Reuteri DSM Research Articles

1135 - Remodeling Gut Microbiota by Lactobacillus Reuteri DSM 17938 Suppresses Autoimmunity Induced by Treg Deficiency

1135 - Remodeling Gut Microbiota by Lactobacillus Reuteri DSM 17938 Suppresses Autoimmunity Induced by Treg Deficiency

Metabolic effects of Lactobacillus reuteri DSM 17938 in people with type 2 diabetes: A randomized controlled trial.

To investigate the metabolic effects of 12-week oral supplementation with Lactobacillus reuteri DSM 17938 in patients with type 2 diabetes on insulin therapy. In a double-blind trial, we randomized 46 people with type 2 diabetes to placebo or a low (108 CFU/d) or high dose (1010 CFU/d) of L. reuteri DSM 17938 for 12 weeks. The primary endpoint was the effect of supplementation on glycated haemoglobin (HbA1c). Secondary endpoints were insulin sensitivity (assessed by glucose clamp), liver fat content, body composition, body fat distribution, faecal microbiota composition and serum bile acids. Supplementation with L. reuteri DSM 17938 for 12 weeks did not affect HbA1c, liver steatosis, adiposity or microbiota composition. Participants who received the highest dose of L. reuteri exhibited increases in insulin sensitivity index (ISI) and serum levels of the secondary bile acid deoxycholic acid (DCA) compared with baseline, but these differences were not significant in the between-group analyses. Post hoc analysis showed that participants who responded with increased ISI after L. reuteri supplementation had higher microbial diversity at baseline, and increased serum levels of DCA after supplementation. In addition, increases in DCA levels correlated with improvement in insulin sensitivity in the probiotic recipients. Intake of L. reuteri DSM 17938 for 12 weeks did not affect HbA1c in people with type 2 diabetes on insulin therapy; however, L. reuteri improved insulin sensitivity in a subset of participants and we propose that high diversity of the gut microbiota at baseline may be important.

Stereoselective Chemoenzymatic Synthesis of Optically Active Aryl-Substituted Oxygen-Containing Heterocycles

A two-step stereoselective chemoenzymatic synthesis of optically active α-aryl-substituted oxygen heterocycles was developed, exploiting a whole-cell mediated asymmetric reduction of α-, β-, and γ-chloroalkyl arylketones followed by a stereospecific cyclization of the corresponding chlorohydrins into the target heterocycles. Among the various whole cells screened (baker’s yeast, Kluyveromyces marxianus CBS 6556, Saccharomyces cerevisiae CBS 7336, Lactobacillus reuteri DSM 20016), baker’s yeast was the one providing the best yields and the highest enantiomeric ratios (up to 95:5 er) in the bioreduction of the above ketones. The obtained optically active chlorohydrins could be almost quantitatively cyclized in a basic medium into the corresponding α-aryl-substituted cyclic ethers without any erosion of their enantiomeric integrity. In this respect, valuable, chiral non-racemic functionalized oxygen containing heterocycles (e.g., (S)-styrene oxide, (S)-2-phenyloxetane, (S)-2-phenyltetrahydrofuran), amenable to be further elaborated on, can be smoothly and successfully generated from their prochiral precursors.

Isothermal microcalorimetry for rapid viability assessment of freeze-dried Lactobacillus reuteri

Abstract The rapid assessment of viable cells in freeze-dried formulations of probiotic Lactobacilli is an important issue in the probiotic industry. The probiotic Lactobacillus reuteri DSM 17938 is the active ingredient of BioGaia Protectis whose viable cell concentrations are currently determined using the classical and time-consuming viable count technique. In this paper we present a rapid method based on Isothermal microcalorimetry (IMC) for viability assessment of freeze-dried DSM 17938. Fresh and rehydrated freeze-dried cells were incubated in MRS medium at different cell concentration and the thermal power (μW) at 37 °C was measured over time. A linear dependence between the time to reach a certain thermal power value and the decimal logarithm of viable cells was found. This allowed rapid viability assessment of rehydrated cells, reducing the detection time from 48 h (viable count) to 10 h (microcalorimetry) in samples with 3 × 103 cfu/mL, and to 4 h in samples with 4 × 106 cfu/mL. No significant differences were found between the two methods when freeze-dried rehydrated cells were analysed (p > 0.05). Therefore, IMC is a promising tool to be used in the quality control of freeze-dried DSM 17938 as well as other bacteria-based products.

