RESULTS

Probiotics significantly improved symptoms and quality of life, despite having no impact on permeability in the global population. In the population stratified by the response, the diarrhoea responders displayed reduced colonic permeability after supplementation. The luminal and adherent microbiota were specifically altered depending on the patients' clinical responses regarding pain and diarrhoea. Interestingly, we identified a microbial signature in IBS-D patients that could predict a response or lack of response to supplementation.

CONCLUSIONS

The multistrain probiotic improved the symptoms of IBS-D patients and induced distinct effects on the gut microbiota according to the patient's clinical response and initial microbiota composition. Our study further supports the need to develop individualised probiotic-based approaches regarding IBS.

Lactobacillus gasseri LA806 Supplementation in Patients with Irritable Bowel Syndrome: A Multicenter Study

The potential benefits of Lactobacillus gasseri LA806 in IBS were previously identified in a comprehensive preclinical research program. The purpose of this multicenter study was to explore in real-life conditions changes in IBS symptoms and quality of life in patients receiving a 4-week supplementation with L. gasseri LA806. Altogether 119 patients meeting Rome IV criteria for IBS were included, of whom 118 received the supplement. The majority of patients (71.8% (95% CI 63.6−79.9%)) manifested a ≥30% decrease in abdominal pain at 4 weeks, the mean abdominal pain score diminishing by 54.2% (from 5.3 ± 2.2 to 2.2 ± 2.4, p < 0.0001). A statistically significant decrease in abdominal pain was seen as early as the first week. A decrease of ≥30% in both abdominal pain score and global IBS symptom score was attained in 61.5% of patients (95% CI 51.7−71.2%). The mean IBS-SSS score fell by 152 ± 112 points (p = 0.001), with symptoms being attenuated in 85% of patients (CGI-I). Supplementation led to a 10-fold decrease in the number of patients reporting severe IBS symptoms. The concomitant intake of antidiarrheals, antispasmodics and analgesics decreased and quality of life scores significantly improved. These preliminary results warrant confirmation by a randomized, placebo-controlled study that this study will allow a better design.

Gut Non-Bacterial Microbiota: Emerging Link to Irritable Bowel Syndrome

As a common functional gastrointestinal disorder, irritable bowel syndrome (IBS) significantly affects personal health and imposes a substantial economic burden on society, but the current understanding of its occurrence and treatment is still inadequate. Emerging evidence suggests that IBS is associated with gut microbial dysbiosis, but most studies focus on the bacteria and neglect other communities of the microbiota, including fungi, viruses, archaea, and other parasitic microorganisms. This review summarizes the latest findings that link the nonbacterial microbiota with IBS. IBS patients show less fungal and viral diversity but some alterations in mycobiome, virome, and archaeome, such as an increased abundance of Candida albicans. Moreover, fungi and methanogens can aid in diagnosis. Fungi are related to distinct IBS symptoms and induce immune responses, intestinal barrier disruption, and visceral hypersensitivity via specific receptors, cells, and metabolites. Novel therapeutic methods for IBS include fungicides, inhibitors targeting fungal pathogenic pathways, probiotic fungi, prebiotics, and fecal microbiota transplantation. Additionally, viruses, methanogens, and parasitic microorganisms are also involved in the pathophysiology and treatment. Therefore, the gut nonbacterial microbiota is involved in the pathogenesis of IBS, which provides a novel perspective on the noninvasive diagnosis and precise treatment of this disease.

Modulating the gut microenvironment as a treatment strategy for irritable bowel syndrome: a narrative review

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction with a complex pathophysiology. Growing evidence suggests that alterations of the gut microenvironment, including microbiota composition and function, may be involved in symptom generation. Therefore, attempts to modulate the gut microenvironment have provided promising results as an indirect approach for IBS management. Antibiotics, probiotics, prebiotics, food and faecal microbiota transplantation are the main strategies for alleviating IBS symptom severity by modulating gut microbiota composition and function (eg. metabolism), gut barrier integrity and immune activity, although with varying efficacy. In this narrative review, we aim to provide an overview of the current approaches targeting the gut microenvironment in order to indirectly manage IBS symptoms.

Low FODMAP Diet and Probiotics in Irritable Bowel Syndrome: A Systematic Review With Network Meta-analysis

Background: Probiotic and low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet are two commonly used management approaches for patients with irritable bowel syndrome (IBS). We aimed to evaluate the most effective combinations and components among different probiotics or low FODMAP diet through component network meta-analysis (NMA).

Methods: We searched Embase, Ovid Medline, and Web of Science from inception to 21 January 2021. Randomized controlled trials (RCTs) examining the efficacy of probiotics and low FODMAP diet for IBS were included, with placebo, sham diet, or conventional treatments as controls. Binary outcomes were compared among treatments using the relative ratio (RR). A minimally contextualized framework recommended by the GRADE group was used to evaluate the certainty of evidence. The primary efficacy outcome was the relief of global IBS symptoms, and the secondary efficacy outcome was the reduction in IBS symptom scores or abdominal pain scores.

Key Results: We included 76 RCTs (n = 8058) after screening 1940 articles. Eight RCTs were classified as low risk of bias. Standard network meta-analysis (NMA) showed that Lactobacillus (RR 1.74, 95% CI 1.22–2.48) and Bifidobacterium (RR 1.76, 95% CI 1.01–3.07) were the most effective for the primary efficacy outcome (high certainty evidence); component NMA showed that Bacillus (RR 5.67, 95% CI 1.88 to 17.08, p = 0.002) and Lactobacillus (RR 1.42, 95% CI 1.07 to 1.91, p = 0.017) were among the most effective components. The results of standard NMA and CNMA analysis of the improvement of overall IBS symptom scores or abdominal pain scores were consistent with this finding.

