Lactobacillus plantarum 299v enhances the concentrations of fecal short-chain fatty acids in patients with recurrent clostridium difficile-associated diarrhea

Lactiplantibacillus plantarum P9 for chronic diarrhea in young adults: a large double-blind, randomized, placebo-controlled trial

Current treatments for chronic diarrhea have limited efficacy and several side effects. Probiotics have the potential to alleviate symptoms of diarrhea. This randomized, double-blind, placebo-controlled trial evaluates the effects of administering the probiotic Lactiplantibacillus plantarum P9 (P9) strain in young adults with chronic diarrhea (Clinical Trial Registration Number: ChiCTR2000038410). The intervention period lasts for 28 days, followed by a 14-day post-intervention period. Participants are randomized into the P9 (n = 93) and placebo (n = 96) groups, with 170 individuals completing the double-blind intervention phase (n = 85 per group). The primary endpoint is the diarrhea symptom severity score. Both intention-to-treat (n = 189) and per-protocol (n = 170) analyses reveal a modest yet statistically significant reduction in diarrhea severity compared to the placebo group (20.0%, P = 0.050; 21.4%, P = 0.048, respectively). In conclusion, the results of this study support the use of probiotics in managing chronic diarrhea in young adults. However, the lack of blood parameter assessment and the short intervention period represent limitations of this study.

The Immunomodulatory Effects and Applications of Probiotic Lactiplantibacillus plantarum in Vaccine Development

Lactiplantibacillus plantarum (previously known as Lactobacillus plantarum) is a lactic acid bacterium that exists in various niches. L. plantarum is a food-grade microorganism that is commonly considered a safe and beneficial microorganism. It is widely used in food fermentation, agricultural enhancement, and environmental protection. L. plantarum is also part of the normal flora that can regulate the intestinal microflora and promote intestinal health. Some strains of L. plantarum are powerful probiotics that induce and modulate the innate and adaptive immune responses. Due to its outstanding immunoregulatory capacities, an increasing number of studies have examined the use of probiotic L. plantarum strains as natural immune adjuvants or alternative live vaccine carriers. The present review summarizes the main immunomodulatory characteristics of L. plantarum and discusses the preliminary immunological effects of L. plantarum as a vaccine adjuvant and delivery carrier. Different methods for improving the immune capacities of recombinant vector vaccines are also discussed.

The predicted mechanisms and evidence of probiotics on type 2 diabetes mellitus (T2DM)

Type 2 diabetes mellitus (T2DM) is a serious endocrine and metabolic disease that is highly prevalent and causes high mortality and morbidity rates worldwide. This review aims to focus on the potential of probiotics in the management of T2DM and its complications and to summarise the various mechanisms of action of probiotics with respect to T2DM. In this review, experimental studies conducted between 2016 and 2022 were explored. The possible mechanisms of action are based on their ability to modulate the gut microbiota, boost the production of short-chain fatty acids (SCFAs) and glucagon-like peptides, inhibit α-glucosidase, elevate sirtuin 1 (SIRT1) levels while reducing fetuin-A levels, and regulate the level of inflammatory cytokines. This review recommends carrying out further studies, especially human trials, to provide robust evidence-based knowledge on the use of probiotics for the treatment of T2DM.IMPACT STATEMENTT2DM is prevalent worldwide causing high rates of morbidity and mortality.Gut microbiota play a significant role in the pathogenesis of T2DM.Probiotics can be used as possible therapeutic tools for the management of T2DM.The possible mechanisms of action of probiotics include modulation of the gut microbiota, production of SCFAs and glucagon-like peptides, inhibition of α-glucosidase, raising SIRT1, reducing fetuin-A levels, and regulating the level of inflammatory cytokines.

Gut microbe-derived metabolites and the risk of cardiovascular disease in the METSIM cohort

Background

An association between gut microbes and cardiovascular disease (CVD) has been established, but the underlying mechanisms remain largely unknown.

Methods

We conducted a secondary analysis of the cross-sectional data obtained from the Metabolic Syndrome in Men (METSIM) population-based cohort of 10,194 Finnish men (age = 57.65 ± 7.12 years). We tested the levels of circulating gut microbe-derived metabolites as predictors of CVD, ischemic cerebrovascular accident (CVA), and myocardial infarction (MI). The Kaplan-Meier method was used to estimate the time from the participants' first outpatient clinic visit to the occurrence of adverse outcomes. The associations between metabolite levels and the outcomes were assessed using Cox proportional hazard models.

Results

During a median follow-up period of 200 months, 979 participants experienced CVD, 397 experienced CVA, and 548 experienced MI. After adjusting for traditional risk factors and correcting for multiple comparisons, higher plasma levels of succinate [quartile 4 vs. quartile 1; adjusted hazard ratio, aHR = 1.30, (confidence interval (CI), 1.10-1.53) p = 0.0003, adjusted p = 0.01] were significantly associated with the risk of CVD. High plasma levels of ursodeoxycholic acid (UDCA) (quartile 3 vs. quartile 1); [aHR = 1.68, (CI, 1.26-2.2); p = 0.0003, adj. p = 0.01] were associated with a higher risk of CVA. Furthermore, as a continuous variable, succinate was associated with a 10% decrease in the risk of CVD [aHR = 0.9; (CI, 0.84-0.97); p = 0.008] and a 15% decrease in the risk of MI [aHR = 0.85, (CI, 0.77-0.93); p = 0.0007].

Conclusion

Gut microbe-derived metabolites, succinate, and ursodeoxycholic acid were associated with CVD, MI, and CVA, respectively. Regulating the gut microbes may represent a potential therapeutic target for modulating CVD and CVA.

Strategies for applying probiotics in the antibiotic management of Clostridioides difficile infection

The vital role of probiotics in the food field has been widely recognized, and at the same time, probiotics are gradually exhibiting surprising effects in the field of nutraceuticals, especially in regulating gut inflammation and the nutritional environment. As a dietary supplement in clinical nutrition, the coadministration of probiotics with antibiotics model has been applied to prevent intestinal infections caused by Clostridioides difficile. However, the mechanism behind this "bacteria-drug combination" model remains unclear. In particular, the selection of specific probiotic strains, the order of probiotics or antibiotics, and the time interval of coadministration are key issues that need to be further explored and clarified. Here, we focus on the issues mentioned above and give reasonable opinions, mainly including: (1) probiotics are safer and more effective when they intervene after antibiotics have been used; (2) the choice of the time interval between coadministration should be based on the metabolism of antibiotics in the host, differences in probiotic strains, the baseline ecological environment of the host's intestine, and the host immune level; in addition, the selection of the coadministration regime should also take into account factors such as the antibiotic sensitivity of probiotics and dosage of probiotics; and (3) by encapsulating probiotics, combining probiotics with prebiotics, and developing next-generation probiotics (NGPs) and postbiotic formulations, we can provide a more reasonable reference for this type of "bacteria-drug combination" model, and also provide targeted guidance for the application of probiotic dietary supplements in the antibiotic management of C. difficile infection.

Short chain fatty acids: the messengers from down below

Short-chain fatty acids (SCFAs), produced by the metabolism of dietary fibers in the gut, have wide-ranging effects locally and throughout the body. They modulate the enteric and central nervous systems, benefit anti-inflammatory pathways, and serve as energy sources. Recent research reveals SCFAs as crucial communicators between the gut and brain, forming the gut-brain axis. This perspective highlights key findings and discusses signaling mechanisms connecting SCFAs to the brain. By shedding light on this link, the perspective aims to inspire innovative research in this rapidly developing field.

Clinical trial of a probiotic and herbal supplement for lung health

Introduction

Dysbiosis of the gut microbiome may augment lung disease via the gut-lung axis. Proteobacteria may contribute to tissue proteolysis followed by neutrophil recruitment, lung tissue injury, and perpetuation of chronic inflammation. To study the effects of probiotics across the gut-lung axis, we sought to determine if a Lactobacillus probiotic and herbal blend was safe and well-tolerated in healthy volunteers and asthmatic patients.

