Twenty-five years of research on Saccharomyces boulardii trophic effects: updates and perspectives

The Potential Impact of Probiotics on Human Health: An Update on Their Health-Promoting Properties

Probiotics, known to be live microorganisms, have been shown to improve or restore the gut microbiota, which in turn has been linked to improved health. It is believed that probiotics are the modern equivalent of a panacea, with claims that they may treat or prevent different diseases both in children and adults (e.g., from colic in babies to cardiovascular disease, respiratory infection, and cancer in adults). Ever since the early 2000s, probiotic-based fermented foods have had a resurgence in popularity, mostly due to claims made regarding their health benefits. Fermented foods have been associated with the prevention of irritable bowel syndrome, lactose intolerance, gastroenteritis, and obesity, but also other conditions such as chronic diarrhea, allergies, dermatitis, and bacterial and viral infections, all of which are closely related to an unhealthy lifestyle. Recent and ongoing developments in microbiome/microbiota science have given us new research directions for probiotics. The new types, mechanisms, and applications studied so far, and those currently under study, have a great potential to change scientific understanding of probiotics' nutritional applications and human health care. The expansion of fields related to the study of the microbiome and the involvement of probiotics in its improvement foreshadow an era of significant changes. An expanding range of candidate probiotic species is emerging that can address newly elucidated data-driven microbial niches and host targets. In the probiotic field, new variants of microbiome-modulating interventions are being developed, including prebiotics, symbiotics, postbiotics, microbial consortia, live biotherapeutic products, and genetically modified organisms, with renewed interest in polyphenols, fibers, and fermented foods to ensure human health. This manuscript aims to analyze recent, emerging, and anticipated trends in probiotics (sources, doses, mechanism of action, diseases for which probiotics are administered, side effects, and risks) and create a vision for the development of related areas of influence in the field.

A Tunable and Expandable Transactivation System in Probiotic Yeast Saccharomyces boulardii

Precise transcriptional modulation is a key requirement for developing synthetic probiotics with predictably tunable functionalities. In this study, an expandable and tunable transactivation system was constructed and validated in probiotic yeast Saccharomyces boulardii. The use of nuclease-null Cas9 and scaffold RNA (scRNA) directed regulation enabled transactivation under the control of a synthetic promoter in S. boulardii. A synthetic promoter consisting of the scRNA target sequence and the core GAL7 promoter region restricted interference from the native galactose regulon. The system was readily expanded by introducing new target sequences to the promoter and scRNA. Complementarity between the promoter and scRNA, and binding specificity between scRNA and transcriptional activator, served as two layers of orthogonality of the transactivation. In addition, activator expression under the control of an inducible promoter enabled control of the transactivation via chemical inducer. The described system has the potential to enable engineering of probiotic yeast to more precisely perform therapeutic functions.

The Impacts of Dietary Fermented Mao-tai Lees on Growth Performance, Plasma Metabolites, and Intestinal Microbiota and Metabolites of Weaned Piglets

This study investigated the effects of dietary supplementation with fermented Mao-tai lees (FML) on growth performance, plasma metabolites, and intestinal microbiota and metabolites of weaned piglets. A total of 128 Duroc×Landrace×Yorkshire piglets (28-days old) were randomly assigned to one of four groups, feeding a basal diet (control group), a basal diet supplemented with 2, 4 or 6% FML, respectively, for 42days. The results showed that dietary 4% FML supplementation had higher (p<0.05) average daily gain (ADG) and plasma triglyceride concentration during days 1–14 of the trial than the other FML supplemented groups. In addition, dietary 2 and 4% FML supplementation increased (p<0.05) the ADG during days 15–28 of the trial and plasma total protein concentration on day 42 of the trial compared with the 6% FML supplement. The plasma concentrations of arginine, ethanolamine, histidine, isoleucine, lysine, methionine, proline, taurine, threonine, and tyrosine were increased (p<0.05) in the 4% FML group compared with the other three groups on day 14 of the trial. Dietary supplementation with 2–6% FML decreased (p<0.05) the plasma urea nitrogen concentration on day 14 of the trial and the abundance of Escherichia coli in the colon, and dietary 2 and 4% FML supplementation decreased (p<0.05) the abundance of sulfate-reducing bacteria compared with the control group. In the intestinal contents, a higher concentration of FML (6%) supplementation decreased (p<0.05) the colonic acetate concentration compared with the control and 2% FML groups, while 4% FML supplementation increased (p<0.05) the colonic cadaverine concentration compared with the other three groups. In conclusion, dietary 4% FML supplementation might contribute to the increased amino acids metabolism without affecting the growth performance of weaned piglets. Moreover, dietary 2 and 4% FML supplementation were also beneficial to intestinal health via decreasing the abundances of specific pathogens and increasing the concentrations of microbial metabolites in the gut, which provides the theoretical basis and data support for the application of FML in pigs.