Conclusion:Lactobacillus was the most effective component for the relief of IBS symptoms; Bifidobacterium and Bacillus were possibly effective and need further verification.

Systematic Review Registration: website, identifier registration number.

Probiotics, prebiotics and synbiotics: Safe options for next-generation therapeutics

Probiotics have been considered as an economical and safe alternative for the treatment of a large number of chronic diseases and improvement of human health. They are known to modulate the host immunity and protect from several infectious and non-infectious diseases. The colonization, killing of pathogens and induction of host cells are few of the important probiotic attributes which affect several functions of the host. In addition, prebiotics and non-digestible food substances selectively promote the growth of probiotics and human health through nutrient enrichment, and modulation of gut microbiota and immune system. This review highlights the role of probiotics and prebiotics alone and in combination (synbiotics) in the modulation of immune system, treatment of infections, management of inflammatory bowel disease and cancer therapy. KEY POINTS: • Probiotics and their derivatives against several human diseases. • Prebiotics feed probiotics and induce several functions in the host. • Discovery of novel and biosafe products needs attention for human health.

Multi-Omics Analyses Show Disease, Diet, and Transcriptome Interactions With the Virome

BACKGROUND & AIMS

The gut virome includes eukaryotic viruses and bacteriophages that can shape the gut bacterial community and elicit host responses. The virome can be implicated in diseases, such as irritable bowel syndrome (IBS), where gut bacteria play an important role in pathogenesis. We provide a comprehensive and longitudinal characterization of the virome, including DNA and RNA viruses and paired multi-omics data in a cohort of healthy subjects and patients with IBS.

METHODS

We selected 2 consecutive stool samples per subject from a longitudinal study cohort and performed metagenomic sequencing on DNA and RNA viruses after enriching for viral-like particles. Viral sequence abundance was evaluated over time, as well as in the context of diet, bacterial composition and function, metabolite levels, colonic gene expression, host genetics, and IBS subsets.

RESULTS

We found that the gut virome was temporally stable and correlated with the colonic transcriptome. We identified IBS-subset-specific changes in phage populations; Microviridae, Myoviridae, and Podoviridae species were elevated in diarrhea-predominant IBS, and other Microviridae and Myoviridae species were elevated in constipation-predominant IBS compared to healthy controls. We identified correlations between subsets of the virome and bacterial composition (unclassifiable "dark matter" and phages) and diet (eukaryotic viruses).

CONCLUSIONS

We found that the gut virome is stable over time but varies among subsets of patients with IBS. It can be affected by diet and potentially influences host function via interactions with gut bacteria and/or altering host gene expression.

Probiotics, Prebiotics, and Synbiotics in the Irritable Bowel Syndrome Treatment: A Review

Irritable bowel syndrome is not a life-threatening disease, yet it significantly affects the quality of life and contributes to economic loss. It is estimated that even up to 45% of the world's population can suffer from the disease. The first attempts to diagnose irritable bowel syndrome were made at the end of the 19th century; however, establishing appropriate diagnostic criteria and treatment methods is still ongoing. To date, little is known about the etiology of irritable bowel syndrome; however, growing attention is drawn to the intestinal microbiota as a factor in the disease development. For this reason, researchers have conducted many studies on therapies that modulate the microbiota, among which probiotics, prebiotics, and synbiotics are widely studied. To date, most studies have examined probiotics; however, there are also several studies demonstrating the efficacy of prebiotics and synbiotics. The aim of this review was to summarize findings on the usefulness of probiotics, prebiotics, and synbiotics in the treatment of irritable bowel syndrome.

Non-Celiac Gluten Sensitivity and Irritable Bowel Disease: Looking for the Culprits

During the last 30 y, a gluten-free diet has been classified among the most popular fad diets mainly due to the ambiguous notion that gluten avoidance promotes health. Gluten intolerance has been implicated in non-celiac gluten sensitivity (NCGS) and irritable bowel syndrome (IBS), 2 disorders with overlapping symptoms and increasing trend. Together with gluten, other wheat components; fermentable oligo-, di-, monosaccharide, and polyols (FODMAPs); and amylase trypsin inhibitors (ATIs), are implicated in the pathogenesis of both disorders. Gut microflora alterations in IBS and NCGS have been described, while microbiota manipulations have been shown to be promising in some IBS cases. This literature review summarizes our current knowledge on the impact of wheat ingredients (gluten, FODMAPs, and ATIs) in IBS and NCGS. In both disorders, FODMAPs and ATIs trigger gut dysbiosis, suggesting that gluten may not be the culprit, and microbiota manipulations can be applied in diagnostic and intervention approaches.

Microbiota Stability and Gastrointestinal Tolerance in Response to a High-Protein Diet with and without a Prebiotic, Probiotic, and Synbiotic: A Randomized, Double-Blind, Placebo-Controlled Trial in Older Women

BACKGROUND

Higher protein intakes may help reduce sarcopenia and facilitate recovery from illness and injury in older adults. However, high-protein diets (HPDs) including animal-sourced foods may negatively perturb the microbiota, and provision of probiotics and prebiotics may mitigate these effects.