Methods

We conducted a 1-month randomized, open-label clinical trial in Cork, Ireland with healthy and asthmatic patients who took the blend twice a day. The primary endpoint was safety with exploratory endpoints including quality of life, lung function, gut microbiome ecology, and inflammatory biomarkers.

Results

All subjects tolerated the blend without adverse events. Asthmatic subjects who took the blend showed significant improvements in lung function as measured by forced expiratory volume and serum short chain fatty acid levels from baseline to Week 4. The gut microbiome of asthmatic subjects differed significantly from controls, with the most prominent difference in the relative abundance of the proteobacteria Escherichia coli. Administration of the probiotic maintained overall microbial community architecture with the only significant difference being an increase in absolute abundance of the probiotic strains measured by strain-specific PCR.

Conclusion

This study supports the safety and efficacy potential of a Lactobacillus probiotic plus herbal blend to act on the gut-lung axis. However, due to the lack of a control group, a longer blinded, placebo-controlled study will be warranted to confirm the efficacy improvements observed in this trial.

Clinical trial registration

https://clinicaltrials.gov/, identifier NCT05173168.

Antibacterial Activity and Toxicity of Zinc Oxide Nanoparticles Combined with Supernatants of Lactobacillus spp. Against ESKAPE Bacteria: A Novel Mixture

Background

The emergence of multidrug resistance among nosocomial pathogens has prompted researchers to look for new antibacterial sources. Metal nanoparticles and probiotic products have attracted the attention of researchers. However, combination therapy is an attractive alternative in this field.

Objectives

This study evaluated the antibacterial activity and toxicity of Zinc Oxide nanoparticles (ZnO-NPs) combined with cell-free supernatant (CFS) of Lactobacillus plantarum and Lactobacillus acidophilus alone and in a novel mixture.

Methods

Antibacterial effects and cytotoxic properties of ZnO-NPs, CFS of L. plantarum (SLP), and CFS of L. acidophilus (SLA) were determined alone and in a mixture against ESKAPE strains. In addition, the viability percentage of the cells was evaluated after exposure to these agents.

Results

Antibacterial mixtures (ZnO-NPs with SLP or ZnO-NPs with SLA) demonstrated synergistic and additive effects against Pseudomonas aeruginosa (FIC≤0.75), Acinetobacter baumannii (FIC = 1), and Escherichia coli (FIC≤0.75). The viability percentage of the cells after 24 h of exposure to a mixture of ZnO-NPs and SLA (about 50%) was more than when the cells were exposed to ZnO-NPs alone (about 30%) at the same concentration.

Conclusions

A mixture of ZnO-NPs and CFS of probiotics can be an alternative to antibiotics, with more effectiveness and fewer side effects.

Efficacy of a Probiotic and Herbal Supplement in Models of Lung Inflammation

Background: Gut microbiome dysbiosis is associated with lung disease through the gut-lung axis. Abundant proteobacteria increase MMP-9 and contribute to tissue proteolysis followed by neutrophil recruitment, lung tissue injury, and perpetuation of chronic lung disease. We sought to determine if a scientifically formulated probiotic and herbal supplement could attenuate neutrophilic inflammation and improve lung structure and function in models of lung inflammation. Methods: For in vitro experiments, epithelial cells exposed to proteobacteria were treated with resB—a blend of three probiotic Lactobacillus strains and turmeric, holy basil, and vasaka herbal extracts. For in vivo experimentation, mice exposed to pulmonary proteobacteria-derived lipopolysaccharide were treated by gavage with resB. Results: In vitro, the bacterial and herbal components of resB decreased activity of the MMP-9 pathway. Mice exposed to LPS and pre- and post-treated with resB had decreased neutrophil recruitment and inflammatory biomarkers in bronchoalveolar lavage fluid, serum, and lung tissue compared to untreated mice. Conclusions: This study describes the mechanisms and efficacy of probiotic and herbal blend in pre-clinical models of lung injury and inflammation.

Bifidobacterium animalis subsp. lactis XLTG11 improves antibiotic-related diarrhea by alleviating inflammation, enhancing intestinal barrier function and regulating intestinal flora

Antibiotic-associated diarrhea (AAD) is a common side effect during antibiotic treatment. In this study, we evaluated the regulatory effect of Bifidobacterium animalis subsp. lactis XLTG11 on mouse diarrhea caused by antibiotic-induced intestinal flora disturbance. Then, two strains of Bifidobacterium animalis subsp. lactis XLTG11 and Bifidobacterium animalis subsp. lactis BB-12 were administered to AAD mice. We found that the recovery effect of using B. lactis XLTG11 was better than that of B. lactis BB-12. B. lactis XLTG11 reduced the pathological characteristics of the intestinal tract, and significantly reduced the levels of lipopolysaccharide (LPS), D-lactic acid (D-LA) and diamine oxidase (DAO) to decrease intestinal permeability. In addition, these two strains significantly increased the expression of aquaporin and tight junction proteins, and inhibited toll-like receptor 4 (TLR4)/activation of the nuclear factor-κB (NF-κB) signaling pathway, significantly increased the levels of anti-inflammatory cytokines and decreased levels of pro-inflammatory cytokines. Moreover, after treatment with B. lactis XLTG11, the contents of acetic acid, propionic acid, butyric acid and total short-chain fatty acids were significantly increased. Compared with the MC group, B. lactis XLTG11 increased the abundance and diversity of the intestinal flora and changed the composition of the intestinal flora. We found that B. lactis XLTG11 can promote the recovery of intestinal flora and mucosal barrier function, thereby effectively improving AAD-related symptoms, providing a scientific basis for future clinical applications.

Effect of Oral Intake of Lactiplantibacillus plantarum APsulloc 331261 (GTB1TM) on Diarrhea-Predominant Irritable Bowel Syndrome: A Randomized, Double-Blind, Placebo-Controlled Study

Irritable bowel syndrome (IBS) causes intestinal discomfort, gut dysfunction, and poor quality of life. This randomized, double-blind placebo-controlled trial evaluated the efficacy of Lactiplantibacillus (Lp., formerly Lactobacillus) plantarum APsulloc 331261 (GTB1^TM) from green tea leaves in participants with diarrhea-predominant irritable bowel syndrome (IBS-D). Twenty-seven participants meeting the Rome IV diagnostic criteria were randomized for GTB1 or placebo ingestion for four weeks and follow-up for two weeks. The efficacy endpoints included adequate global relief of symptoms, assessment of intestinal discomfort symptom severity and frequency, stool frequency, satisfaction, and fecal microbiome abundance. Of all participants, 94.4% and 62.5% reported global relief of symptoms in the GTB1 and placebo groups, respectively, with significant differences (p = 0.037). GTB1 significantly reduced the severity and frequency of abdominal pain, bloating, and feeling of incomplete evacuation. The frequencies of diarrhea were decreased −45.89% and −26.76% in the GTB1 and placebo groups, respectively (p = 0.045). Hence, GTB1 ingestion improved IBS-D patient quality of life. After four weeks treatment, the relative abundance of Lactobacillus was higher in the GTB1 than in the placebo group (p = 0.010). Our results showed that GTB1 enhanced intestinal discomfort symptoms, defecation consistency, quality of life, beneficial microbiota, and overall intestinal health.

The development of live biotherapeutics against Clostridioides difficile infection towards reconstituting gut microbiota

Clostridioides difficile is the most prevalent pathogen of nosocomial diarrhea. In the United States, over 450,000 cases of C. difficile infection (CDI), responsible for more than 29,000 deaths, are reported annually in recent years. Because of the emergence of hypervirulent strains and strains less susceptible to vancomycin and fidaxomicin, new therapeutics other than antibiotics are urgently needed. The gut microbiome serves as one of the first-line defenses against C. difficile colonization. The use of antibiotics causes gut microbiota dysbiosis and shifts the status from colonization resistance to infection. Hence, novel CDI biotherapeutics capable of reconstituting normal gut microbiota have become a focus of drug development in this field.