Role of Recent Therapeutic Applications and the Infection Strategies of Shiga Toxin-Producing Escherichia coli

Shiga toxin-producing Escherichia coli (STEC) is a global foodborne bacterial pathogen that is often accountable for colon disorder or distress. STEC commonly induces severe diarrhea in hosts but can cause critical illnesses due to the Shiga toxin virulence factors. To date, there have been a significant number of STEC serotypes have been evolved. STECs vary from nausea and hemorrhoid (HC) to possible lethal hemolytic-based uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP). Inflammation-based STEC is usually a foodborne illness with Shiga toxins (Stx 1 and 2) thought to be pathogenesis. The STEC's pathogenicity depends significantly on developing one or more Shiga toxins, which can constrain host cell protein synthesis leading to cytotoxicity. In managing STEC infections, antimicrobial agents are generally avoided, as bacterial damage and discharge of accumulated toxins are thought the body. It has also been documented that certain antibiotics improve toxin production and the development of these species. Many different groups have attempted various therapies, including toxin-focused antibodies, toxin-based polymers, synbiotic agents, and secondary metabolites remedies. Besides, in recent years, antibiotics' efficacy in treating STEC infections has been reassessed with some encouraging methods. Nevertheless, the primary role of synbiotic effectiveness (probiotic and prebiotic) against pathogenic STEC and other enteropathogens is less recognized. Additional studies are required to understand the mechanisms of action of probiotic bacteria and yeast against STEC infection. Because of the consensus contraindication of antimicrobials for these bacterial pathogens, the examination was focused on alternative remedy strategies for STEC infections. The rise of novel STEC serotypes and approaches employed in its treatment are highlighted.

Probiotic Yeasts and Vibrio anguillarum Infection Modify the Microbiome of Zebrafish Larvae

The host microbiome plays an essential role in health and disease. Microbiome modification by pathogens or probiotics has been poorly explored especially in the case of probiotic yeasts. Next-generation sequencing currently provides the best tools for their characterization. Debaryomyces hansenii 97 (D. hansenii 97) and Yarrowia lipolytica 242 (Y. lipolytica 242) are yeasts that protect wildtype zebrafish (Danio rerio) larvae against a Vibrio anguillarum (V. anguillarum) infection, increasing their survival rate. We investigate the effect of these microorganisms on the microbiome and neutrophil response (inflammation) in zebrafish larvae line Tg(Bacmpx:GFP)ⁱ¹¹⁴. We postulated that preinoculation of larvae with yeasts would attenuate the intestinal neutrophil response and prevent modification of the larval microbiome induced by the pathogen. Microbiome study was performed by sequencing the V3-V4 region of the 16S rRNA gene and prediction of metabolic pathways by Piphillin in conventionally raised larvae. Survival and the neutrophil response were both evaluated in conventional and germ-free conditions. V. anguillarum infection resulted in higher neutrophil number in the intestinal area compared to non-infected larvae in both conditions. In germ-free conditions, infected larvae pre-inoculated with yeasts showed fewer neutrophil numbers than infected larvae. In both conditions, only D. hansenii 97 increased the survival of infected larvae. Beta diversity of the microbiota was modified by V. anguillarum and both yeasts, compared to non-inoculated larvae. At 3 days post-infection, V. anguillarum modified the relative abundance of 10 genera, and pre-inoculation with D. hansenii 97 and Y. lipolytica 242 prevented the modification of 5 and 6 of these genera, respectively. Both yeasts prevent the increase of Ensifer and Vogesella identified as negative predictors for larval survival (accounting for 40 and 27 of the variance, respectively). In addition, yeast pre-inoculation prevents changes in some metabolic pathways altered by V. anguillarum’s infection. These results suggest that both yeasts and V. anguillarum can shape the larval microbiota configuration in the early developmental stage of D. rerio. Moreover, modulation of key taxa or metabolic pathways of the larval microbiome by yeasts can be associated with the survival of infected larvae. This study contributes to the understanding of yeast–pathogen–microbiome interactions, although further studies are needed to elucidate the mechanisms involved.

In Vitro Probitotic Evaluation of Saccharomyces boulardii with Antimicrobial Spectrum in a Caenorhabditis elegans Model

In the present study, we screened for potential probiotic yeast that could survive under extreme frozen conditions. The antimicrobial and heat-stable properties of the isolated yeast strains Saccharomyces boulardii (S. boulardii) (KT000032, KT000033, KT000034, KT000035, KT000036, and KT000037) was analyzed and compared with commercial probiotic strains. The results revealed that the tested S. boulardii KT000032 strain showed higher resistance to gastric enzymes (bile salts, pepsin, and pancreatic enzyme) at low pH, with broad antibiotic resistance. In addition, the strain also showed efficient auto-aggregation and co-aggregation abilities and efficient hydrophobicity in the in-vitro and in-vivo C. elegens gut model. Further, the KT000032 strain showed higher antimicrobial efficiency against 13 different enteropathogens and exhibited commensal relationships with five commercial probiotic strains. Besides, the bioactive compounds produced in the cell-free supernatant of probiotic yeast showed thermo-tolerance (95 °C for two hours). Furthermore, the thermo-stable property of the strains will facilitate their incorporation into ready-to-eat food products under extreme food processing conditions.

Recent innovations in the production of selected specialty (non-traditional) beers

Customer demand for product diversity is the key driving force for innovations in the brewing industry. Specialty beers are regarded as a distinct group of beers different from two major types, lagers and ales, without established definitions or boundaries. Specialty beers, including low- to no-alcohol beer, low carbohydrate beer, gluten-free beer, sour beer, probiotic beer, and enriched beer, are exclusively brewed and developed keeping in mind their functionality, the health and wellbeing of the consumer, and emerging market trends. Compared with conventional beer-brewing, the production of specialty beers is technologically challenging and usually requires additional process steps, unique microorganisms, and special equipment, which in turn may incur additional costs. In addition, the maintenance of quality and stability of the products as well as consumer acceptability of the products are major challenges to successful commercialization. A harmonious integration of traditional brewing practices and modern technological approaches may hold potential for future developments. In the present review, latest developments in the fermentative production of selected specialty beers are discussed.