OBJECTIVE

The aim of this study was to examine the effects of HPD, with and without a probiotic and/or prebiotic, on gut microbiota and wellness in older women.

DESIGN

We conducted an 18-week, double-blind, placebo-controlled, crossover study.

PARTICIPANTS/SETTING

Participants were healthy, older women (mean age±standard deviation=73.7±5.6 years; n=26) recruited from Florida.

INTERVENTION

Participants received a weight-maintenance HPD for 2-week periods and the following, in random order: HPD alone (1.5 to 2.2 g/kg/day protein); HPD plus multistrain probiotic formulation (1.54×10⁹Bifidobacterium bifidum HA-132, 4.62×10⁹Bifidobacterium breve HA-129, 4.62×10⁹Bifidobacterium longum HA-135, 4.62×10⁹Lactobacillus acidophilus HA-122, and 4.62×10⁹Lactobacillus plantarum HA-119), HPD plus prebiotic (5.6 g inulin), and HPD plus synbiotic (probiotic plus inulin), separated by 2-week washouts. Stools were collected per period for quantitative polymerase chain reaction (strain recovery) and 16S ribosomal RNA gene amplicon sequencing analyses (microbiota profile). Measures of gastrointestinal and general wellness were assessed.

MAIN OUTCOME MEASURES

Microbiota composition and probiotic strain recovery were measured.

STATISTICAL ANALYSES

Microbiota composition was analyzed by Wilcoxon signed-rank test and t test. Secondary outcomes were analyzing using generalized linear mixed models.

RESULTS

The microbiota profile demonstrated relative stability with the HPD; representation of Lactobacillus, Lactococcus, and Streptococcus were enhanced, whereas butyrate producers, Roseburia and Anaerostipes, were suppressed. Lactococcus was suppressed with synbiotic vs other HPD periods. Recovery was confirmed for all probiotic strains. Indicators of wellness were unchanged, with the exception of a minimal increase in gastrointestinal distress with inulin. Fat-free mass increased from baseline to study end.

CONCLUSIONS

An HPD adhering to the recommended acceptable macronutrient distribution ranges maintains wellness in healthy older women and exerts minor perturbations to the microbiome profile, a group that may benefit from a higher protein intake. ClinicalTrials.gov ID: NCT #02445560.

Short Communication: Oral Administration of Heat-killed Lactobacillus brevis KB290 in Combination with Retinoic Acid Provides Protection against Influenza Virus Infection in Mice

Influenza virus type A (IAV) is a seasonal acute respiratory disease virus with severe symptoms, and an effective preventive measure is required. Despite many reports describing the potentially protective effects of lactic acid bacteria, few studies have investigated the effects of nutritional supplement combinations. This study reports the effect of the combined intake of heat-killed Lactobacillus brevis KB290 (KB290) and vitamin A (VA) on mice challenged with a sublethal dose of IAV. For 2 weeks, five groups of mice were fed either placebo, KB290, VA, or a combination of KB290 and VA (KB290+VA). After subsequent IAV challenge, bodyweight and general health were monitored for up to 2 weeks. Viral titres were determined in the lungs of animal subgroups euthanised at days 3, 7, and 14 after IAV challenge. A significant loss was observed in the bodyweights of IAV-infected animals from day 1 post-IAV challenge, whereas the mice fed KB290+VA did not lose any weight after IAV infection, indicating successful protection from the infection. Additionally, mice in the KB290+VA group showed the highest reduction in lung viral titres. In conclusion, the combination of KB290 and VA could be a useful food supplement relevant for protection against seasonal influenza virus infection in humans.

Lactobacillus brevis CD2: Fermentation Strategies and Extracellular Metabolites Characterization

Functional foods and nutraceuticals frequently contain viable probiotic strains that, at certain titers, are considered to be responsible of beneficial effects on health. Recently, it was observed that secreted metabolites might play a key role in this respect, especially in immunomodulation. Exopolysaccharides produced by probiotics, for example, are used in the food, pharmaceutical, and biomedical fields, due to their unique properties. Lactobacillus brevis CD2 demonstrated the ability to inhibit oral pathogens causing mucositis and periodontal inflammation and to reduce Helycobacter pylori infections. Due to the lack of literature, for this strain, on the development of fermentation processes that can increase the titer of viable cells and associated metabolites to industrially attractive levels, different batch and fed-batch strategies were investigated in the present study. In particular, aeration was shown to improve the growth rate and the yields of lactic acid and biomass in batch cultures. The use of an exponential feeding profile in fed-batch experiments allowed to produce 9.3 ± 0.45 × 10⁹ CFU/mL in 42 h of growth, corresponding to a 20-fold increase of viable cells compared with that obtained in aerated batch processes; moreover, also increased titers of exopolysaccharides and lactic acid (260 and 150%, respectively) were observed. A purification process based on ultrafiltration, charcoal treatment, and solvent precipitation was applied to partially purify secreted metabolites and separate them into two molecular weight fractions (above and below 10 kDa). Both fractions inhibited growth of the known gut pathogen, Salmonella typhimurium, demonstrating that lactic acid plays a major role in pathogen growth inhibition, which is however further enhanced by the presence of Lact. brevis CD2 exopolysaccharides. Finally, the EPS produced from Lact. brevis CD2 was characterized by NMR for the first time up to date.