Lactobacillus reuteri DSM 17938 in the prevention of antibiotic-associated diarrhoea in children: protocol of a randomised controlled trial

IntroductionAdministration of some probiotics appears to reduce the risk of antibiotic-associated diarrhoea (AAD). The effects of probiotics are strain-specific, thus, the efficacy and safety of each probiotic strain should be...

Effect of Formula Containing Lactobacillus reuteri DSM 17938 on Fecal Microbiota of Infants Born by Cesarean-Section.

Microbiota modulation by probiotics in infants born by cesarean (C)-section is poorly understood. We aimed at assessing the response of C-section-delivered infant microbiota to a formula containing Lactobacillus reuteri Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSM) 17938 and comparing it with that of vaginally delivered infants. Infants delivered by C-section (C) and vaginally (V) were randomized to receive either control formula (CCt, n = 10; VCt, n = 10) or the same formula containing L reuteri (CLr, n = 11; VLr, n = 9) within 72 hours following birth. Stool samples were collected at 2 weeks and 4 months of age. Microbial DNA was extracted, amplified, and pyrosequenced. The phylogenetic profiles of the CLr, VCt, and VLr microbiota were not significantly different at any age but diverged from that of CCt at 2 weeks. Compared with VCt, CCt displayed lower Bifidobacterium and higher Enterobacter, unclassified Enterobacteriaceae, Enterococcus, Clostridium, and unclassified Clostridiaceae relative abundance at 2 weeks, as well as lower Collinsella and higher Enterococcus and Coprococcus abundance at 4 months. The level of most of these taxa was not significantly different between the CLr and the vaginal-delivery groups. Compared with VCt, the only difference observed in VLr microbiota was higher Lactobacillus at the 2 study ages and Coprococcus at 4 months. Our results show that a formula containing L reuteri DSM 17938 does not essentially alter the microbiota in vaginally born infants. In C-section-delivered infants, however, this strain seems to play the role of keystone species by modulating the early development of the microbiota toward the composition found after vaginal delivery.

INFLUENCE VIOLATIONS FORMATION OF INTESTINAL FLORA, INTESTINAL BARRIER FUNCTION IN NEWBORNS OF INFECTIOUS AND INFLAMMATORY DISEASES AND THE IMPORTANCE OF PROBIOTICS IN THEIR PREVENTION

The article presents of modern data on the role of probiotics in the development of mature digestive tract, the effect of probiotics in prevention of inflammatory and infectious diseases of the digestive tract in newborns, especially premature, frequency of necrotizing enterocolitis in premature infants, late neonatal sepsis.The discussed main factors of worsen or slow down the process of formation of physiological microbiocenosis in newborns. These sow modern evidence-based recommendations for the study of the practical aspects of the use of probiotic microorganisms in neonatal practice. The modern scheme of probiotic microorganisms in neonatal wards submitted. These evidence-based benefits of prophylactic use of L. Reuteri DSM 17938, L. Reuteri ATCC 55730 in reducing the frequency of food intolerance, death, development of necrotizing enterocolitis, late neonatal sepsis. The potential prospects highlights for studying the role of Bacillus clausii in the maturation of the immune system and promoting the formation of a physiological intestinal microbiota in infants.

Metabolism of heterocyclic aromatic amines (HAA) by Lactobacillus reuteri DSM 20016

Metabolism of heterocyclic aromatic amines (HAA) by Lactobacillus reuteri DSM 20016

Regular consumption of Lactobacillus reuteri‐containing lozenges reduces pregnancy gingivitis: an RCT

AimThis randomized controlled trial assessed the impact of Lactobacillus reuteri on pregnancy gingivitis in healthy women.Materials and MethodsForty‐five healthy women (24 test/21 placebo) with pregnancy gingivitis in the third trimester of pregnancy were enrolled. At baseline Gingival Index (GI) and Plaque Index (PlI) were assessed at the Ramfjord teeth and venous blood taken for TNF‐α analysis. Subsequently participants were randomly provided with lozenges to be consumed 2 × daily until birth (approx. 7 weeks) containing ≥108 CFU L. reuteri ATCC PTA 5289 and ≥108 CFU L. reuteri DSM 17938 (test) or being devoid of L. reuteri (placebo). Within 2 days after birth recording of GI, PlI and blood sampling were repeated.ResultsAt baseline, mean GI and mean PlI did not differ significantly between both groups. In the test group mean TNF‐α serum level was significantly (p < 0.02) lower than in the placebo group. At reevaluation, mean GI and mean PlI of the test group were both significantly (p < 0.0001) lower than in the placebo group. Mean TNF‐α serum level did no longer differ significantly between the groups.ConclusionsThe consumption of L. reuteri lozenges may be a useful adjunct in the control of pregnancy gingivitis.