Antimicrobial mechanisms and applications of yeasts

Yeasts and humans have had a close relationship for millenia. Yeast have been used for food production since the first human societies. Since then, alternative uses have been discovered. Nowadays, antibiotic resistance constitutes a pressing need worldwide. In order to overcome this threat, one of the most important strategies is the search for new antimicrobials in natural sources. Moreover, biopreservation based on natural sources has emerged as an alternative to more common chemical preservatives. Yeasts constitute an underexploited source of antagonistic activity against other microorganisms. Here, we compile a summary of the antagonistic activity of yeast origin against other yeast and other microorganisms, such as bacteria or parasites. We present the mechanisms of action used by yeasts to display these activities. We also provide applications of these antagonistic activities in food industry and agriculture, medicine and veterinary, where yeast promise to play a pivotal role in the near future.

Potential Probiotic Yeasts Sourced from Natural Environmental and Spontaneous Processed Foods

In the last decades, there has been a growing interest from consumers in their food choices. Organic, natural, less processed, functional, and pre-probiotic products were preferred. Although, Saccharomyces cerevisiae var. boulardii is the most well-characterized probiotic yeast available on the market, improvement in probiotic function using other yeast species is an attractive future direction. In the present study, un-anthropized natural environments and spontaneous processed foods were exploited for wild yeast isolation with the goal of amplifying the knowledge of probiotic aptitudes of different yeast species. For this purpose, 179 yeast species were isolated, identified as belonging to twelve different genera, and characterized for the most important probiotic features. Findings showed interesting probiotic characteristics for some yeast strains belonging to Lachancea thermotolerans, Metschnikowia ziziphicola, Saccharomyces cerevisiae, and Torulaspora delbrueckii species, although these probiotic aptitudes were strictly strain-dependent. These yeast strains could be proposed for different probiotic applications, such as a valid alternative to, or in combination with, the probiotic yeast S. cerevisiae var. boulardii.

Recent Advancements in the Development of Modern Probiotics for Restoring Human Gut Microbiome Dysbiosis

A healthy gut is predominantly occupied by bacteria which play a vital role in nutrition and health. Any change in normal gut homeostasis imposes gut dysbiosis. So far, efforts have been made to mitigate the gastrointestinal symptoms using modern day probiotics. The majority of the probiotics strains used currently belong to the genera Lactobacillus, Clostridium, Bifidobacterium and Streptococcus. Recent advancements in culturomics by implementing newer techniques coupled with the use of gnotobiotic animal models provide a subtle ground to develop novel host specific probiotics therapies. In this review article, the recent advances in the development of microbe-based therapies which can now be implemented to treat a wide spectrum of diseases have been discussed. However, these probiotics are not classified as drugs and there is a lack of stringent law enforcement to protect the end users against the pseudo-probiotic products. While modern probiotics hold strong promise for the future, more rigorous regulations are needed to develop genuine probiotic products and characterize novel probiotics using the latest research and technology. This article also highlights the possibility of reducing antibiotic usage by utilizing probiotics developed using the latest concepts of syn and ecobiotics.

Comprehensive optimization of composite cryoprotectant for Saccharomyces boulardii during freeze-drying and evaluation of its storage stability

Saccharomyces boulardii (S. boulardii) is widely adopted in the diarrhea treatment for humans or livestock, so guaranteeing the survival rate of S. boulardii is the critical issue during freeze-drying process. In this study, the survival rate of S. boulardii with composite cryoprotectants during freeze-drying procedure and the subsequent storage were investigated. With the aid of response surface method, the composite cryoprotectants were comprehensively optimized to be lactose of 21.24%, trehalose of 22.00%, and sodium glutamate of 4.00%, contributing to the supreme survival rate of S. boulardii of 64.22 ± 1.35% with the viable cell number of 9.5 ± 0.07 × 10⁹ CFU/g, which was very close to the expected rate of 65.55% with a number of 9.6 × 10⁹ CFU/g. The accelerated storage test demonstrated that the inactivation rate constant of the freeze-dried S. boulardii powder was k_-18 = 8.04 × 10^-6. In addition, the freeze-dried goat milk powder results exhibited that the inactivation rate constants were k₄ = 4.48 × 10^-4 and k₂₅ = 9.72 × 10^-3 under 4 and 25 °C, respectively. This work provides a composite cryoprotectant formulation that has a good protective effect for the probiotic S. boulardii during freeze-drying process, possessing the potential application prospect in food, medicine, and even feed industry.

Saccharomyces boulardii CNCM I-745 Improves Intestinal Enzyme Function: A Trophic Effects Review

Several properties of the probiotic medicinal yeast Saccharomyces boulardii CNCM I-745 contribute to its efficacy to prevent or treat diarrhoea. Besides immunologic effects, pathogen-binding and anti-toxin effects, as well as positive effects on the microbiota, S boulardii CNCM I-745 also has pronounced effects on digestive enzymes of the brush border membrane, known as trophic effects. The latter are the focus of this review. Literature has been reviewed after searching Medline and PMC databases. All relevant non-clinical and clinical studies are summarized. S. boulardii CNCM I-745 synthesizes and secretes polyamines, which have a role in cell proliferation and differentiation. The administration of polyamines or S. boulardii CNCM I-745 enhances the expression of intestinal digestive enzymes as well as nutrient uptake transporters. The signalling mechanisms leading to enzyme activation are not fully understood. However, polyamines have direct nucleic acid–binding capacity with regulatory impact. S. boulardii CNCM I-745 induces signalling via the mitogen-activated protein kinase pathway. In addition, effects on the phosphatidylinositol-3 kinase (PI3K) pathway have been reported. As an additional direct effect, S. boulardii CNCM I-745 secretes certain enzymes, which enhance nutrient acquisition for the yeast and the host. The increased availability of digestive enzymes seems to be one of the mechanisms by which S. boulardii CNCM I-745 counteracts diarrhoea; however, also people with certain enzyme deficiencies may profit from its administration. More studies are needed to fully understand the mechanisms of trophic activation by the probiotic yeast.