Relation between cell-bound exopolysaccharide production via plasmid-encoded genes and rugose colony morphology in the probiotic Lactobacillus brevis KB290

The probiotic Lactobacillus brevis KB290 is a natural producer of cell-bound exopolysaccharide (EPS), and the plasmid-encoded glycosyltransferase genes are responsible for this EPS production. KB290 forms unique rugose colonies inside an agar medium; this characteristic is useful for detecting and enumerating KB290 in the gut or feces. However, the genetic elements associated with this morphology remain unclear. Here, we aimed to investigate the relation between the plasmid eps genes and rugose colony morphology in KB290. The plasmid-cured mutants formed smooth colonies, and the rugose colony morphology was restored after complementation with the eps genes. The eps genes were successfully cloned and expressed in other L. brevis and L. plantarum strains. In these transformant strains, the presence of the EPS, consisting of glucose and N-acetylglucosamine, correlated with rugose colonies, indicating that EPS is responsible for rugose colony formation. To the best of our knowledge, this is the first report identifying the genetic factors influencing rugose colonies in Lactobacillus strains. This rugose colony formation may serve as a useful selective marker for KB290 in routine laboratory and research settings and can be used to detect the spontaneous loss of plasmids in this strain.

Antilisterial efficacy of Lactobacillus brevis MF179529 from cow: an in vivo evidence

Background

Listeria monocytogenes is an opportunistic foodborne pathogen that causes human Listeriosis and high mortality particularly in immunocompromised individuals. Pregnant women are more prone to L. monocytogenes infection resulting in abortions.

In the present study, antilisterial activity of Lactobacillus brevis (LB) MF179529, a probiotic bacterial strain, was investigated in a murine model.

Methods

Initially a pilot study was conducted to determine the dose of L. monocytogenes required to cause symptomatic listeriosis. In the main trial, mice were divided into 4 groups. Group I was kept as negative control, group II was exposed to L. monocytogenes and maintained as positive control. Group III was fed with L. brevis only, while group IV received L. brevis for 3 days prior to L. monocytogenes infection. A volume of 200 μl of L. monocytogenes ATCC 19115 and L. brevis MF179529 bacterial suspension corresponding to cell density of 10⁹CFU/ml were given to respective groups by intragastric route. Progress of infection was monitored for 7 days including general health scoring, listeria dispersion in organs, bacterial load in intestine and blood biochemistry were recorded on 3rd, 5th and 7th days post infection (dpi).

Results

Clinical listeriosis was induced by 10⁹CFU/ml of L. monocytogenes ATCC 19115 in mice.

Animals of group IV displayed minor signs of infection. L. brevis supplementation resulted in significant reduction in dispersion and propagation of L. monocytogenes in liver, spleen and intestine. L. brevis MF179529 consumption led to a significant elevation of number of lactic acid bacteria and reduction of total plate count, anaerobic count and coliform population in intestine. Moreover, total leukocyte and neutrophil counts of treated animals were similar to the negative control while positive control group displayed higher number. Safety evaluation of L. brevis was performed by monitoring general health, hematological and serological parameters of L. brevis fed and negative control group (group III and I). No significant difference in feed intake, body temperature, body weight and blood picture could be detected in L. brevis supplemented and control groups.

Conclusion

Our results indicate ameliorative role of L. brevis in L. monocytogenes infection and suggest that L. brevis could be used for prophylactic measure.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2444-5) contains supplementary material, which is available to authorized users.

Aloe vera Is Effective and Safe in Short-term Treatment of Irritable Bowel Syndrome: A Systematic Review and Meta-analysis

BACKGROUND/AIMS

To evaluate the efficacy and safety of Aloe vera (AV) in patients with irritable bowel syndrome (IBS).

METHODS

We searched the MEDLINE, EMBASE, and Cochrane databases for studies dated between 1st January 1960 and 30th December 2017. Eligible randomized controlled trials (RCTs) compared AV to placebo in patients with IBS. The primary outcome was standardized mean difference of the change in severity of IBS symptoms as measured by patient-rated scales. Secondary outcomes included response rate of IBS symptoms and adverse events. Heterogeneity among studies was assessed using Cochrane's Q and I2 statistics.

RESULTS

Three RCTs with a total of 151 patients with IBS were included. The meta-analysis showed a significant difference for patients with AV compared to those with placebo regarding improvement in IBS symptom score (standardized mean difference, 0.41; 95% CI, 0.07-0.75; P = 0.020). Using intention-to-treat analysis, the AV patients showed significantly better response rates of IBS symptoms compared to placebo (pooled risk ratio, 1.69; 95% CI, 1.05-2.73; P = 0.030). No adverse events related with AV were found in included studies. There was no significant heterogeneity of effects across studies (P = 0.900; I2 = 0%).

CONCLUSION

AV is effective and safe for the treatment of patients with IBS compared to placebo.

Dysbiosis in Functional Bowel Disorders

Functional bowel disorders (FBD) resemble a group of diseases of the gastrointestinal (GI) tract that are without a clear pathogenesis; the best known is probably the "irritable bowel syndrome" (IBS). Only recently we have been able to explore the role of the gut microbiota in FBD due to progress in microbiological analytic techniques. There are different ways to explore the role of the gut microbiota and its dysbiosis in FBD. Comparison of the microbial composition in a group of patients with FBD, for example, with IBS to a group of healthy volunteers is one way. Studies have shown that the microbiota in FBD is different from that of healthy controls, but the recorded differences are not necessarily specific for FBD, they may also occur in other diseases. Another approach to explore the role of the gut microbiota in FBD is to challenge the existing "flora" with novel bacteria (probiotics) or with nutritional substrates that stimulate bacterial growth (prebiotics). More than 60 such trials including several thousand patients have been performed in IBS. These studies have produced mixed outcome: some probiotics appear to be better than others, and some appear to work only for a part of the IBS symptoms and not for all. An extreme form of this approach is the transfer of an entire microbiota from 1 healthy person to another, called fecal microbiota transplantation. This has rarely been tested in FBD but is not without risk in benign disorders.