Probiotic Lactobacilli Modulate Staphylococcus aureus-Induced Activation of Conventional and Unconventional T cells and NK Cells.

Lactobacilli are probiotic commensal bacteria and potent modulators of immunity. When present in the gut or supplemented as probiotics, they beneficially modulate ex vivo immune responsiveness. Further, factors derived from several lactobacilli strains act immune regulatory in vitro. In contrast, Staphylococcus aureus (S. aureus) is known to induce excessive T cell activation. In this study, we aimed to investigate S. aureus-induced activation of human mucosal-associated invariant T cells (MAIT cells), γδ T cells, NK cells, as well as of conventional CD4+ and CD8+ T cells in vitro. Further, we investigated if lactobacilli-derived factors could modulate their activation. PBMC were cultured with S. aureus 161:2 cell-free supernatants (CFS), staphylococcal enterotoxin A or CD3/CD28-beads alone, or in combination with Lactobacillus rhamnosus GG-CFS or Lactobacillus reuteri DSM 17938-CFS and activation of T and NK cells was evaluated. S. aureus-CFS induced IFN-γ and CD107a expression as well as proliferation. Costimulation with lactobacilli-CFS dampened lymphocyte-activation in all cell types analyzed. Preincubation with lactobacilli-CFS was enough to reduce subsequent activation, and the absence of APC or APC-derived IL-10 did not prevent lactobacilli-mediated dampening. Finally, lactate selectively dampened activation of unconventional T cells and NK cells. In summary, we show that molecules present in the lactobacilli-CFS are able to directly dampen in vitro activation of conventional and unconventional T cells and of NK cells. This study provides novel insights on the immune-modulatory nature of probiotic lactobacilli and suggests a role for lactobacilli in the modulation of induced T and NK cell activation.

Gut microbiota mediated benefits of barley kernel products on metabolism, gut hormones, and inflammatory markers as affected by co-ingestion of commercially available probiotics: a randomized controlled study in healthy subjects

Barley kernel based products have been shown to induce benefits on blood glucose regulation, cardio-metabolic risk markers and appetite regulating hormones in a time perspective of 11-16h after intake. The mechanisms have been assigned to gut fermentation of indigestible carbohydrates. The purpose of the present study was to evaluate if the modulatory effects of barley on markers of metabolic- and appetite regulation are affected by a dietary background including a mixture of commercially available probiotics. Barley kernel bread was included in the normal diet of 21 healthy subjects in two 4-day intervention periods; with (BB-pro) or without (BB) dietary supplement with a combination of probiotics (Bifidobacterium animalis DN-173 010, Lactobacillus reuteri DSM 17938, and Lactobacillus plantarum 299v). A white wheat flour based bread was included as a reference product (WWB-ref) in a separate 4-day bread intervention period. A cross-over design was applied concerning BB- and WWB-ref; the BB-pro intervention was last in the test sequence. The BB-pro intervention was preceded by 10 days priming with probiotics. The 4 day BB- and WWB-ref intervention periods included dietary supplementation with placebo, and the interventions were preceded with 10 days priming with the placebo. The day after each intervention period, blood samples were collected at fasting and postprandially after a standardized breakfast (0-210min) for determination of markers of glucose metabolism (blood glucose, serum (s-) insulin), inflammation (s-IL-6, s-IL-18, s-CRP, PAI-1), and concentrations of gut derived hormones involved in satiety and glucose homeostasis (plasma (p-) PYY, p-GLP-1) and intestinal barrier integrity (p-GLP-2). Breath hydrogen was determined as a marker of colonic fermentation. Four days intervention with BB, in comparison to WWB-ref, lowered blood glucose response after a subsequent standardized breakfast (0-210min, P<0.05). BB and BB-pro interventions increased p-GLP-1 (0-120min, P<0.05) and breath H2 (0-210min, P<0.05). BB-pro intervention, in comparison to BB and WWB-ref, increased levels of s-PAI-1 (P<0.05), and p-GLP-2 (0-210min, P<0.05) after the standardized breakfast. With the exception of increased p-GLP-2 and an unexpected increase in s-PAI-1 concentrations, co-ingestion of a mixture of probiotics did not affect the metabolic outcome of BB; neither positively nor importantly negatively. The study was registered at: ClinicalTrials.gov, register number NCT01718418 (www.clinicaltrials.gov/ct2/show/NCT01718418).