Evaluation of antimicrobial activity and probiotic properties of wild-strain Pichia kudriavzevii isolated from frozen idli batter

The present research was undertaken to study the probiotic characteristics of Pichia kudriavzevii isolated from frozen idli batter. Polymerase chain reaction amplification with 18S rRNA primers confirmed Pichia kudriavzevii, a xylose-utilizing probiotic strain. It was resistant to physiological concentrations of bile salts, pepsin and pancreatic enzyme. It also showed efficient auto-aggregation as well as co-aggregation ability with four commercial probiotic yeasts and exhibited good hydrophobicity in xylene and toluene. The strain inhibited the growth of 13 enteropathogens and showed a commensal relationship with four commercial probiotic yeast and bacteria. Moreover, it was resistant to 30 antibiotics with different modes of action. The yeast exhibited thermotolerance up to 95 °C for 2 h. The cell-free supernatants were also found to be heat stable, indicating the presence of thermostable secondary metabolites. Hence it could be exploited as starter culture, co-culture or probiotic in the preparation of fermented products or incorporated in heatable foods as well. Copyright © 2016 John Wiley & Sons, Ltd.

Probiotics for vaginal health in South Africa: what is on retailers' shelves?

BACKGROUND

Probiotics are widely used to improve gastrointestinal (GI) health, but they may also be useful to prevent or treat gynaecological disorders, including bacterial vaginosis (BV) and candidiasis. BV prevalence is high in South Africa and is associated with increased HIV risk and pregnancy complications. We aimed to assess the availability of probiotics for vaginal health in retail stores (pharmacies, supermarkets and health stores) in two major cities in South Africa.

METHODS

A two-stage cluster sampling strategy was used in the Durban and Cape Town metropoles. Instructions for use, microbial composition, dose, storage and manufacturers' details were recorded.

RESULTS

A total of 104 unique probiotics were identified in Cape Town and Durban (66.4% manufactured locally). Cape Town had more products than Durban (94 versus 59 probiotics), although 47% were common between cities (49/104). Only four products were explicitly for vaginal health. The remainder were for GI health in adults (51.0%) or infants (17.3%). The predominant species seen overall included Lactobacillus acidophilus (53.5%), L. rhamnosus (37.6%), Bifidobacterium longum ssp. longum (35.6%) and B. animalis ssp. lactis (33.7%). Products for vaginal health contained only common GI probiotic species, with a combination of L. acidophilus/B. longum ssp. longum/B. bifidum, L. rhamnosus/L. reuteri or L. rhamnosus alone, despite L. crispatus, L. gasseri, and L. jensenii being the most common commensals found in the lower female reproductive tract.

CONCLUSION

This survey highlights the paucity of vaginal probiotics available in South Africa, where vaginal dysbiosis is common. Most vaginal products contained organisms other than female genital tract commensals.

Influence of Saccharomyces boulardii CNCM I-745on the gut-associated immune system

Background

The probiotic Saccharomyces boulardii CNCM I-745 (also known as Saccharomyces cerevisiae HANSEN CBS 5926; in the following S. boulardii) has proven its effectiveness in preventive and therapeutic treatment of many gastrointestinal diseases, especially diseases associated with acute diarrhea. In particular, antibiotic-associated diarrhea, Clostridium difficile-associated diarrhea, traveller’s diarrhea, as well as acute diarrhea due to common viral and bacterial infections in children and adults.

Aim

The aim of this review is to summarize the experimental studies elucidating the molecular and immunological mechanisms by which these clinically proven effects are archived, with an emphasis on the gut-associated immune system. The main focus is laid on anti-inflammatory and immune-modulatory action of S. boulardii involved in bacterial or enterotoxin-mediated diarrhea and inflammation. An attempt is made to differentiate between the effects associated with cellular versus soluble factors and between prophylactic and therapeutic effects.

Methods

A literature search was performed in PubMed/PubMed Central for the effects of S. boulardii on the gut-associated immune system (focus acute diarrhea).

Results and conclusion

S. boulardii exhibits its positive effect by the direct effects on pathogens or their toxins as well as by influencing the host’s infection-induced signaling cascades and its innate and adaptive immune system. The combination of these mechanisms results in a reduction of the pathogens’ ability for adhesion or colonization and an attenuation of the overreacting inflammatory immune response. Thereby, the integrity of the intestinal epithelial cell layer is preserved or restored, and the diarrheic leakage of fluids into the intestinal lumen is attenuated.

Effect of topically applied Saccharomyces boulardii on the healing of acute porcine wounds: a preliminary study

BACKGROUND

Normal wound healing progresses through a series of interdependent physiological events: inflammation, angiogenesis, re-epithelialization, granulation tissue formation and extracellular matrix remodeling. Alterations in this process as well as the bacterial type and load on a wound may alter the wound healing rate. The purpose of this study was to evaluate the effect of topical Saccharomyces boulardii on the healing of acute cutaneous wounds, using a prospective, controlled, experimental study, with six purpose bred landrace pigs.

RESULTS

All wounds healed without apparent complications. Comparison of the mean 3D and 2D wound surface area measurements showed no significant difference between treatment groups as wounds decreased similarly in size over the duration of the study. A significant reduction in wound surface area was identified sooner using 3D assessments (by day 9) compared to 2D assessments (by day 12) (P < 0.001). There was no significant effect of treatment group on the number of multiple isolates or the most common isolates obtained relative to control wounds. There was no histologically appreciable difference between the wounds of the different groups.