Psychobiotics improve propionic acid-induced neuroinflammation in juvenile rats, rodent model of autism

This study aimed to evaluate the protective and therapeutic potency of bee pollen and probiotic mixture on brain intoxication caused by propionic acid (PPA) in juvenile rats. Five groups of six animals each, were used: the control group only receiving phosphate-buffered saline; the bee pollen and probiotic-treated group receiving a combination of an equal quantity of bee pollen and probiotic (0.2 kg/kg body weight); the PPA group being treated for 3 days with an oral neurotoxic dose of PPA (0.25 kg/kg body weight); the protective and therapeutic groups receiving bee pollen and probiotic mixture treatment right before and after the neurotoxic dose of PPA, respectively. The levels of interleukin (IL)-1ß, IL-6, IL-8, IL-10, IL-12, tumor necrosis factor α, and interferon γ (IFN-γ) were investigated to evaluate the neuroinflammatory responses in brain tissues from different animal groups. The much higher IL-1β, IL-8, and IFN-γ, as pro-inflammatory cytokines (P < 0.001), together with much lower IL-10, as anti-inflammatory cytokine (P < 0.001) compared to controls clearly demonstrated the neurotoxic effects of PPA. Interestingly, the mixture of bee pollen and probiotics was effective in alleviating PPA neurotoxic effects in both therapeutic and protective groups demonstrating highly significant changes in IL-1β, IL-8, IL-10, and IFN-γ levels together with non-significant reduction in IL-6 levels compared to PPA-treated rats. Overall, our findings demonstrated a new approach to the beneficial use of psychobiotics presenting as bee pollen and probiotic combination in neuroinflammation through cytokine changes as a possible role of glial cells in gut–brain axis.

A Randomised, Controlled Trial: Effect of a Multi-Strain Fermented Milk on the Gut Microbiota Recovery after Helicobacter pylori Therapy

Helicobacter pylori (Hp) eradication therapy alters gut microbiota, provoking gastrointestinal (GI) symptoms that could be improved by probiotics. The study aim was to assess the effect in Hp patients of a Test fermented milk containing yogurt and Lacticaseibacillus (L. paracasei CNCM I-1518 and I-3689, L. rhamnosus CNCM I-3690) strains on antibiotic associated diarrhea (AAD) (primary aim), GI-symptoms, gut microbiota, and metabolites. A randomised, double-blind, controlled trial was performed on 136 adults under 14-day Hp treatment, receiving the Test or Control product for 28 days. AAD and GI-symptoms were reported and feces analysed for relative and quantitative gut microbiome composition, short chain fatty acids (SCFA), and calprotectin concentrations, and viability of ingested strains. No effect of Test product was observed on AAD or GI-symptoms. Hp treatment induced a significant alteration in bacterial and fungal composition, a decrease of bacterial count and alpha-diversity, an increase of Candida and calprotectin, and a decrease of SCFA concentrations. Following Hp treatment, in the Test as compared to Control group, intra-subject beta-diversity distance from baseline was lower (p_adj = 0.02), some Enterobacteriaceae, including Escherichia-Shigella (p_adj = 0.0082) and Klebsiella (p_adj = 0.013), were less abundant, and concentrations of major SCFA (p = 0.035) and valerate (p = 0.045) were higher. Viable Lacticaseibacillus strains were detected during product consumption in feces. Results suggest that, in patients under Hp treatment, the consumption of a multi-strain fermented milk can induce a modest but significant faster recovery of the microbiota composition (beta-diversity) and of SCFA production and limit the increase of potentially pathogenic bacteria.

Lactiplantibacillus plantarum 299v (LP299V®): three decades of research

This review aims to provide a comprehensive overview of the in vitro, animal, and clinical studies with the bacterial strain Lactiplantibacillus plantarum 299v (L. plantarum 299v; formerly named Lactobacillus plantarum 299v) published up until June 30, 2020. L. plantarum 299v is the most documented L. plantarum strain in the world, described in over 170 scientific publications out of which more than 60 are human clinical studies. The genome sequence of L. plantarum 299v has been determined and is available in the public domain (GenBank Accession number: NZ_LEAV01000004). The probiotic strain L. plantarum 299v was isolated from healthy human intestinal mucosa three decades ago by scientists at Lund University, Sweden. Thirty years later, a wealth of data coming from in vitro, animal, and clinical studies exist, showing benefits primarily for gastrointestinal health, such as reduced flatulence and abdominal pain in patients with irritable bowel syndrome (IBS). Moreover, several clinical studies have shown positive effects of L. plantarum 299v on iron absorption and more recently also on iron status. L. plantarum 299v is safe for human consumption and does not confer antibiotic resistance. It survives the harsh conditions of the human gastrointestinal tract, adheres to mannose residues on the intestinal epithelial cells and has in some cases been re-isolated more than ten days after administration ceased. Besides studying health benefits, research groups around the globe have investigated L. plantarum 299v in a range of applications and processes. L. plantarum 299v is used in many different food applications as well as in various dietary supplements. In a freeze-dried format, L. plantarum 299v is robust and stable at room temperature, enabling long shelf-lives of consumer healthcare products such as capsules, tablets, or powder sachets. The strain is patent protected for a wide range of indications and applications worldwide as well as trademarked as LP299V^®.

The role of Lactobacillus plantarum 299v in supporting treatment of selected diseases

Alterations in composition of human gut microbiome can lead to its dysbiosis. It is associated with gastrointestinal side effects during anti-cancer treatment, antibiotics administration, or infectious agents. There are studies confirming positive effect of consuming Lactobacillus plantarum 299v on intestinal microflora. This review summarizes the current knowledge about the role of L. plantarum 299v in supporting treatment of selected diseases, such as cancer, irritable bowel syndrome (IBS), and Clostridium difficile infection. The immunomodulating properties of L. plantarum 299v include an increase in the level of anti-inflammatory cytokines, which reduce the risk of cancer and improve the efficacy of regimens. The intake of L. plantarum 299v provides benefits for IBS patients, mainly due to normalization of stool and relief of abdominal pain, which significantly improves the quality of life of IBS patients. In addition, the intake of L. plantarum 299v prevents C. difficile-associated diarrhea among patients receiving antibiotic treatment. Due to the limited possibilities of treating these diseases and numerous complications of cancer treatment, there is a need for new therapeutic strategies. The administration of L. plantarum 299v seems to be useful in these cases.

Comparison of the effects of Lactobacillus plantarum versus imipenem on infected burn wound healing

Background: Infection of burn wounds is one of the most important problems in the world. Lactobacillus plantarum is known for burn wound healing because of the immunomodulatory and anti-microbial roles. This study was performed to compare the effects of L. plantarum and imipenem - alone and in combination - on infected burn wound healing. Methods: Burn wounds were experimentally induced on 50 rats in three test groups (germ and supernatant of L. plantarum ) and two control groups (n=10 each) and were inoculated with Pseudomonas aeruginosa. During a 14-day period, wounds in all groups were daily treated topically. The data were analyzed using one-way analysis of variance followed by Tukey-Kramer and LSD. A p-value of < 0.05 was considered as statistically significant. Results: The mean size of the wound on day 14 after the treatment in the probiotic group was significantly lower than the control and the supernatant treated groups (p<0.05). The percentage of wound healing was significantly higher in the probiotic pellet treated group compared to the imipenem and the supernatant groups (by Anova test: 69.58%, p=0.022). The mean leukocyte count in the probiotic pellet group (12110) and supernatant group (13650) was significantly higher than the imipenem group (7670) (p=0.002 and 0.001, respectively). Wound cultures revealed that the percentage of cases where the pathogens had no growth was significantly different among the comparison groups. In all three test groups, P. aeruginosa was completely eliminated in comparison to the positive control group (p<0.05). Conclusion: The results of our study showed that L. plantarum and its by-products promote wound healing and can be used as an alternative to antibiotics to treat ulcer infections caused by resistant bacteria.