The role of the microbiome and the use of probiotics in gastrointestinal disorders in adults in the Asia-Pacific region - background and recommendations of a regional consensus meeting

The Asia-Pacific region is diverse, with regard to ethnicity, culture, and economic development incorporating some of the world's least and most developed nations. Gastrointestinal diseases are common in the Asia-Pacific region, and their prevalence, presentation, and management vary considerably within the region. There is growing evidence for an important role for the human gut microbiota in gastrointestinal health. As a consequence, geographic variations in the composition of the gut microbiota may contribute to variations in both the prevalence and response to therapy of specific diseases. Probiotics have been proposed as a valuable option in the prevention and treatment of a number of gastrointestinal illnesses, but the quality of available evidence to support their efficacy is variable. A meeting of international experts in adult and pediatric gastroenterology was held at the Sorbonne University, Paris, France, on April 11 and 12, 2016, to discuss current evidence supporting the use of probiotics in gastrointestinal disorders in the Asia-Pacific region. This article provides an overview of the discussions held at this meeting and recommends the formation of an Asia-Pacific Consortium on Gut Microbiota similar to those established in Europe and North America.

Effect of combined consumption of Lactobacillus brevis KB290 and β-carotene on minor diarrhoea-predominant irritable bowel syndrome-like symptoms in healthy subjects: a randomised, double-blind, placebo-controlled, parallel-group trial

People with non-pathological diarrhoea-predominant irritable bowel syndrome (IBS-D)-like symptoms are present at a significant level even in healthy populations, but established prophylaxis is lacking. Previously, we have found that co-administration of Lactobacillus brevis KB290 (KB290) and β-carotene (βC) attenuated murine colitis (potential cause of IBS-D-like symptoms) significantly. Here, we investigated the effect of KB290 and βC on minor IBS-D-like symptoms in healthy volunteers. After a 4-week run-in period, subjects received a KB290 + βC or placebo capsule for 12 weeks, followed by a 4-week washout period. The KB290 + βC group showed a significant improvement in intensity of abdominal pain and stool frequency compared with the placebo group. The KB290 + βC group showed a significantly higher serum concentration of anti-inflammatory cytokine, interleukin-10, compared with the placebo group. In conclusion, we demonstrated that consumption of KB290 + βC improves minor IBS-D-like symptoms and inflammatory status in healthy volunteers. (UMIN000018002).

The Genomic Basis of Lactobacilli as Health-Promoting Organisms

Lactobacilli occupy a unique position in human culture and scientific history. Like brewer's and baker's yeast, lactobacilli have been associated with food production and preservation for thousands of years. Lactobacillus species are used in mixed microbial cultures, such as the classical Lactobacillus bulgaricus/Streptococcus thermophilus inoculum for yogurt fermentation, or combinations of diverse lactobacilli/yeasts in kefir grains. The association of lactobacilli consumption with greater longevity and improved health formed the basis for developing lactobacilli as probiotics, whose market has exploded worldwide in the past 10 years. The decade that followed the determination of the first genome sequence of a food-associated species, Lactobacillus plantarum, saw the application to lactobacilli of a full range of functional genomics methods to identify the genes and gene products that govern their distinctive phenotypes and health associations. In this review, we will briefly remind the reader of the range of beneficial effects attributed to lactobacilli, and then explain the phylogenomic basis for the distribution of these traits across the genus. Recognizing the strain specificity of probiotic effects, we review studies of intraspecific genomic variation and their contributions to identifying probiotic traits. Finally we offer a perspective on classification of lactobacilli into new genera in a scheme that will make attributing probiotic properties to clades, taxa, and species more logical and more robust.

Probiotic Therapy of the Irritable Bowel Syndrome: Why Is the Evidence Still Poor and What Can Be Done About It?

BACKGROUND/AIMS

Despite numerous randomized clinical trials and meta-analyses, there is no increased evidence for the efficacy of probiotics in the treatment of irritable bowel syndrome (IBS). We review this evidence, identify and analyse the reasons for this lack of evidence and propose methodological improvements for future studies.

METHODS

Based on a literature search, we identified 56 papers that matched the purpose of our analyses. Twenty-seven studies used multi-species bacterial preparations and 29 used single-strain probiotics. They were analysed regarding patients included, treatment duration, probiotic dosage, and outcome measures.

RESULTS

Trials in both groups suffered from heterogeneity with respect to probiotic concentration, duration of treatment, and other methodological issues (crossover design and underpowered studies). This heterogeneity did not allow the application of a meta-analytic approach and a systematic review was therefore performed instead. Multi-strain preparations combined 2 to 8 different bacterial subspecies, mostly lactobacilli or bifidobacteria, and used variable lengths of treatments. Overall, more than 50% of trials presented negative outcomes. The majority of the single-strain probiotic trials employing lactobacilli or Saccharomyces were negative, whereas trials employing bifidobacteria showed positive results.