CONCLUSIONS

Topical application of Saccharomyces boulardii does not hasten wound healing or change the wounds' microbiome under the conditions reported in this study.

Saccharomyces boulardii CNCM I-745 reduces the duration of diarrhoea, length of emergency care and hospital stay in children with acute diarrhoea

Evidence from the literature has shown that Saccharomyces boulardii provides a clinically significant benefit in the treatment of acute infectious diarrhoea in children. In this multicentre, randomised, prospective, controlled, single blind clinical trial performed in children with acute watery diarrhoea, we aimed to evaluate the impact of S. boulardii CNCM I-745 in hospitalised children, in children requiring emergency care unit (ECU) stay and in outpatient settings. The primary endpoint was the duration of diarrhoea (in hours). Secondary outcome measures were duration of hospitalisation and diarrhoea at the 3(rd) day of intervention. In the whole study group (363 children), the duration of diarrhoea was approximately 24 h shorter in the S. boulardii group (75.4±33.1 vs 99.8±32.5 h, P<0.001). The effect of S. boulardii (diarrhoea-free children) was observed starting at 48 h. After 72 h, only 27.3% of the children receiving probiotic still had watery diarrhoea, in contrast to 48.5% in the control group (P<0.001). The duration of diarrhoea was significantly reduced in the probiotic group in hospital, ECU and outpatient settings (P<0.001, P<0.01 and P<0.001, respectively). The percentage of diarrhoea-free children was significantly larger after 48 and 72 h in all settings. The mean length of hospital stay was shorter with more than 36 h difference in the S. boulardii group (4.60±1.72 vs 6.12±1.71 days, P<0.001). The mean length of ECU stay was shorter with more than 19 h difference in the probiotic group (1.20±0.4 vs 2.0±0.3 days, P<0.001). No adverse effects related to the probiotic were noted. Because treatment can shorten the duration of diarrhoea and reduce the length of ECU and hospital stay, there is likely a social and economic benefit of S. boulardii CNCM I-745 in adjunction to oral rehydration solution in acute infectious gastroenteritis in children.

Baker's yeast (Saccharomyces cerevisiae) antigen in obese and normal weight subjects

Baker's yeast (Saccharomyces cerevisiae) and its cell wall components have been used as one of the alternatives to antibiotic growth promoters in the feed industry. Antibodies to cell wall mannan of this yeast (ASCA) have been traditionally used in the study of Crohn's disease (CD). We applied ASCA in relation to obesity. This study aims (i) to determine the concentration of ASCA (immunoglobulin A [IgA] and immunoglobulin G [IgG]) in obese compared with normal weight individuals and (ii) to determine if there is a correlation between ASCA concentrations, obesity indices and C-reactive protein. Forty obese individuals (body mass index [BMI] > 35 kg m(-2) ) and 18 healthy (BMI < 25 kg m(-2) ) volunteers participated in this case-control study. Binding activity of serum IgA and IgG to the cell wall mannan of S. cerevisiae was measured by enzyme-linked immunosorbent assay. More than one-third of the obese individual (35%) showed elevated titres of ASCA compared with the control group (5%). This antibody was positively associated with weight (P = 0.01), BMI (P = 0.02) and waist circumference (P = 0.02), but not with C-reactive protein. It seems that ASCA are not only specific for CD but are also associated with obesity. S. cerevisiae or a related antigen may play a role in the matrix of this complex condition.

Saccharomyces boulardii prevention of the hepatic injury induced by Salmonella Enteritidis infection

Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis) is the predominant cause of serovar-associated food-borne outbreaks in many countries and causes significant clinical symptoms of liver injury, enteritis, and diarrheal diseases. Saccharomyces boulardii is used in clinical application for prophylaxis and the treatment of a variety of diseases caused by bacterial infection. We used a mouse model of Salmonella Enteritidis infection, which included pretreatment with S. boulardii, to reveal the protection mechanisms of S. boulardii against Salmonella Enteritidis infection, including the translocation of Salmonella Enteritidis to the liver 10 days after Salmonella Enteritidis challenge, and the colonisation of Salmonella Enteritidis and the formation of hepatic tissue lesions in mice after Salmonella Enteritidis challenge on the 10th day. Compared with Salmonella Enteritidis infection in mice, S. boulardii decreased Salmonella Enteritidis translocation to the liver by 96%, and 99% of Salmonella Enteritidis colonised the cecum on the 10th day. Saccharomyces boulardii also abated hepatic tissue injury caused by the infiltration of neutrophilic granulocytes, lymphocytes, and plasmocytes by decreasing the translocation of Salmonella to the liver. These findings demonstrated that S. boulardii is an effective agent in the prevention of the hepatic injury induced by Salmonella Enteritidis infection in a mouse model.

Saccharomyces boulardii CNCM I-745 in different clinical conditions

INTRODUCTION

Saccharomyces boulardii is a well-known probiotic worldwide, and there are numerous studies including experimental and clinical trials in children and adults by the use of S. boulardii.