Molecular mechanisms of probiotic prevention of antibiotic-associated diarrhea

Antibiotic-associated diarrhea (AAD) is a common and unintended adverse effect of antibiotic treatment. It is characterized by the disruption of the gut microbiota, decreased intestinal short chain fatty acid (SCFA) concentrations, accumulation of luminal carbohydrates and colonic bile acids, altered water absorption, and ultimately diarrhea. Probiotics were shown to prevent AAD in numerous clinical trials. This review examines what is currently known about how probiotics reduce the risk for AAD via modulating the gut microbiota, altering nutrient and bile acid metabolism, inducing epithelial solute transporter activity, supporting intestinal barrier function, and influencing the immune system. Although probiotics are frequently prescribed with antibiotic use, mechanistic evidence verifying how they confer protection against AAD is extremely limited. This information is urgently needed for improving recommendations for sustaining probiotic development and for implementing probiotics in clinical settings.

Development and validation of a GC-FID method for the analysis of short chain fatty acids in rat and human faeces and in fermentation fluids

Short-chain fatty acids (SCFAs) are gut microbiota metabolites recognized for their beneficial effects on the host organism. In this study, a simple and rapid sample preparation method combined to SCFAs analysis by direct injection and gas chromatography coupled with flame ionization detection (GC-FID), for the determination and quantification of eight SCFAs (acetic, propionic, i-butyric, butyric, i-valeric, valeric, i-caproic and caproic acids) in rat, mice and human faeces and in fermentation fluids samples, has been developed and validated. The method consists of extraction of the SCFAs by ethyl ether after acidification of the samples. The effect of the number of extractions has been assessed in order to optimize the procedure and to obtain a satisfactory yield for all the analyzed SCFAs. The increase of the extracted analytes quantity was significant passing from 1 to 2 and from 2 to 3 extractions (P < 0.05), while no significant differences were found performing 3, 4 or 5 extractions (P > 0.05). The SCFAs extracted are directly analyzed by GC-FID without derivatization and separated on a polyethylene glycol nitroterephthalic acid modified coated capillary column, with a chromatographic run time of 13 min. The proposed method showed good sensitivity, with limits of quantifications in the range 0.14-0.48 µM for SCFAs from propionic to caproic acids and 2.12 µM for acetic acid; recovery was between 80.8 and 108.8% and intraday and interday repeatability in the range 0.6-5.0% of precision (RSD, %) The optimized method is suitable for the quantitative analysis of SCFAs in real samples of rat, mouse and human faeces and in fermentation fluids, and it can be applied also to very small amount of faecal sample (20 mg).

Probiotic Supplementation in a Clostridium difficile-Infected Gastrointestinal Model Is Associated with Restoring Metabolic Function of Microbiota

Clostridium (C.) difficile-infection (CDI), a nosocomial gastrointestinal disorder, is of growing concern due to its rapid rise in recent years. Antibiotic therapy of CDI is associated with disrupted metabolic function and altered gut microbiota. The use of probiotics as an adjunct is being studied extensively due to their potential to modulate metabolic functions and the gut microbiota. In the present study, we assessed the ability of several single strain probiotics and a probiotic mixture to change the metabolic functions of normal and C. difficile-infected fecal samples. The production of short-chain fatty acids (SCFAs), hydrogen sulfide (H₂S), and ammonia was measured, and changes in microbial composition were assessed by 16S rRNA gene amplicon sequencing. The C. difficile-infection in fecal samples resulted in a significant decrease (p < 0.05) in SCFA and H₂S production, with a lower microbial alpha diversity. All probiotic treatments were associated with significantly increased (p < 0.05) levels of SCFAs and restored H₂S levels. Probiotics showed no effect on microbial composition of either normal or C. difficile-infected fecal samples. These findings indicate that probiotics may be useful to improve the metabolic dysregulation associated with C. difficile infection.

Immunomodulatory and anti-inflammatory effects of probiotics in multiple sclerosis: a systematic review

Multiple sclerosis (MS) is an inflammatory and autoimmune neurological disorder which leads to demyelination. Although the etiology of MS is yet to be known, it appears that regulating the immune system and suppressing inflammatory pathways may possibly have a favorable effect on the healing of this disease. Evidence suggests that probiotics consumption via gut microbiome alteration devises beneficial effects in improving immune and inflammatory responses in MS. All articles were systematically searched (in the main databases) for this paper. Two investigators independently scrutinized full texts of the potentially eligible articles. The quality of the study was evaluated using standardized tools. The methodological quality of seven studies included in this review ranged from fair to good. The findings illustrated that there were statistically significant improvements in the static and dynamic balance in patients and animals with MS. In the paper in hand, the effects of probiotics administration on immune and inflammatory markers in MS disease are evaluated. In addition, the limitations and knowledge gaps were reported while proposing a possible mechanism of probiotics therapy in modulating immune and inflammatory responses. This systematic review indicated that the probiotics could improve immune and inflammatory parameters, the cytokines and cells in MS disease. Probiotics may have efficient effects in management and treatment of MS. More studies are required to clarify the effect of supplementation with probiotics and their mechanisms in MS disease.

Effects of Lactobacillus plantarum on the intestinal morphology, intestinal barrier function and microbiota composition of suckling piglets

This study investigated the effect of Lactobacillus plantarum strain 299v on gut health in suckling piglets. Sixty newborn piglets were assigned to control and probiotic treatments, with three litters per treatment (ten piglets/litter). From days 1 to 20 of life, piglets were orally administered a placebo of 0.1% peptone or 1.0 ×  10¹⁰  CFU L. plantarum 299v daily. Six piglets per treatment were sacrificed on day 20, and intestinal tissues (including duodenum, jejunum, ileum and colon) and the intestinal contents from colon segments were collected. The results demonstrated that piglets treated with L. plantarum 299v had a lower diarrhoea incidence than the controls. L. plantarum 299v administration significantly increased the ratio of the villus height to the crypt depth in the jejunum and ileum, as well as the mRNA expression of jejunal occludin and ileal zonula occludens 1 (ZO-1). The L. plantarum treatment also increased the mRNA abundance of porcine β-defensin 2 (pBD2) and pBD3 in the jejunum and ileum and of toll-like receptors (TLRs), such as TLR2, TLR4, TLR6 and TLR9 in the ileum, and significantly upregulated the mRNA abundances of ileal pBD1 and colonic TLR4. Additionally, the L. plantarum 299v treatment significantly changed the structure of the colonic microbiota, as evidenced by the obvious increases in the relative abundances of the phyla Firmicutes and Actinobacteria and of the genus Lactobacillus. Our findings indicate that L. plantarum 299v facilitates the gut health of suckling piglets, probably by improving the intestinal morphology and intestinal barrier function and by modifying the structure of the gut microbiota.

Role of the Microbiota in the Modulation of Vaccine Immune Responses

The human immune system and the microbiota co-evolve, and their balanced relationship is based on crosstalk between the two systems through the course of life. This tight association and the overall composition and richness of the microbiota play an important role in the modulation of host immunity and may impact the immune response to vaccination. The availability of innovative technologies, such as next-generation sequencing (NGS) and correlated bioinformatics tools, allows a deeper investigation of the crosstalk between the microbiota and human immune responses. This review discusses the current knowledge on the influence of the microbiota on the immune response to vaccination and novel tools to deeply analyze the impact of the microbiome on vaccine responses.