CONCLUSIONS

The heterogeneity of the studies of probiotics in IBS questions the value of meta-analyses. The use of different bacterial strains and different mixtures of these strains, as well as different dosages, are the main contributors to this heterogeneity. Current data provides limited evidence for the efficacy of a small number of single-strain probiotics in IBS (mostly bifidobacteria) and sound studies following strict trial guidelines (Food and Drug Administration and European Medicines Agency guidelines for clinical trials) are needed. We summarised and proposed some methodological issues for future studies in the field.

Growth characteristics of Lactobacillus brevis KB290 in the presence of bile

Live Lactobacillus brevis KB290 have several probiotic activities, including immune stimulation and modulation of intestinal microbial balance. We investigated the adaptation of L. brevis KB290 to bile as a mechanism of intestinal survival. Strain KB290 was grown for 5 days at 37 °C in tryptone-yeast extract-glucose (TYG) broth supplemented with 0.5% sodium acetate (TYGA) containing 0.15%, 0.3%, or 0.5% bile. Growth was determined by absorbance at 620 nm or by dry weight. Growth was enhanced as the broth's bile concentration increased. Bile-enhanced growth was not observed in TYG broth or with xylose or fructose as the carbon source, although strain KB290 could assimilate these sugars. Compared with cells grown without bile, cells grown with bile had twice the cell yield (dry weight) and higher hydrophobicity, which may improve epithelial adhesion. Metabolite analysis revealed that bile induced more lactate production by glycolysis, thus enhancing growth efficiency. Scanning electron microscopy revealed that cells cultured without bile for 5 days in TYGA broth had a shortened rod shape and showed lysis and aggregation, unlike cells cultured for 1 day; cells grown with bile for 5 days had an intact rod shape and rarely appeared damaged. Cellular material leakage through autolysis was lower in the presence of bile than in its absence. Thus lysis of strain KB290 cells cultured for extended periods was suppressed in the presence of bile. This study provides new role of bile and sodium acetate for retaining an intact cell shape and enhancing cell yield, which are beneficial for intestinal survival.

Characterisation and preliminary lipid-lowering evaluation of Lactobacillus isolated from a traditional Serbian dairy product

We investigated the potential probiotic properties of indigenous lactic acid bacteria (LAB) isolated from Serbian homemade cheese. Seventeen LAB strains were isolated and characterised using standard protocols. One of the strains showed several probiotic properties: survival at low pH and in bile salts solution, antimicrobial activity, susceptibility to antibiotics and adhesion to hexodecane. DNA analysis identified the isolate as Lactobacillus casei, hereafter named L. casei 5s. The lipid lowering effect of L. casei 5s was evaluated in vivo using a hyperlipidemic rat model. Orally administered L. casei 5s significantly decreased the elevated total serum cholesterol and triglycerides, and attenuated macro vesicular steatosis in the liver. Moreover, L. casei 5s improved the intestinal microbial balance in favour of lactobacilli, while decreasing the number of Escherichia coli cells. The bacteria were re-isolated and identified from the surface of the intestinal mucosa and from the faecal samples of treated animals, indicating adhesiveness and colonisation ability. The results of an acute oral toxicity study in mice and the absence of translocation to other organs demonstrated the safety of the strain. In conclusion, L. casei 5s demonstrated promising probiotic potential and might be a good candidate for more detailed investigations.

Cell-bound exopolysaccharides of Lactobacillus brevis KB290 enhance cytotoxic activity of mouse splenocytes

AIMS

This study aimed to identify the main active component of Lactobacillus brevis KB290 (KB290) that is responsible for enhanced cell-mediated cytotoxic activity of mouse splenocytes Live KB290, a probiotic strain derived from a Japanese traditional pickle, was previously reported to modulate innate immune responses as affecting on cell-mediated cytotoxic activity of mouse splenocytes.

METHODS AND RESULTS

We used live KB290, heat-killed KB290, a derivative strain (Lact. brevis KB392) with different amounts of cell-bound exopolysaccharide (EPS-b), and a crude extract of EPS-b from KB290 cell surface. Female BALB/c mice were fed a diet containing 10(10) CFU live KB290, 10(10) CFU live KB392, 15 mg heat-killed KB290 or 600 μg crude extract of EPS-b for 1 day. Live KB290 (P < 0.01), heat-killed KB290 (P < 0.05) and crude EPS-b at 600 μg (P < 0.05) per mouse significantly enhanced cytotoxic activity; however, live KB392 had no effect.

CONCLUSIONS

Both live and heat-killed KB290 and crude EPS-b significantly enhanced cytotoxic activity of mouse splenocytes.

SIGNIFICANCE AND IMPACT OF THE STUDY

We demonstrated that EPS-b produced by KB290 has a critical role in enhancing cell-mediated cytotoxic activity in mouse spleen.

Effects of probiotic Lactobacillus brevis KB290 on incidence of influenza infection among schoolchildren: an open-label pilot study

We investigated the efficacy of dietary consumption of Lactobacillus brevis KB290 (KB290) against influenza in humans by a preliminary intervention study on elementary schoolchildren, using a commercially available probiotic drink. Subjects were divided into Groups A and B, and an open-label, parallel-group trial was conducted in two 8-week periods at a 1-month interval in winter 2013/2014. Group A was provided with a bottle of the test drink containing KB290 (about 6 billion colony-forming units) every school day in the first period and had no treatment in the second period, and vice versa for Group B. Epidemic influenza was not observed during the first period and only two of 1783 subjects were diagnosed. In the second period, the incidence of influenza in Groups A (no treatment) and B (provided the test drink) was 23·9 and 15·7%, respectively, and the difference was statistically significant (P < 0·001). The reduction in the incidence of influenza by KB290 consumption was especially remarkable in unvaccinated individuals. This is believed to be the first study to show a probiotic food reducing the incidence of influenza in schoolchildren, although further studies are needed to confirm the effectiveness of the probiotic strain KB290.