AREAS COVERED

The objective of the present report is to provide an update on the evidence for the efficacy of S. boulardii CNCM I-745 in different clinical conditions. Saccharomyces boulardii is one of the best-studied probiotics in acute gastroenteritis (AGE) and is shown to be safe and to reduce the duration of diarrhea and hospitalization by about 1 day. Saccharomyces boulardii is one of the recommended probiotics for AGE in children by European Society of Paediatric Infectious Diseases and European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN). Saccharomyces boulardii is also a recommended probiotic for the prevention of antibiotic-associated diarrhea (AAD), and a recent study showed promising results for the treatment of AAD in children. There is insufficient evidence to recommend the long-term use of S. boulardii in patients with irritable bowel syndrome. Although some clinical studies showed positive effects of S. boulardii on inflammation, there is no clinical evidence that S. boulardii is useful in inflammatory bowel disease. Saccharomyces boulardii could be used in patients needing Helicobacter pylori eradication because the S. boulardii improves compliance, decreases the side effects and moderately increases the eradication rate. There are new promising results (improving feeding tolerance, shorten the course of hyperbilirubinemia), but we do still not recommend the routine use of S. boulardii in newborns.

EXPERT OPINION

Saccharomyces boulardii CNCM I-745 is a good example for the statement that each probiotic needs to be taxonomically characterized and its efficacy and safety should be documented individually in different clinical settings.

Prevention and treatment of diarrhoea with Saccharomyces boulardii in children with acute lower respiratory tract infections

The aim of this study was to determine whether Saccharomyces boulardii prevents and treats diarrhoea and antibiotic-associated diarrhoea (AAD) in children. A total of 333 hospitalised children with acute lower respiratory tract infection were enrolled in a 2-phase open randomised controlled trial. During the 1st phase, all children received intravenous antibiotics (AB). They were randomly allocated to group A (S. boulardii 500 mg/day + AB, n=167) or group B (AB alone, n=166) and followed for 2 weeks. Diarrhoea was defined as ≥3 loose/watery stools/day during at least 2 days, occurring during treatment and/or up to 2 weeks after AB therapy had stopped. AAD was considered when diarrhoea was caused by Clostridium difficile or when stool cultures remained negative. In the 2nd phase of the study, group B patients who developed diarrhoea were randomly allocated to two sub-groups: group B1 (S. boulardii + oral rehydration solution (ORS)) and group B2 (ORS alone). Data from 283 patients were available for analysis. Diarrhoea prevalence was lower in group A than in group B (11/139 (7.9%) vs. 42/144 (29.2%); relative risk (RR): 0.27, 95% confidence interval (CI): 0.1-0.5). S. boulardii reduced the risk of AAD (6/139 (4.3%) vs. 28/144 (19.4%); RR: 0.22; 95% CI: 0.1-0.5). When group B patients developed diarrhoea (n=42), S. boulardii treatment during 5 days (group B1) resulted in lower stool frequency (P<0.05) and higher recovery rate (91.3% in group B1 vs. 21.1% in B2; P<0.001). The mean duration of diarrhoea in group B1 was shorter (2.31±0.95 vs. 8.97±1.07 days; P<0.001). No adverse effects related to S. boulardii were observed. S. boulardii appeared to be effective in the prevention and treatment of diarrhoea and AAD in children treated with intravenous antibiotics.

Protective effect of bifidobacteria in an experimental model ofClostridium difficileassociated colitis

The aim of this study was to evaluate the ability ofBifidobacteriumstrains to prevent the effects associated withClostridium difficileinfection in a hamster model of enterocolitis. After clindamycin treatment (30 mg/kg), animals were infected intragastrically withC. difficile(5×108CFU per animal). Seven days prior to antibiotic administration, probiotic treatment was started by administering bacterial suspensions of bifidobacteria in drinking water. Strains CIDCA 531, CIDCA 5310, CIDCA 5316, CIDCA 5320, CIDCA 5323 and CIDCA 5325 were used. Treatment was continued during all the experimental period. Development of diarrhoea, enterocolitis and mortality were evaluated. All the infected animals belonging to the placebo group developed enterocolitis (5/5) and only two dead (2/5) whereas in the group administered withBifidobacterium bifidumstrain CIDCA 5310 the ratio of animals with enterocolitis or dead decreased significantly (1/5 and 0/5 respectively). Biological activity of caecum contents was evaluated in vitro on Vero cells. Animals treated with strain CIDCA 5310 presented lower biological activity than those belonging to the placebo group. The present study shows the potential of selected strains of bifidobacteria to antagonise, in vivo, the virulence ofC. difficile.

Antimicrobial and probiotic properties of yeasts: from fundamental to novel applications

The yeasts constitute a large and heterogeneous group of microorganisms that are currently attracting increased attention from scientists and industry. Numerous and diverse biological activities make them promising candidates for a wide range of applications not limited to the food sector. In addition to their major contribution to flavor development in fermented foods, their antagonistic activities toward undesirable bacteria, and fungi are now widely known. These activities are associated with their competitiveness for nutrients, acidification of their growth medium, their tolerance of high concentrations of ethanol, and release of antimicrobial compounds such as antifungal killer toxins or "mycocins" and antibacterial compounds. While the design of foods containing probiotics (microorganisms that confer health benefits) has focused primarily on Lactobacillus and Bifidobacterium, the yeast Saccharomyces cerevisiae var. boulardii has long been known effective for treating gastroenteritis. In this review, the antimicrobial activities of yeasts are examined. Mechanisms underlying this antagonistic activity as well as recent applications of these biologically active yeasts in both the medical and veterinary sectors are described.