Probiotics for Irritable Bowel Syndrome

ABSTRACTPurpose of review:The purpose of this review was to summarize the evidence regarding probiotics treatment for pediatric IBS.Recent findings:The overall management of children with IBS should be tailored to the patient's specific symptoms and identifiable triggers. The four major therapeutic approaches include: pharmacologic, dietary, psychosocial, and complementary/alternative medicine interventions.Although there is limited evidence for efficacy of pharmacological therapies such as antispasmodics and anti‐diarrheals, these may have a role in severe cases. A Cochrane review concluded that only weak evidence exists regarding beneficial effects of pharmacological agents in providing relief from symptoms in functional abdominal pain (AP) in children. Role of antibiotics in treatment of children with IBS remains controversial. Various non‐pharmacologic treatments are available for pediatric IBS. In a recent systematic review including 24 studies some evidence was found indicating beneficial effects of partially hydrolyzed guar gum (PHGG), cognitive behavioral therapy, hypnotherapy, and probiotics (LGG and VSL#3).Few randomized clinical trials (RCTs) are available in children. A meta‐analysis including 9 trials which tested different probiotics as a treatment for Functional Gastrointestinal Disorders (FGIDs) in children and adolescents concluded that Lactobacillus GG, Lactobacillus reuteri DSM 17938 and VSL#3 significantly increased treatment success. We recently showed that, in children with IBS, a mixture of Bifidobacterium infantis M‐63®, breve M‐16V® and longum BB536® is safe and is associated with better AP control and improved quality of life when compared to placebo.Summary:Probiotics are emerging as new therapeutic tools in FGIDs, due to the recognition of the importance of gut microbiota in influencing brain‐gut interactions, and of the role played by intestinal infections in the genesis of AP‐FGIDs. Preclinical data suggest that changes in the gut microbiota can affect brain signaling systems related to pain and associated emotional behavior. Therefore, probiotics could play a relevant role in the management of FGIDs, by affecting the gut microbiota or by altering brain function and pain perception centrally.

Indications and Recommendations by Societies and Institutions for the Use of Probiotics and Prebiotics in Paediatric Functional Intestinal Disorders

ABSTRACTPurpose of review:To report the indications and/or recommendations by Societies and Institutions for the use of probiotics and prebiotics in functional intestinal disorders in childhood.Recent findings:A position by Societies and Institutions is available only for infant colic, irritable bowel syndrome and constipation. Supplementation with the probiotic L reuteri DSM 17938 in breastfed term infants with colic appears to be effective in reducing crying, while still debated is its role in the prevention of colic. Irritable bowel syndrome is a common disorder in children and at present no specific treatments are available; existing data show that although high‐quality studies are still needed, some evidence support the efficacy of LGG and VSL#3 in paediatric IBS. At present there is no evidence for the use of pre‐ or probiotics in childhood constipation.Summary:Probiotics in a near future may have a definite role is some FGIDs of infants and children. The main limitations for the recommendation by Societies and Institutions are the methodological issues that limit the quality of the evidence and the heterogeneity of treatments (probiotic strain and dose, mode, dose and duration of supplementation, primary outcomes, etc). Some specific strains are promising for infant colic (L. reuteri DSM 17938) and irritable bowel syndrome (LGG) while at present there is no indication for their use in the treatment of childhood constipation.