Probiotics in the next-generation sequencing era

Technological developments, including massively parallel DNA sequencing, gnotobiotics, metabolomics, RNA sequencing and culturomics, have markedly propelled the field of microbiome research in recent years. These methodologies can be harnessed to improve our in-depth mechanistic understanding of basic concepts related to consumption of probiotics, including their rules of engagement with the indigenous microbiome and impacts on the human host. We have recently demonstrated that even during probiotic supplementation, resident gut bacteria in a subset of individuals resist the mucosal presence of probiotic strains, limiting their modulatory effect on the microbiome and on the host gut transcriptional landscape. Resistance is partly alleviated by antibiotics treatment, which enables probiotics to interact with the host at the gut mucosal interface, although rather than promoting reconstitution of the indigenous microbiome and of the host transcriptional profile, they inhibit these components from returning to their naïve pre-antibiotic configurations. In this commentary, we discuss our findings in the context of previous and recent works, and suggest that incorporating the state-of-the-art methods currently utilized in microbiome research into the field of probiotics may lead to improved understanding of their mechanisms of activity, as well as their efficacy and long-term safety.

Mechanisms of Action of Probiotics

Probiotics are living microorganisms that confer health benefits to the host when administered in adequate amounts; however, dead bacteria and their components can also exhibit probiotic properties. Bifidobacterium and strains of lactic acid bacteria are the most widely used bacteria that exhibit probiotic properties and are included in many functional foods and dietary supplements. Probiotics have been shown to prevent and ameliorate the course of digestive disorders such as acute, nosocomial, and antibiotic-associated diarrhea; allergic disorders such as atopic dermatitis (eczema) and allergic rhinitis in infants; and Clostridium difficile-associated diarrhea and some inflammatory bowel disorders in adults. In addition, probiotics may be of interest as coadjuvants in the treatment of metabolic disorders, including obesity, metabolic syndrome, nonalcoholic fatty liver disease, and type 2 diabetes. However, the mechanisms of action of probiotics, which are diverse, heterogeneous, and strain specific, have received little attention. Thus, the aim of the present work was to review the main mechanisms of action of probiotics, including colonization and normalization of perturbed intestinal microbial communities in children and adults; competitive exclusion of pathogens and bacteriocin production; modulation of fecal enzymatic activities associated with the metabolization of biliary salts and inactivation of carcinogens and other xenobiotics; production of short-chain and branched-chain fatty acids, which, in turn, have wide effects not only in the intestine but also in peripheral tissues via interactions with short-chain fatty acid receptors, modulating mainly tissue insulin sensitivity; cell adhesion and mucin production; modulation of the immune system, which results mainly in the differentiation of T-regulatory cells and upregulation of anti-inflammatory cytokines and growth factors, i.e., interleukin-10 and transforming growth factor; and interaction with the brain-gut axis by regulation of endocrine and neurologic functions. Further research to elucidate the precise molecular mechanisms of action of probiotics is warranted.

The Role of Succinate in the Regulation of Intestinal Inflammation

Succinate is a metabolic intermediate of the tricarboxylic acid (TCA) cycle within host cells. Succinate is also produced in large amounts during bacterial fermentation of dietary fiber. Elevated succinate levels within the gut lumen have been reported in association with microbiome disturbances (dysbiosis), as well as in patients with inflammatory bowel disease (IBD) and animal models of intestinal inflammation. Recent studies indicate that succinate can activate immune cells via its specific surface receptor, succinate receptor 1(SUCNR1), and enhance inflammation. However, the role of succinate in inflammatory processes within the gut mucosal immune system is unclear. This review includes current literature on the association of succinate with intestinal inflammation and the potential role of succinate–SUCNR1 signaling in gut immune functions.

Lactobacillus plantarum 299v Reduces the Incidence of Clostridium difficile Infection in Nephrology and Transplantation Ward-Results of One Year Extended Study

Background: Lactobacillus plantarum 299v (LP299v) is a probiotic strain which influences on the intestinal bacterial flora. This is why, it has been introduced into clinical practice for the prevention and treatment of diarrheal disorders and alleviation of their symptoms in patients during antibiotic therapy. However, the use of probiotics in the prophylaxis of Clostridium difficile infections (CDI) in these patients is problematic. The aim of this clinical, retrospective, single-centre study was to analyse the incidence of CDI among patients hospitalized in the nephrology and transplantation ward in the period before, during and after stopping of LP299v prophylaxis. Methods: Among 5341 patients hospitalized in the nephrology and transplantation ward over a three year period, 34 patients with CDI were diagnosed and included in this analysis. From December 2013 to December 2014 all patients under antibiotic and immunosuppressive therapies received LP299v as a prophylaxis of CDI. The observation period consisted of three twelve-months periods: before, during LP299v use and after stopping of such method of CDI prevention. Results: A significant (p = 0.0003) reduction of CDI incidence during LP299v use (0.11%) was observed compared to two other periods, that is, before and after LP299v use (1.03% and 0.77%, respectively). Conclusions: Routine use of LP299v as a CDI prophylaxis may prevent CDI during antibiotics therapy in patients treated with immunosuppressive agents in nephrology and transplantation ward.

Effectiveness of probiotics in reducing the incidence of Clostridium difficile-associated diarrhea in elderly patients: a systematic review

BACKGROUND

Clostridium difficile bacteria are a leading cause of infectious diarrhea. This is an anaerobic, gram-positive and spore-forming rod responsible for significant morbidity and mortality, especially among elderly hospitalized patients. Standard management of C. difficile-associated diarrhea (CDAD) consists of discontinuing a causative antibiotic, correcting fluid-electrolytes imbalance and initiating an antibiotic treatment for CDAD. Alternative approaches for prevention of CDAD include probiotics. This systematic review will provide a comprehensive, unbiased summary of the available research on the effectiveness of probiotics in decreasing the incidence of infectious diarrhea in elderly hospitalized patients.

OBJECTIVES

To conduct a systematic review to determine the best available evidence related to the effectiveness of probiotics in the prevention of CDAD in elderly hospitalized patients. The review question was: are probiotics effective in decreasing the incidence of CDAD in elderly hospitalized patients?

INCLUSION CRITERIA TYPES OF PARTICIPANTS

The current review included studies of participants who were aged 60 years and more and who were residents of acute- and post-acute care facilities undergoing or planning to undergo antibiotic treatment for the management of any infectious conditions, except CDAD.

TYPES OF INTERVENTION(S)

The current review included studies that evaluated the effectiveness of probiotics for prevention of CDAD in elderly hospitalized patients in acute- and post-acute care settings compared to usual care.

OUTCOMES

The current review included studies examining the following outcome measures: incidence or relapse of CDAD. Cases of CDAD were defined by presence of diarrhea and verified by positive results for stool enzyme immunoassay for toxins A and B.

TYPES OF STUDIES

The current review included only experimental study designs including randomized controlled trials.

SEARCH STRATEGY

The search strategy included studies published in English between 1978, when the first case of CDAD was reported, and 2015.

ASSESSMENT OF METHODOLOGICAL QUALITY

Papers selected for retrieval were assessed by two independent reviewers for methodological quality prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute (JBI).

DATA EXTRACTION

Data were extracted from papers included in the review using the standardized data extraction tool from the JBI Meta-Analysis of Statistics Assessment and Review Instrument. The data extracted included specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives.

DATA SYNTHESIS

Quantitative data were pooled using statistical meta-analysis. Effect sizes were expressed as odds ratios, and their 95% confidence intervals were calculated to determine if probiotic treatment was superior to placebo in reducing CDAD incidence. Heterogeneity was assessed using the standard I statistic.

RESULTS

Five studies were included in the review. The individual study results were conflicting, including non-significant results for four studies and statistically significant results in one that demonstrated fewer cases of CDAD among patients receiving probiotics compared to placebo. The meta-analysis finding indicated that there was no statistically significant difference in CDAD incidence in elderly hospitalized patients taking probiotics when compared to a placebo.