SIGNIFICANCE AND IMPACT OF THE STUDY

We demonstrated a reduction in the incidence of influenza in 1089 schoolchildren by continual intake of a probiotic drink containing Lactobacillus brevis KB290 (KB290), isolated from a traditional Japanese pickle 'Suguki'. The effect was especially evident in subjects not inoculated with influenza vaccine. This is believed to be the first report to show reduced incidence of influenza in schoolchildren taking a probiotic food. Further studies are needed to confirm the effectiveness of the probiotic strain KB290, which may be useful in the development of potential anti-influenza agents derived from common foods.

Cellular fatty acid composition and exopolysaccharide contribute to bile tolerance in Lactobacillus brevis strains isolated from fermented Japanese pickles

Bile tolerance is a fundamental ability of probiotic bacteria. We examined this property in 56 Lactobacillus brevis strains isolated from Japanese pickles and also evaluated cellular fatty acid composition and cell-bound exopolysaccharide (EPS-b) production. The bile tolerance of these strains was significantly lower in modified de Man – Rogosa – Sharpe (MRS) medium (without Tween 80 or sodium acetate) than in standard MRS medium. Aggregating strains showed significantly higher bile tolerance than nonaggregating strains in MRS medium, but there was no significant difference in the modified MRS media. The relative octadecenoic acid (C18:1) content of the 3 most tolerant aggregating and nonaggregating strains was significantly higher when bile was added to MRS. In MRS without Tween 80, the relative C18:1 content was only marginally affected by addition of bile. In MRS without sodium acetate, only the 3 most tolerant nonaggregating strains increased their relative C18:1 content in the presence of bile. Meanwhile, culture in MRS without sodium acetate reduced EPS-b production in aggregating strains. In conclusion, both EPS-b and cellular fatty acid composition play important roles in bile tolerance of pickle-derived L. brevis.

Growth and bile tolerance of Lactobacillus brevis strains isolated from Japanese pickles in artificial digestive juices and contribution of cell-bound exopolysaccharide to cell aggregation

Cell-bound exopolysaccharide (EPS) of the aggregable strain Lactobacillus brevis KB290 isolated from traditional Japanese pickles has been reported to protect against the effects of bile. However, there are no reports of bile tolerance mechanisms for other L. brevis strains that have aggregability. To elucidate the mechanism of bile tolerance of L. brevis KB290, we found 8 aggregable L. brevis strains out of 121 L. brevis strains isolated from traditional Japanese fermented pickles. We estimated their growth in artificial digestive juice and the amount of cell-bound EPS. We found 3 types of aggregation for these strains: filiform (<1 mm), medium floc (1–5 mm), or large floc (>5 mm). There was no significant difference in growth between nonaggregable and aggregable strains in the artificial digestive juice. The large floc strains selected from the aggregation strains showed significantly higher growth in the artificial digestive juice than nonaggregable strains. In medium and large floc strains, cell-bound EPS, mainly consisting of glucose, N-acetylglucosamine, and N-acetylmannosamine, were observed. The amount of EPS and each strain’s growth index showed a positive correlation. We conclude that aggregable L. brevis strains were also protected by cell-bound EPS.

Sequential gene expression profiling in the mouse spleen during 14 d feeding with Lactobacillus brevis KB290

Some lactic acid bacteria play an important role in the immune system with potential benefits to the host. However, detailed mechanisms of immune modulation exerted by probiotics remain to be clarified. Since immune response changes in a time-related manner in some cases, we monitored changes in mRNA levels in the spleen of mice during 14 d feeding with Lactobacillus brevis KB290 (KB290). Female BALB/c mice, aged 9 weeks, commenced a diet containing KB290 (3 × 109 colony-forming units/g) or starch for a period of 1, 4, 7 or 14 d. Cytotoxic activity of the resulting splenocytes against YAC-1 cells was measured using flow cytometry. The activity was found to be significantly higher in the treated group on days 1 and 7. The highest activity appeared on day 4, but was not statistically significantly different. Gene expression profiles were analysed using DNA microarray. Gene Ontology (GO) terms related to the immune process were significantly enriched in the up-regulated gene set on days 1, 4 and 7, and GO terms related to the cellular process were enriched in the down-regulated gene set on days 4 and 7. Although the up-regulated genes involved in antigen processing and presentation for stimulation of CD8+ cytotoxic T cells were not observed on day 14, some genes involved in T-cell and natural killer cell activation remained up-regulated until day 14. For the majority of the genes tested, RT-PCR analysis was used to verify the results obtained from the DNA microarray analysis. The sequential gene expression profiling reflected changes in cytotoxic activity during KB290 feeding.