Lactobacillus reuteri DSM 17938 for the Management of Functional Abdominal Pain in Childhood: A Randomized, Double-Blind, Placebo-Controlled Trial

To determine whether administration of Lactobacillus reuteri DSM 17938 is beneficial in functional abdominal pain (FAP) of childhood. A total of 101 children, aged 6-15years, who fulfilled the Rome III criteria for FAP were enrolled in a randomized double-blind, placebo-controlled trial, and were randomly assigned to receive either L reuteri DSM 17938 or placebo for 4weeks, with further follow-up of additional 4weeks. Response to therapy was based on a self-reported daily questionnaire monitoring frequency and intensity of abdominal pain, using the faces scoring system by Hicks. L reuteri (n=47) was significantly superior to placebo (n=46) in relieving frequency (1.9±0.8 vs 3.6±1.7 episodes/wk, P<.02) and intensity (4.3±2.2 vs 7.2±3.1 Hicks score/wk, P<.01) of abdominal pain following 4weeks of supplementation. There was no difference in school absenteeism rate or other gastrointestinal symptoms, except for a lower incidence of perceived abdominal distention and bloating, favoring L reuteri. L reuteri DSM 17938, compared with placebo, significantly reduced the frequency and intensity of FAP in children. ClicalTrials.gov: NCT01180556.

Characterization of biosurfactants produced by Lactobacillus spp. and their activity against oral streptococci biofilm.

Lactic acid bacteria (LAB) can interfere with pathogens through different mechanisms; one is the production of biosurfactants, a group of surface-active molecules, which inhibit the growth of potential pathogens. In the present study, biosurfactants produced by Lactobacillus reuteri DSM 17938, Lactobacillus acidophilus DDS-1, Lactobacillus rhamnosus ATCC 53103, and Lactobacillus paracasei B21060 were dialyzed (1 and 6kDa) and characterized in term of reduction of surface tension and emulsifying activity. Then, aliquots of the different dialyzed biosurfactants were added to Streptococcus mutans ATCC 25175 and Streptococcus oralis ATCC 9811 in the culture medium during the formation of biofilm on titanium surface and the efficacy was determined by agar plate count, biomass analyses, and flow cytometry. Dialyzed biosurfactants showed abilities to reduce surface tension and to emulsifying paraffin oil. Moreover, they significantly inhibited the adhesion and biofilm formation on titanium surface of S. mutans and S. oralis in a dose-dependent way, as demonstrated by the remarkable decrease of cfu/ml values and biomass production. The antimicrobial properties observed for dialyzed biosurfactants produced by the tested lactobacilli opens future prospects for their use against microorganisms responsible of oral diseases.

The dynamics of the morphological status of the gastric mucosa in the early post-eradication period in children

Helicobacter pylori (Нр) in 60–80 % of cases is the cause of forming the gastric ulcer and in у 90–95 % – the duodenum ulcer, there was also proved its connection with appearance of adenocarcinomas and gastric lymph. But elimination of Нр does not lead to the stopping of inflammatory response of mucosa. The search for the ways of control of the mucosa inflammatory response along with eradication of Нр-infection is a topical problem of children gastroenterology.Aim of research was the study of influence of probiotic that contains Lactobacillus reuteri DSM 17938 on inflammatory changes of gastric mucosa in children with destructive forms of gastroduodenal zone pathology after successful eradication therapy.Materials and methods of research. There were examined 98 children 8–13 years old with destructive forms of gastroduodenal pathology. The verification of diagnosis and treatment was carried out according to the actual Ukrainian MHP protocols of giving help to the children with gastroduodenal pathology. Diagnostics of Нр was carried out using histological method and detection of Нр antigen in excrements. At morphological study of mucosa bioptats there were assessed the degree of intensity of the chronic inflammatory process, its activity, presence and intensity of mucosa atrophy and metaplasia. The main group (MG) included 53 children who received the eradication therapy from the very beginning and during the month after its end received preparations that contain Lactobacillus reuteri; the control group (CG) included 45 children who received an analogous treatment but probiotics were prescribed if necessary and only at the time of taking antibiotics.Results of research. The results of morphological studies in children from the MG demonstrated the considerably less intense inflammatory changes of mucosa than in children from the CG. Especially the degree of inflammatory process severity and activity were statistically reliably lower in MG comparing with CG. The part of patients with the symptoms of mucosa atrophy decreased more essentially in MG but the difference was not reliable.Conclusions. After elimination of Нр in children the inflammatory changes of gastric mucosa that can be the cause of the further mucosa lesion remain stable. Prescription of probiotics that include Lactobacillus reuteri DSM 17938 resulted in decrease of inflammatory changes and it can be considered as the variant of effective and safe therapy of children in post-eradication period

Postbiotic Modulation of Retinoic Acid Imprinted Mucosal-like Dendritic Cells by Probiotic Lactobacillus reuteri 17938 In Vitro.