CONCLUSION

Probiotics were not found to be more effective than placebo for reducing CDAD incidence in elderly hospitalized patients. However, studies that demonstrate improved outcomes must be examined to determine future needs for research. Studies varied with regard to the dose, frequency, method of administration (probiotic drinks versus capsule), length of administration and the number of strains of bacteria administered. Further studies are needed to evaluate the effectiveness of probiotics for CDAD prevention in this population. Clinical trials with evidence-based administration methods and meta-analyses that pool the results of studies with congruent methodologies are needed to enable conclusions to be drawn on the effectiveness of probiotic administration for CDAD prevention.

Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children

BACKGROUND

Antibiotics can disturb gastrointestinal microbiota which may lead to reduced resistance to pathogens such as Clostridium difficile (C. difficile). Probiotics are live microbial preparations that, when administered in adequate amounts, may confer a health benefit to the host, and are a potential C. difficile prevention strategy. Recent clinical practice guidelines do not recommend probiotic prophylaxis, even though probiotics have the highest quality evidence among cited prophylactic therapies.

OBJECTIVES

To assess the efficacy and safety of probiotics for preventing C.difficile-associated diarrhea (CDAD) in adults and children.

SEARCH METHODS

We searched PubMed, EMBASE, CENTRAL, and the Cochrane IBD Group Specialized Register from inception to 21 March 2017. Additionally, we conducted an extensive grey literature search.

SELECTION CRITERIA

Randomized controlled (placebo, alternative prophylaxis, or no treatment control) trials investigating probiotics (any strain, any dose) for prevention of CDAD, or C. difficile infection were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors (independently and in duplicate) extracted data and assessed risk of bias. The primary outcome was the incidence of CDAD. Secondary outcomes included detection of C. difficile infection in stool, adverse events, antibiotic-associated diarrhea (AAD) and length of hospital stay. Dichotomous outcomes (e.g. incidence of CDAD) were pooled using a random-effects model to calculate the risk ratio (RR) and corresponding 95% confidence interval (95% CI). We calculated the number needed to treat for an additional beneficial outcome (NNTB) where appropriate. Continuous outcomes (e.g. length of hospital stay) were pooled using a random-effects model to calculate the mean difference and corresponding 95% CI. Sensitivity analyses were conducted to explore the impact of missing data on efficacy and safety outcomes. For the sensitivity analyses, we assumed that the event rate for those participants in the control group who had missing data was the same as the event rate for those participants in the control group who were successfully followed. For the probiotic group, we calculated effects using the following assumed ratios of event rates in those with missing data in comparison to those successfully followed: 1.5:1, 2:1, 3:1, and 5:1. To explore possible explanations for heterogeneity, a priori subgroup analyses were conducted on probiotic species, dose, adult versus pediatric population, and risk of bias as well as a post hoc subgroup analysis on baseline risk of CDAD (low 0% to 2%; moderate 3% to 5%; high > 5%). The overall quality of the evidence supporting each outcome was independently assessed using the GRADE criteria.

MAIN RESULTS

Thirty-nine studies (9955 participants) met the eligibility requirements for our review. Overall, 27 studies were rated as either high or unclear risk of bias. A complete case analysis (i.e. participants who completed the study) among trials investigating CDAD (31 trials, 8672 participants) suggests that probiotics reduce the risk of CDAD by 60%. The incidence of CDAD was 1.5% (70/4525) in the probiotic group compared to 4.0% (164/4147) in the placebo or no treatment control group (RR 0.40, 95% CI 0.30 to 0.52; GRADE = moderate). Twenty-two of 31 trials had missing CDAD data ranging from 2% to 45%. Our complete case CDAD results proved robust to sensitivity analyses of plausible and worst-plausible assumptions regarding missing outcome data and results were similar whether considering subgroups of trials in adults versus children, inpatients versus outpatients, different probiotic species, lower versus higher doses of probiotics, or studies at high versus low risk of bias. However, in a post hoc analysis, we did observe a subgroup effect with respect to baseline risk of developing CDAD. Trials with a baseline CDAD risk of 0% to 2% and 3% to 5% did not show any difference in risk but trials enrolling participants with a baseline risk of > 5% for developing CDAD demonstrated a large 70% risk reduction (interaction P value = 0.01). Among studies with a baseline risk > 5%, the incidence of CDAD in the probiotic group was 3.1% (43/1370) compared to 11.6% (126/1084) in the control group (13 trials, 2454 participants; RR 0.30, 95% CI 0.21 to 0.42; GRADE = moderate). With respect to detection of C. difficile in the stool pooled complete case results from 15 trials (1214 participants) did not show a reduction in infection rates. C. difficile infection was 15.5% (98/633) in the probiotics group compared to 17.0% (99/581) in the placebo or no treatment control group (RR 0.86, 95% CI 0.67 to 1.10; GRADE = moderate). Adverse events were assessed in 32 studies (8305 participants) and our pooled complete case analysis indicates probiotics reduce the risk of adverse events by 17% (RR 0.83, 95% CI 0.71 to 0.97; GRADE = very low). In both treatment and control groups the most common adverse events included abdominal cramping, nausea, fever, soft stools, flatulence, and taste disturbance.

AUTHORS' CONCLUSIONS

Based on this systematic review and meta-analysis of 31 randomized controlled trials including 8672 patients, moderate certainty evidence suggests that probiotics are effective for preventing CDAD (NNTB = 42 patients, 95% CI 32 to 58). Our post hoc subgroup analyses to explore heterogeneity indicated that probiotics are effective among trials with a CDAD baseline risk >5% (NNTB = 12; moderate certainty evidence), but not among trials with a baseline risk ≤5% (low to moderate certainty evidence). Although adverse effects were reported among 32 included trials, there were more adverse events among patients in the control groups. The short-term use of probiotics appears to be safe and effective when used along with antibiotics in patients who are not immunocompromised or severely debilitated. Despite the need for further research, hospitalized patients, particularly those at high risk of CDAD, should be informed of the potential benefits and harms of probiotics.

Analysis of short-chain fatty acids in human feces: A scoping review

Short-chain fatty acids (SCFAs) play a crucial role in maintaining homeostasis in humans, therefore the importance of a good and reliable SCFAs analytical detection has raised a lot in the past few years. The aim of this scoping review is to show the trends in the development of different methods of SCFAs analysis in feces, based on the literature published in the last eleven years in all major indexing databases. The search criteria included analytical quantification techniques of SCFAs in different human clinical and in vivo studies. SCFAs analysis is still predominantly performed using gas chromatography (GC), followed by high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) and capillary electrophoresis (CE). Performances, drawbacks and advantages of these methods are discussed, especially in the light of choosing a proper pretreatment, as feces is a complex biological material. Further optimization to develop a simple, cost effective and robust method for routine use is needed.

Lactobacillus plantarum NCU116 attenuates cyclophosphamide-induced intestinal mucosal injury, metabolism and intestinal microbiota disorders in mice

Anticancer drugs at high doses often damage the intestinal mucosa and metabolism. Lactobacillus plantarum NCU116 (NCU116) isolated from pickled vegetables was orally given to cyclophosphamide-treated mice to determine its effects on intestinal mucosal injury, nutrient metabolism and colon microbiota, and investigate the mechanisms accounting for its effects. Mice treated with the bacterium were found to favorably recover intestine morphology of villus height and crypt depth, and have improved mucins expression and quantity of goblet cells, as well as intestinal metabolism by increasing the level of short-chain fatty acids and reducing the concentration of ammonia in the colon feces. In addition, NCU116-treated mice showed a higher diversity of colonic microbiota than the group without bacterium supplementation. The number of Lactobacillus and Bifidobacterium in the mouse colon was increased after bacterium intake, which decreased the number of potentially pathogenic bacteria, Escherichia coli and Pseudomonas. These results indicated that NCU116 could be of significant advantage in reducing intestinal mucosal injury and improving the intestinal metabolism and the intestinal microbiota.