Oral administration of Lactobacillus brevis KB290 to mice alleviates clinical symptoms following influenza virus infection

Lactobacillus brevis KB290 (KB290), isolated from a traditional Japanese pickle 'Suguki', has been reported to have immunomodulatory effects. We investigated whether oral administration of KB290 has protective effects against influenza virus (IFV) infection in mice. After 14 days of administration of lyophilized KB290 suspended in phosphate-buffered saline by oral gavage, BALB/c mice were intranasally infected with 2 × MLD50 (50% mouse lethal dose) of IFV A/PR/8/34 (H1N1). Prophylactically administered KB290 significantly alleviated the loss of body weight and the deterioration in observational physical conditions induced by the infection. In addition, 7 days after infection, the levels of IFV-specific immunoglobulin (Ig)A in bronchoalveolar lavage fluid were significantly increased in mice fed KB290 compared with controls. Moreover, there was a significant elevation of serum interferon (IFN)-α in KB290 group mice, even at three and 7 days after infection, despite the administration of KB290 being stopped before IFV infection. Our results demonstrated that oral administration of KB290 before infection could alleviate IFV-induced clinical symptoms. Alleviation of clinical symptoms by KB290 consumption may have been induced by long-lasting enhancement of IFN-α production and the augmentation of IFV-specific IgA production.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrated that oral administration of Lactobacillus brevis KB290 (KB290), a probiotic strain derived from a Japanese traditional pickle, could protect against influenza virus (IFV) infection in mice. Our results demonstrated that continual intake of KB290 for 14 days prior to IFV infection alleviated clinical symptoms such as loss of body weight and deterioration in observational physical conditions induced by the infection. The beneficial effects of KB290 consumption may have been elicited by the long-lasting enhancement of interferon-α production and the augmentation of IFV-specific immunoglobulin A production.

Cell-bound exopolysaccharides of Lactobacillus brevis KB290: protective role and monosaccharide composition

We examined the survivability of Lactobacillus brevis KB290 and derivative strain KB392 in artificial digestive juices and bile salts. The strains have similar membrane fatty acids but different amounts of cell-bound exopolysaccharides (EPS). In artificial digestive juices, KB290 showed significantly higher survivability than KB392, and homogenization, which reduced the amount of EPS in KB290 but not in KB392, reduced the survivability only of KB290. In bile salts, KB290 showed significantly higher survivability than KB392, and cell-bound EPS extraction with EDTA reduced the survivability of only KB290. Transmission electron microscopy showed there to be a greater concentration of cell-bound EPS in KB290 than in either KB392 or EDTA-treated or homogenized KB290. We conclude that KB290's cell-bound EPS (which high performance liquid chromatography showed to be made up of glucose and N-acetylglucosamine) played an important role in bile salt tolerance.

Effect of Lactobacillus brevis KB290 on the cell-mediated cytotoxic activity of mouse splenocytes: a DNA microarray analysis

Lactic acid bacteria confer a variety of health benefits. Here, we investigate the mechanisms by which Lactobacillus brevis KB290 (KB290) enhances cell-mediated cytotoxic activity. Female BALB/c mice aged 9 weeks were fed a diet containing KB290 (3 × 10(9) colony-forming units/g) or starch for 1 d. The resulting cytotoxic activity of splenocytes against YAC-1 cells was measured using flow cytometry and analysed for gene expression using DNA microarray technology. KB290 enhanced the cell-mediated cytotoxic activity of splenocytes. DNA microarray analysis identified 327 up-regulated and 347 down-regulated genes that characterised the KB290 diet group. The up-regulated genes were significantly enriched in Gene Ontology terms related to immunity, and, especially, a positive regulation of T-cell-mediated cytotoxicity existed among these terms. Almost all the genes included in the term encoded major histocompatibility complex (MHC) class I molecules involved in the presentation of antigen to CD8(+) cytotoxic T cells. Marco and Signr1 specific to marginal zone macrophages (MZM), antigen-presenting cells, were also up-regulated. Flow cytometric analysis confirmed that the proportion of MZM was significantly increased by KB290 ingestion. Additionally, the over-represented Kyoto Encyclopedia of Genes and Genomes pathways among the up-regulated genes were those for natural killer (NK) cell-mediated cytotoxicity and antigen processing and presentation. The results for the selected genes associated with NK cells and CD8(+) cytotoxic T cells were confirmed by quantitative RT-PCR. These results suggest that enhanced cytotoxic activity could be caused by the activation of NK cells and/or of CD8(+) cytotoxic T cells stimulated via MHC class I presentation.

Genomic analysis by deep sequencing of the probiotic Lactobacillus brevis KB290 harboring nine plasmids reveals genomic stability

We determined the complete genome sequence of Lactobacillus brevis KB290, a probiotic lactic acid bacterium isolated from a traditional Japanese fermented vegetable. The genome contained a 2,395,134-bp chromosome that housed 2,391 protein-coding genes and nine plasmids that together accounted for 191 protein-coding genes. KB290 contained no virulence factor genes, and several genes related to presumptive cell wall-associated polysaccharide biosynthesis and the stress response were present in L. brevis KB290 but not in the closely related L. brevis ATCC 367. Plasmid-curing experiments revealed that the presence of plasmid pKB290-1 was essential for the strain's gastrointestinal tract tolerance and tendency to aggregate. Using next-generation deep sequencing of current and 18-year-old stock strains to detect low frequency variants, we evaluated genome stability. Deep sequencing of four periodic KB290 culture stocks with more than 1,000-fold coverage revealed 3 mutation sites and 37 minority variation sites, indicating long-term stability and providing a useful method for assessing the stability of industrial bacteria at the nucleotide level.