Lactobacilli are widely used as probiotics with beneficial effects on infection-associated diarrhea, but also used in clinical trials of e.g., necrotizing enterocolitis and inflammatory bowel diseases. The possibility of using probiotic metabolic products, so-called postbiotics, is desirable as it could prevent possible side effects of live bacteria in individuals with a disturbed gut epithelial barrier. Here, we studied how Lactobacillus reuteri DSM 17938 cell-free supernatant (L. reuteri-CFS) influenced retinoic acid (RA)-driven mucosal-like dendritic cells (DC) and their subsequent effect on T regulatory cells (Treg) in vitro. RA clearly imprinted a mucosal-like DC phenotype with higher IL10 production, increased CD103 and CD1d expression, and a downregulated mRNA expression of several inflammatory-associated genes (NFκB1, RELB, and TNF). Treatment with L. reuteri-CFS further influenced the tolerogenic phenotype of RA-DC by downregulating most genes involved in antigen uptake, antigen presentation, and signal transduction as well as several chemokine receptors, while upregulating IL10 production. L. reuteri-CFS also augmented CCR7 expression on RA-DC. In cocultures, RA-DC increased IL10 and FOXP3 expression in Treg, but pre-treatment with L. reuteri-CFS did not further influence the Treg phenotype. In conclusion, L. reuteri-CFS modulates the phenotype and function of mucosal-like DC, implicating its potential application as postbiotic.

The Efficacy and Safety of the Probiotic Bacterium Lactobacillus reuteri DSM 17938 for Infantile Colic: A Meta-Analysis of Randomized Controlled Trials.

ObjectiveTo evaluate the efficacy and safety of Lactobacillus reuteri DSM 17938 for treating infantile colic.MethodsA systematic literature retrieval was carried out to obtain randomized controlled trials of L. reuteri DSM 17938 for infantile colic. Trials were performed before May 2015 and retrieved from the PubMed, EMBASE, Cochrane library, CNKI, WanFang, VIP, and CBM databases. Data extraction and quality evaluation of the trials were performed independently by two investigators. A meta-analysis was performed using STATA version 12.0.ResultsSix randomized controlled trials of 423 infants with colic were included. Of these subjects, 213 were in the L. reuteri group, and 210 were in the placebo group. Lactobacillus reuteri increased colic treatment effectiveness at two weeks (RR = 2.84; 95% CI: 1.24–6.50; p = 0.014) and three weeks (relative risk [RR] = 2.33; 95% CI: 1.38–3.93; P = 0.002) but not at four weeks (RR = 1.41; 95% CI: 0.52–3.82; P = 0.498). Lactobacillus reuteri decreased crying time (min/d) at two weeks (weighted mean difference [WMD] = –42.89; 95% CI: –60.50 to –25.29; P = 0.000) and three weeks (WMD = –45.83; 95% CI: –59.45 to –32.21; P = 0.000). In addition, L. reuteri did not influence infants’ weight, length or head circumference and was not associated with serious adverse events.Conclusions Lactobacillus reuteri possibly increased the effectiveness of treatment for infantile colic and decreased crying time at two to three weeks without causing adverse events. However, these protective roles are usurped by gradual physiological improvements. The study is limited by the heterogeneity of the trials and should be considered with caution. Higher quality, multicenter randomized controlled trials with larger samples are needed.

USE OF THE PROBIOTIC Lactobacillus reuteri DSM 17938 IN THE PREVENTION OF ANTIBIOTIC-ASSOCIATED INFECTIONS IN HOSPITALIZED BULGARIAN CHILDREN: A RANDOMIZED, CONTROLLED TRIAL