The Effect of Lactobacillus plantarum 299v on the Incidence of Clostridium difficile Infection in High Risk Patients Treated with Antibiotics

Background:Lactobacillus plantarum 299v (LP299v) has been used in order to reduce gastrointestinal symptoms during antibiotic exposure. However, it remains controversial whether or not probiotics are effective in the prevention of Clostridium difficile infections (CDI) among patients receiving antibiotics. The aim of this study was to analyze the CDI among patients receiving antibiotics and hospitalized in the period before and after starting routine use of LP299v as a prevention of this infection. Methods: Among 3533 patients hospitalized in the nephrology and transplantation ward during a two-year period, 23 patients with CDI were diagnosed and enrolled in this retrospective study. Since November 2013, prevention of CDI with oral use of LP299v was performed in all patients treated with antibiotics and who were at a high risk of developing CDI. The observation period was divided into two twelve-month intervals before and after initiation of the use of LP299v as a prophylactic against CDI. Results: A significant (p = 0.0001) reduction of the number of cases of CDI was found after routinely using LP299v (n = 2; 0.11% of all hospitalized patients) compared with the previous twelve-month period of observation (n = 21; 1.21% of all hospitalized patients). Conclusions: Routine use of LP299v during treatment with antibiotics may prevent C. difficile infection in the nephrology and transplantation ward.

The safety and feasibility of probiotics in children and adolescents undergoing hematopoietic cell transplantation

Hematopoietic cell transplantation (HCT) has become a standard treatment for many adult and pediatric conditions. Emerging evidence suggests that perturbations in the microbiota diversity increase recipients' susceptibilities to gut-mediated conditions such as diarrhea, infection and acute GvHD. Probiotics preserve the microbiota and may minimize the risk of developing a gut-mediated condition; however, their safety has not been evaluated in the setting of HCT. We evaluated the safety and feasibility of the probiotic, Lactobacillus plantarum (LBP), in children and adolescents undergoing allogeneic HCT. Participants received once-daily supplementation with LBP beginning on day -8 or -7 and continued until day +14. Outcomes were compliance with daily administration and incidence of LBP bacteremia. Administration of LBP was feasible with 97% (30/31, 95% confidence interval (CI) 83-100%) of children receiving at least 50% of the probiotic dose (median 97%; range 50-100%). We did not observe any case of LBP bacteremia (0% (0/30) with 95% CI 0-12%). There were not any unexpected adverse events related to LBP. Our study provides preliminary evidence that administration of LBP is safe and feasible in children and adolescents undergoing HCT. Future steps include the conduct of an approved randomized, controlled trial through Children's Oncology Group.

The microbiome and regulation of mucosal immunity

The gastrointestinal tract is a mucosal surface constantly exposed to foreign antigens and microbes, and is protected by a vast array of immunologically active structures and cells. Epithelial cells directly participate in immunological surveillance and direction of host responses in the gut and can express numerous pattern recognition receptors, including Toll-like receptor 5 (TLR5), TLR1, TLR2, TLR3, TLR9, and nucleotide oligomerization domain 2, as well as produce chemotactic factors for both myeloid and lymphoid cells following inflammatory stimulation. Within the epithelium and in the underlying lamina propria resides a population of innate lymphoid cells that, following stimulation, can become activated and produce effector cytokines and exert both protective and pathogenic roles during inflammation. Lamina propria dendritic cells play a large role in determining whether the response to a particular antigen will be inflammatory or anti-inflammatory. It is becoming clear that the composition and metabolic activity of the intestinal microbiome, as a whole community, exerts a profound influence on mucosal immune regulation. The microbiome produces short-chain fatty acids, polysaccharide A, α-galactosylceramide and tryptophan metabolites, which can induce interleukin-22, Reg3γ, IgA and interleukin-17 responses. However, much of what is known about microbiome-host immune interactions has come from the study of single bacterial members of the gastrointestinal microbiome and their impact on intestinal mucosal immunity. Additionally, evidence continues to accumulate that alterations of the intestinal microbiome can impact not only gastrointestinal immunity but also immune regulation at distal mucosal sites.

Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children

BACKGROUND

Antibiotics are widely prescribed; however they can cause disturbances in gastrointestinal flora which may lead to reduced resistance to pathogens such as Clostridium difficile (C. difficile). Probiotics are live organisms thought to balance the gastrointestinal flora.

OBJECTIVES

The primary objectives were to assess the efficacy and safety of probiotics for preventing Clostridium difficile-associated diarrhea (CDAD) or C. difficile infection in adults and children.

SEARCH METHODS

On February 21, 2013 we searched PubMed (1966-2013), EMBASE (1966-2013), Cochrane Central Register of Controlled Trials (The Cochrane Library 2013, Issue 1), CINAHL (1982-2013), AMED (1985-2013), and ISI Web of Science. Additionally, we conducted an extensive grey literature search including contact with industry representatives.

SELECTION CRITERIA

Randomized controlled (placebo, alternative prophylaxis, or no treatment control) trials investigating probiotics (any strain, any dose) for prevention of CDAD, or C. difficile infection were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently and in duplicate extracted data and assessed risk of bias using pre-constructed, and piloted, data extraction forms. Any disagreements were resolved by a third adjudicator. For articles published in abstract form only, further information was sought by contacting principal authors. The primary outcome was the incidence of CDAD. Secondary outcomes included the incidence of C. difficile infection, adverse events, antibiotic-associated diarrhea (AAD) and length of hospital stay. Dichotomous outcomes (e.g. incidence of CDAD) were pooled using a random-effects model to calculate the relative risk and corresponding 95% confidence interval (95% CI). Continuous outcomes (e.g. length of hospital) were pooled using a random-effects model to calculate the mean difference and corresponding 95% CI. Sensitivity analyses were conducted to explore the impact of missing data on efficacy and safety outcomes. For the sensitivity analyses, we assumed that the event rate for those participants in the control group who had missing data was the same as the event rate for those participants in the control group who were successfully followed. For the probiotic group we calculated effects using the following assumed ratios of event rates in those with missing data in comparison to those successfully followed: 1.5:1, 2:1, 3:1, and 5:1. To explore possible explanations for heterogeneity, a priori subgroup analysis were conducted on probiotic species, dose, adult versus pediatric population, and risk of bias.The overall quality of the evidence supporting each outcome was assessed using the GRADE criteria.

MAIN RESULTS

A total of 1871 studies were identified with 31 (4492 participants) meeting eligibility requirements for our review. Overall 11 studies were rated as a high risk of bias due mostly to missing outcome data. A complete case analysis (i.e. participants who completed the study) of those trials investigating CDAD (23 trials, 4213 participants) suggests that probiotics significantly reduce this risk by 64%. The incidence of CDAD was 2.0% in the probiotic group compared to 5.5% in the placebo or no treatment control group (RR 0.36; 95% CI 0.26 to 0.51). Sixteen of 23 trials had missing CDAD data ranging from 5% to 45%. These results proved robust to sensitivity analyses of plausible and worst-plausible assumptions regarding missing outcome data and were similar whether considering trials in adults versus children, lower versus higher doses, different probiotic species, or higher versus lower risk of bias. Our judgment is that the overall evidence warrants moderate confidence in this large relative risk reduction. We downgraded the overall quality of evidence for CDAD to 'moderate' due to imprecision. There were few events (154) and the calculated optimal information size (n = 8218) was more than the total sample size. With respect to the incidence of C. difficile infection, a secondary outcome, pooled complete case results from 13 trials (961 participants) did not show a statistically significant reduction. The incidence of C. difficile infection was 12.6% in the probiotics group compared to 12.7% in the placebo or no treatment control group (RR 0.89; 95% CI 0.64 to 1.24). Adverse events were assessed in 26 studies (3964 participants) and our pooled complete case analysis indicates probiotics reduce the risk of adverse events by 20% (RR 0.80; 95% CI 0.68 to 0.95). In both treatment and control groups the most common adverse events included abdominal cramping, nausea, fever, soft stools, flatulence, and taste disturbance. For the short-term use of probiotics in patients that are not immunocompromised or severely debilitated, we consider the strength of this evidence to be moderate.