Saccharomyces boulardii improves intestinal epithelial cell restitution by inhibiting αvβ5 integrin activation state

Intestinal epithelial cell damage is frequently seen in the mucosal lesions of infectious or inflammatory bowel diseases such as ulcerative colitis or Crohn's disease. Complete remission of these diseases requires both the disappearance of inflammation and the repair of damaged epithelium. Saccharomyces boulardii (Sb, Biocodex) is a non-pathogenic yeast widely used as a preventive and therapeutic probiotic for the prevention and treatment of diarrhea and other gastrointestinal disorders. We recently showed that it enhances the repair of intestinal epithelium through activation of α2β1 integrin collagen receptors. In the present study, we demonstrated that α2β1 integrin is not the sole cell-extracellular matrix receptor involved during Sb-mediated intestinal restitution. Indeed, by using cell adhesion assays, we showed that Sb supernatant contains heat sensitive molecule(s), with a molecular weight higher than 9 kDa, which decreased αvβ5 integrin-mediated adhesion to vitronectin by competing with the integrin. Moreover, Sb-mediated changes in cell adhesion to vitronectin resulted in a reduction of the αvβ5signaling pathway. We used a monolayer wounding assay that mimics in vivo cell restitution to demonstrate that down-modulation of the αvβ5 integrin-vitronectin interaction is related to Sb-induced cell migration. We therefore postulated that Sb supernatant contains motogenic factors that enhance cell restitution through multiple pathways, including the dynamic fine regulation of αvβ5 integrin binding activity. This could be of major importance in diseases characterized by severe mucosal injury, such as inflammatory and infectious bowel diseases.

Efficacy and safety of the probiotic Saccharomyces boulardii for the prevention and therapy of gastrointestinal disorders

Several clinical trials and experimental studies strongly suggest a place for Saccharomyces boulardii as a biotherapeutic agent for the prevention and treatment of several gastrointestinal diseases. S. boulardii mediates responses resembling the protective effects of the normal healthy gut flora. The multiple mechanisms of action of S. boulardii and its properties may explain its efficacy and beneficial effects in acute and chronic gastrointestinal diseases that have been confirmed by clinical trials. Caution should be taken in patients with risk factors for adverse events. This review discusses the evidence for efficacy and safety of S. boulardii as a probiotic for the prevention and therapy of gastrointestinal disorders in humans.

Effectiveness and safety of Saccharomyces boulardii for acute infectious diarrhea

INTRODUCTION

Acute diarrhea continues to be a leading cause of morbidity, hospitalization and mortality worldwide and probiotics have been proposed as a complementary therapy in the treatment of acute diarrhea. Regarding the treatment of acute diarrhea, a few probiotics including Saccharomyces boulardii seem to be promising therapeutic agents.

AREAS COVERED

We performed a systematic review and meta-analysis regarding the use of S. boulardii in the treatment of acute infectious diarrhea with relevant studies that searched with the PubMed, Embase, Scopus, Google Scholar, the Cochrane Controlled Trials Library, and the Cochrane Database of Systematic Reviews through October 2011. This review describes the effects of S. boulardii on the duration of diarrhea, the risk of diarrhea during the treatment (especially at the third day) and duration of hospitalization in patients with acute infectious diarrhea. This review also focused on the potential effects of S. boulardii for acute infectious diarrhea due to different etiological causes.

EXPERT OPINION

S. boulardii significantly reduced the duration of diarrhea approximately 24 h and that of hospitalization approximately 20 h. S. boulardii shortened the initial phase of watery stools; mean number of stools started to decrease at day 2; moreover, a significant reduction was reported at days 3 and 4. This systematic review and meta-analysis of the efficacy of S. boulardii in the treatment of acute infectious diarrhea show that there is strong evidence that this probiotic has a clinically significant benefit, whatever the cause, including in developing countries. Therefore, with S. boulardii, the shortened duration of diarrhea and the reduction in hospital stay result in social and economic benefits.

Clostridium difficile infection: an update on epidemiology, risk factors, and therapeutic options

PURPOSE OF REVIEW

The incidence and severity of Clostridium difficile infection (CDI) around the world has increased over the past 20 years due to the emergence of hypervirulent strains, increased use and misuse of antibiotics, and the increase of susceptible at-risk populations. Treatments currently available for CDI are inadequate to impede the increasing spread and virulence of the infection, avoid recurrence in chronic patients or prevent infection in at-risk populations.

RECENT FINDINGS

New and promising evidence has been presented during the past year, focusing on two major points: preservation of gut microflora and optimization of immune response to CDI and toxins.

SUMMARY

The review aims to summarize the most recent evidence available on the epidemiology, risk factors and treatment of CDI. New antibiotics with selected action on C. difficile and limited effect on microflora (fidaxomicin) and donor fecal transplantation seem to have a relevant efficacy in treating CDI and reducing its recurrence. The use of selected monoclonal antibodies directed against C. difficile toxins in addition to standard therapy is a new, promising approach for the treatment of recurrent cases. Vaccination could be an additional weapon against CDI. New robust data are needed before recommendations can be made to abandon current treatment based on vancomycin and metronidazole and move toward new frontiers.

Saccharomyces boulardii improves intestinal cell restitution through activation of the α2β1 integrin collagen receptor

Intestinal epithelial cell damage is frequently seen in the mucosal lesions of inflammatory bowel diseases such as ulcerative colitis or Crohn's disease. Complete remission of these diseases requires both the cessation of inflammation and the migration of enterocytes to repair the damaged epithelium. Lyophilized Saccharomyces boulardii (Sb, Biocodex) is a nonpathogenic yeast widely used as a therapeutic agent for the treatment and prevention of diarrhea and other gastrointestinal disorders. In this study, we determined whether Sb could accelerate enterocyte migration. Cell migration was determined in Sb force-fed C57BL6J mice and in an in vitro wound model. The impact on α2β1 integrin activity was assessed using adhesion assays and the analysis of α2β1 mediated signaling pathways both in vitro and in vivo. We demonstrated that Sb secretes compounds that enhance the migration of enterocytes independently of cell proliferation. This enhanced migration was associated with the ability of Sb to favor cell-extracellular matrix interaction. Indeed, the yeast activates α2β1 integrin collagen receptors. This leads to an increase in tyrosine phosphorylation of cytoplasmic molecules, including focal adhesion kinase and paxillin, involved in the integrin signaling pathway. These changes are associated with the reorganization of focal adhesion structures. In conclusion Sb secretes motogenic factors that enhance cell restitution through the dynamic regulation of α2β1 integrin activity. This could be of major importance in the development of novel therapies targeting diseases characterized by severe mucosal injury, such as inflammatory and infectious bowel diseases.