Objective: To evaluate the effectiveness of Lactobacillus reuteri DSM 17938 for the prevention of antibioticassociated diarrhoea and Clostridium difficile-related infections in hospitalized children in a Bulgarian hospital. Study design: Children (n=100, aged 3 to 12 years) admitted to the hospital for acute infections were enrolled in a randomized, double- blind, placebo-controlled trial. They were assigned to receive either a probiotic supplement containing 1 x 10 8 CFU Lactobacillus reuteri DSM 17938 in the form of one chewable tablet once per day (n=49) (BioGaia AB, Stockholm, Sweden) or placebo (n=48). The probiotic or placebo was taken 2 hours after lunch each day, during the entire period of antibiotic treatment at the hospital and for additional 7 days. Results: Data from 97 children were included in the final analysis. The incidence of diarrhoea (defined as at least 3 loose or watery stools per day in a 48-hour period that occurred during or up to 21 days after cessation of antibiotic treatment) was unexpectedly low in both groups - L. reuteri (n=1) versus placebo (n=1): 2,04 vs. 2,1 per 100 (p>0,05, risk ratio 1,02, 95% CI 0,7-1,4). L reuteri DSM 17938 did not significantly affect the incidence or severity of AAD diarrhoea and Clostridium difficile infection. We found unusually high colonisation rate of non-symptomatic C. difficile measured by toxin-specific ELISA. There was no difference between the probiotic and placebo groups for any of the other secondary outcomes (i.e., incidence of mild diarrhoea, frequency of stool samples positive for C. difficile toxin A and B at the beginning and at the end of study period, frequencies of other gastrointestinal symptoms in the same study period) (p<0,05). No adverse events were reported. Conclusion: Due to the low incidence of antibioticassociated diarrhoea in both groups, no conclusion can be made on the efficacy of L. reuteri DSM 17938 on AAD in hospitalized Bulgarian children. The probiotic did not affect the non-symptomatic high rate of C. difficile colonisation (33.3% in the placebo and 38.8% in the L. reuteri group at baseline) in this population. There was also no difference between groups regarding different gastrointestinal side effects.

The TRPV1 channel in rodents is a major target for antinociceptive effect of the probiotic Lactobacillus reuteri DSM 17938.

Certain probiotic bacteria have been shown to reduce distension-dependent gut pain, but the mechanisms involved remain obscure. Live luminal Lactobacillus reuteri (DSM 17938) and its conditioned medium dose dependently reduced jejunal spinal nerve firing evoked by distension or capsaicin, and 80% of this response was blocked by a specific TRPV1 channel antagonist or in TRPV1 knockout mice. The specificity of DSM action on TRPV1 was further confirmed by its inhibition of capsaicin-induced intracellular calcium increases in dorsal root ganglion neurons. Another lactobacillus with ability to reduce gut pain did not modify this response. Prior feeding of rats with DSM inhibited the bradycardia induced by painful gastric distension. These results offer a system for the screening of new and improved candidate bacteria that may be useful as novel therapeutic adjuncts in gut pain. Certain bacteria exert visceral antinociceptive activity, but the mechanisms involved are not determined. Lactobacillus reuteri DSM 17938 was examined since it may be antinociceptive in children. Since transient receptor potential vanilloid 1 (TRPV1) channel activity may mediate nociceptive signals, we hypothesized that TRPV1 current is inhibited by DSM. We tested this by examining the effect of DSM on the firing frequency of spinal nerve fibres in murine jejunal mesenteric nerve bundles following serosal application of capsaicin. We also measured the effects of DSM on capsaicin-evoked increase in intracellular Ca(2+) or ionic current in dorsal root ganglion (DRG) neurons. Furthermore, we tested the in vivo antinociceptive effects of oral DSM on gastric distension in rats. Live DSM reduced the response of capsaicin- and distension-evoked firing of spinal nerve action potentials (238 ± 27.5% vs. 129 ± 17%). DSM also reduced the capsaicin-evoked TRPV1 ionic current in DRG neuronal primary culture from 83 ± 11% to 41 ± 8% of the initial response to capsaicin only. Another lactobacillus (Lactobacillus rhamnosus JB-1) with known visceral anti-nociceptive activity did not have these effects. DSM also inhibited capsaicin-evoked Ca(2+) increase in DRG neurons; an increase in Ca(2+) fluorescence intensity ratio of 2.36 ± 0.31 evoked by capsaicin was reduced to 1.25 ± 0.04. DSM releasable products (conditioned medium) mimicked DSM inhibition of capsaicin-evoked excitability. The TRPV1 antagonist 6-iodonordihydrocapsaicin or the use of TRPV1 knock-out mice revealed that TRPV1 channels mediate about 80% of the inhibitory effect of DSM on mesenteric nerve response to high intensity gut distension. Finally, feeding with DSM inhibited perception in rats of painful gastric distension. Our results identify a specific target channel for a probiotic with potential therapeutic properties.