AUTHORS' CONCLUSIONS

Based on this systematic review and meta-analysis of 23 randomized controlled trials including 4213 patients, moderate quality evidence suggests that probiotics are both safe and effective for preventing Clostridium difficile-associated diarrhea.

Probiotics, prebiotics infant formula use in preterm or low birth weight infants: a systematic review

BACKGROUND

Previous reviews (2005 to 2009) on preterm infants given probiotics or prebiotics with breast milk or mixed feeds focused on prevention of Necrotizing Enterocolitis, sepsis and diarrhea. This review assessed if probiotics, prebiotics led to improved growth and clinical outcomes in formula fed preterm infants.

METHODS

Cochrane methodology was followed using randomized controlled trials (RCTs) which compared preterm formula containing probiotic(s) or prebiotic(s) to conventional preterm formula in preterm infants. The mean difference (MD) and corresponding 95% confidence intervals (CI) were reported for continuous outcomes, risk ratio (RR) and corresponding 95% CI for dichotomous outcomes. Heterogeneity was assessed by visual inspection of forest plots and a chi² test. An I² test assessed inconsistencies across studies. I²> 50% represented substantial heterogeneity.

RESULTS

Four probiotics studies (N=212), 4 prebiotics studies (N=126) were included. Probiotics: There were no significant differences in weight gain (MD 1.96, 95% CI: -2.64 to 6.56, 2 studies, n=34) or in maximal enteral feed (MD 35.20, 95% CI: -7.61 to 78.02, 2 studies, n=34), number of stools per day increased significantly in probiotic group (MD 1.60, 95% CI: 1.20 to 2.00, 1 study, n=20). Prebiotics: Galacto-oligosaccharide/Fructo-oligosaccharide (GOS/FOS) yielded no significant difference in weight gain (MD 0.04, 95% CI: -2.65 to 2.73, 2 studies, n=50), GOS/FOS yielded no significant differences in length gain (MD 0.01, 95% CI: -0.03 to 0.04, 2 studies, n=50). There were no significant differences in head growth (MD -0.01, 95% CI: -0.02 to 0.00, 2 studies, n=76) or age at full enteral feed (MD -0.79, 95% CI: -2.20 to 0.61, 2 studies, n=86). Stool frequency increased significantly in prebiotic group (MD 0.80, 95% CI: 0.48 to 1.1, 2 studies, n=86). GOS/FOS and FOS yielded higher bifidobacteria counts in prebiotics group (MD 2.10, 95% CI: 0.96 to 3.24, n=27) and (MD 0.48, 95% CI: 0.28 to 0.68, n=56).

CONCLUSIONS

There is not enough evidence to state that supplementation with probiotics or prebiotics results in improved growth and clinical outcomes in exclusively formula fed preterm infants.

Intake of Lactobacillus plantarum reduces certain gastrointestinal symptoms during treatment with antibiotics

GOALS

To examine if intake of Lactobacillus plantarum can prevent gastrointestinal side effects in antibiotic-treated patients.

BACKGROUND

Diarrhea is a common side effect of treatment with antibiotics. Some studies indicate that the risk of antibiotic-associated diarrhea can be reduced by administration of certain probiotic microorganisms.

STUDY

Patients treated for infections at a university hospital infectious diseases clinic were randomized to daily intake of either a fruit drink with L. plantarum 299v (10(10) colony forming units/d) or a placebo drink, until a week after termination of antibiotic treatment. Subjects recorded the number and consistency of stools as well as gastrointestinal symptoms until up to 3 weeks after last intake of test drink. Fecal samples were collected before the first intake of test drink and after termination of antibiotic therapy and analyzed for Clostridium difficile toxin.

RESULTS

Clinical characteristics on admission were similar in the 2 groups. The overall risk of developing loose or watery stools was significantly lower among those receiving L. plantarum [odds ratio (OR), 0.69; 95% confidence interval (CI), 0.52-0.92; P=0.012], as was development of nausea (OR, 0.51; 95% CI, 0.30-0.85; P=0.0097). Diarrhea defined as > or =3 loose stools/24 h for > or =2 consecutive days was unaffected by the treatment (OR, 1.4; 95% CI, 0.33-6.0; P=0.86). No significant differences regarding carriage of toxin producing C. difficile were observed between the groups.

CONCLUSIONS

Our results indicate that intake of L. plantarum could have a preventive effect on milder gastrointestinal symptoms during treatment with antibiotics.

Safety and tolerance of the human milk probiotic strain Lactobacillus salivarius CECT5713 in 6-month-old children

OBJECTIVE

Intestinal microbiota plays an important role in the prevention of certain diseases during the pediatric years. Thus, there is an increasing interest in the addition of probiotics to infant formulas. The aim of this study was to evaluate the safety of a follow-on formula with Lactobacillus salivarius CECT5713 in 6-mo-old children.

METHODS

The antibiotic susceptibility of L. salivarius CECT5713 was analyzed by a dilution method. A double-blinded, randomized, placebo controlled study was performed. Children (n = 80) were distributed in two groups and consumed the formula supplemented or not with probiotics (2 × 10(6) colony-forming units [cfu]/g) during 6 mo. Fecal samples were collected at enrollment, at 3 mo, and at the end of trial. Clinical and anthropometric evaluations were performed. Depending on the variable, one-way or two-way repeated measures analysis of variance were used for the statistical analysis.

RESULTS

The antibiotic susceptibility profile of the strain resulted as safe. No adverse effects associated with the consumption of the probiotic formula were reported. In addition, clinical parameters did not differ between groups. Consumption of the probiotic supplemented formula led to an increase in the fecal lactobacilli content (7.6 ± 0.2 versus 7.9 ± 0.1 log cfu/g, P < 0.05). Lactobacillus salivarius CECT5713 was detected in the feces of volunteers from the probiotic group. Probiotic consumption induced a significant increase in the fecal concentration of butyric acid at 6 mo.

CONCLUSION

Thus, a follow-on formula with L. salivarius CECT5713 is safe and well tolerated in 6-mo-old infants.

A human, double-blind, placebo-controlled, crossover trial of prebiotic, probiotic, and synbiotic supplementation: effects on luminal, inflammatory, epigenetic, and epithelial biomarkers of colorectal cancer

BACKGROUND

Diet is an important factor in colorectal carcinogenesis; thus, dietary supplements may have a role in colorectal cancer prevention.

OBJECTIVE

The objective was to establish the relative luminal, epithelial, and epigenetic consequences of prebiotic, probiotic, and synbiotic dietary supplementation in humans.

DESIGN

This was a randomized, double-blind, placebo-controlled, 4-wk crossover trial of resistant starch and Bifidobacterium lactis, either alone or as a combined synbiotic preparation, in 20 human volunteers. Rectal biopsy, feces, and serum samples were collected. The rectal mucosal endpoints were DNA methylation at 16 CpG island loci and LINE-1, epithelial proliferation (Ki67 immunohistochemistry), and crypt cellularity. The fecal endpoints were short-chain fatty acid concentrations, pH, ammonia, and microbiological profiles (by denaturing gradient gel electrophoresis and sequencing). Serum endpoints were a panel of cytokines and high-sensitivity C-reactive protein.

RESULTS

Seventeen subjects completed the entire study. The synbiotic intervention fostered a significantly different fecal stream bacterial community than did either the prebiotic (P = 0.032) or the probiotic (P = 0.001) intervention alone, in part because of a greater proportion of patients harboring fecal Lachnospiraceae spp. These changes developed in the absence of any significant differences in fecal chemistry. There were no differences in epithelial kinetics.

CONCLUSIONS

This synbiotic supplementation with B. lactis and resistant starch, in the doses used, induced unique changes in fecal microflora but did not significantly alter any other fecal, serum, or epithelial variables. This trial was registered in the Australian New Zealand Clinical Trials Registry at www.anzctr.org.au as ACTRN012606000115538.