Interaction of Saccharomyces boulardii with intestinal brush border membranes: key to probiotic effects?

The probiotic Saccharomyces boulardii exerts beneficial effects in humans, which include trophic effects, anti-inflammatory effects, antisecretory effects, inhibition of toxins, immunostimulatory effects, and resistance to bacterial overgrowth. This short communication discusses the interactions of the probiotic with brush border membrane (BBM) constituents because most of these effects are BBM mediated. The use of bacterial and yeast probiotics has increased dramatically in more and more clinical states, but their exact mechanisms of action remain largely unknown. The present communication focuses on the interactions of a confirmed yeast probiotic (S boulardii) on the constituents of BBMs.

Systematic review and meta-analysis of Saccharomyces boulardii in adult patients

This article reviews the evidence for efficacy and safety of Saccharomyces boulardii (S. boulardii) for various disease indications in adults based on the peer-reviewed, randomized clinical trials and pre-clinical studies from the published medical literature (Medline, Clinical Trial websites and meeting abstracts) between 1976 and 2009. For meta-analysis, only randomized, blinded controlled trials unrestricted by language were included. Pre-clinical studies, volunteer studies and uncontrolled studies were excluded from the review of efficacy and meta-analysis, but included in the systematic review. Of 31 randomized, placebo-controlled treatment arms in 27 trials (encompassing 5029 study patients), S. boulardii was found to be significantly efficacious and safe in 84% of those treatment arms. A meta-analysis found a significant therapeutic efficacy for S. boulardii in the prevention of antibiotic-associated diarrhea (AAD) (RR = 0.47, 95% CI: 0.35-0.63, P < 0.001). In adults, S. boulardii can be strongly recommended for the prevention of AAD and the traveler's diarrhea. Randomized trials also support the use of this yeast probiotic for prevention of enteral nutrition-related diarrhea and reduction of Helicobacter pylori treatment-related symptoms. S. boulardii shows promise for the prevention of C. difficile disease recurrences; treatment of irritable bowel syndrome, acute adult diarrhea, Crohn's disease, giardiasis, human immunodeficiency virus-related diarrhea; but more supporting evidence is recommended for these indications. The use of S. boulardii as a therapeutic probiotic is evidence-based for both efficacy and safety for several types of diarrhea.

Probiotic yeasts: Anti-inflammatory potential of various non-pathogenic strains in experimental colitis in mice

AIM: To evaluate the in vitro immunomodulation capacity of various non-pathogenic yeast strains and to investigate the ability of some of these food grade yeasts to prevent experimental colitis in mice.

METHODS: In vitro immunomodulation was assessed by measuring cytokines [interleukin (IL)-12p70, IL-10, tumor necrosis factor and interferon γ] released by human peripheral blood mononuclear cells after 24 h stimulation with 6 live yeast strains (Saccharomyces ssp.) and with bacterial reference strains. A murine model of acute 2-4-6-trinitrobenzene sulfonic acid (TNBS)-colitis was next used to evaluate the distinct prophylactic protective capacities of three yeast strains compared with the performance of prednisolone treatment.

RESULTS: The six yeast strains all showed similar non-discriminating anti-inflammatory potential when tested on immunocompetent cells in vitro. However, although they exhibited similar colonization patterns in vivo, some yeast strains showed significant anti-inflammatory activities in the TNBS-induced colitis model, whereas others had weaker or no preventive effect at all, as evidenced by colitis markers (body-weight loss, macroscopic and histological scores, myeloperoxidase activities and blood inflammatory markers).

CONCLUSION: A careful selection of strains is required among the biodiversity of yeasts for specific clinical studies, including applications in inflammatory bowel disease and other therapeutic uses.

The effect of Saccharomyces boulardii on reducing irinotecan-induced intestinal mucositis and diarrhea

To investigate the efficiency of Saccharomyces boulardii on irinotecan-induced mucosal damage and diarrhea in rats, fifty rats were randomized into three groups with 20 rats in two study groups and 10 rats in the control group. Control group did not receive any treatment. Irinotecan (60 mg/kg) alone was administered intravenously once a day for four consecutive days to the rats of Group A. Throughout the experiment, Group B rats were additionally given Saccharomyces boulardii (800 mg/kg) for 3 days before administration of irinotecan and 7 days throughout the experiment. Delayed diarrhea was more severe in Group A than Group B (P = 0.009). The weight loss was 34.7 +/- 3.8 mg for Group A, while it was 17.4 +/- 1.7 mg for Group B (P < 0.001). Findings of mucositis most clearly appeared in the jejunum. Regarding edema (P = 0.003), leukocyte migration (P = 0.038), and inflammation (P = 0.006) significant recovery was detected in the mucosa of rats receiving Saccharomyces boulardii. Villous thickness was significantly greater in Group A than Group B (P < 0.001). The results indicate that Saccharomyces boulardii provided significant improvement in irinotecan-induced diarrhea and mucositis.