Prevention of clindamycin-induced mortality in hamsters by Saccharomyces boulardii

The role of gut fungi in Clostridioides difficile infection

Clostridioides difficile, the etiological agent of C. difficile infection (CDI), elicits a spectrum of diarrheal symptoms with varying severity and the potential to result in severe complications such as colonic perforation, pseudomembranous colitis, and toxic megacolon. The perturbation of gut microbiome, often triggered by antibiotic usage, represents the primary factor augmenting the risk of CDI. This underscores the significance of interactions between C. difficile and the microbiome in determining pathogen adaptability. In recent years, researchers have increasingly recognized the pivotal role played by intestinal microbiota in host health and its therapeutic potential as a target for medical interventions. While extensive evidence has been established regarding the involvement of gut bacteria in CDI, our understanding of symbiotic interactions between hosts and fungi within intestinal microbiota remains limited. Herein, we aim to comprehensively elucidate both composition and key characteristics of gut fungal communities that significantly contribute to CDI, thereby enhancing our comprehension from pharmacological and biomarker perspectives while exploring their prospective therapeutic applications for CDI.

Clostridioides (Clostridium) Difficile in Food-Producing Animals, Horses and Household Pets: A Comprehensive Review

Clostridioides (Clostridium) difficile is ubiquitous in the environment and is also considered as a bacterium of great importance in diarrhea-associated disease for humans and different animal species. Food animals and household pets are frequently found positive for toxigenic C. difficile without exposing clinical signs of infection. Humans and animals share common C. difficile ribotypes (RTs) suggesting potential zoonotic transmission. However, the role of animals for the development of human infection due to C. difficile remains unclear. One major public health issue is the existence of asymptomatic animals that carry and shed the bacterium to the environment, and infect individuals or populations, directly or through the food chain. C. difficile ribotype 078 is frequently isolated from food animals and household pets as well as from their environment. Nevertheless, direct evidence for the transmission of this particular ribotype from animals to humans has never been established. This review will summarize the current available data on epidemiology, clinical presentations, risk factors and laboratory diagnosis of C. difficile infection in food animals and household pets, outline potential prevention and control strategies, and also describe the current evidence towards a zoonotic potential of C. difficile infection.

Diversity of Saccharomyces boulardii CNCM I-745 mechanisms of action against intestinal infections

The yeast Saccharomyces boulardii CNCM I-745 is one of the probiotics recommended for the prevention of antibiotic-associated diarrhea. Studies conducted in vivo and in vitro demonstrated that in the case of infectious diseases there are two potential sites of action of Saccharomyces boulardii CNCM I-745: (1) An action on enteropathogenic microorganisms (adhesion of bacteria and their elimination or an effect on their virulence factors: Toxins, lipopolysaccharide, etc.); and (2) a direct action on the intestinal mucosa (trophic effects, effects on epithelial reconstitution, anti-secretory effects, anti-inflammatory, immunomodulators). Oral administration of Saccharomyces boulardii CNCM I-745 to healthy subjects does not alter their microbiota. However, in the case of diseases associated with the use of antibiotics or chronic diarrhea, Saccharomyces boulardii CNCM I-745 can restore the intestinal microbiota faster. The interaction of Saccharomyces boulardii CNCM I-745 with the innate immune system have been recently demonstrated thus opening up a new therapeutic potential of this yeast in the case of diseases associated with intestinal infections but also other pathologies associated with dysbiosis such as inflammatory diseases.

Beneficial effects of Saccharomyces boulardii CNCM I-745 on clinical disorders associated with intestinal barrier disruption

Intestinal barrier defects lead to "leaky gut syndrome", defined as an increase in intestinal permeability that allows the passage of luminal content into intestinal tissue and the bloodstream. Such a compromised intestinal barrier is the main factor underlying the pathogenesis of inflammatory bowel disease, but also commonly occurs in various systemic diseases such as viral infections and metabolic syndrome. The non-pathogenic yeast Saccharomyces boulardii CNCM I-745 has demonstrated its effectiveness as a probiotic in the prevention and treatment of antibiotic-associated, infectious and functional diarrhea. Via multiple mechanisms of action implicated in intestinal barrier function, S. boulardii has beneficial effects on altered intestinal microbiota and epithelial barrier defects in different pathologies. The well-studied probiotic yeast S. boulardii plays a crucial role in the preservation and/or restoration of intestinal barrier function in multiple disorders. This could be of major interest in diseases characterized by alterations in intestinal barrier function.

Probiotic Saccharomyces boulardii CNCM I-745 prevents outbreak-associated Clostridium difficile-associated cecal inflammation in hamsters

C. difficile infection (CDI) is a common debilitating nosocomial infection associated with high mortality. Several CDI outbreaks have been attributed to ribotypes 027, 017, and 078. Clinical and experimental evidence indicates that the nonpathogenic yeast Saccharomyces boulardii CNCM I-745 (S.b) is effective for the prevention of CDI. However, there is no current evidence suggesting this probiotic can protect from CDI caused by outbreak-associated strains. We used established hamster models infected with outbreak-associated C. difficile strains to determine whether oral administration of live or heat-inactivated S.b can prevent cecal tissue damage and inflammation. Hamsters infected with C. difficile strain VPI10463 (ribotype 087) and outbreak-associated strains ribotype 017, 027, and 078 developed severe cecal inflammation with mucosal damage, neutrophil infiltration, edema, increased NF-κB phosphorylation, and increased proinflammatory cytokine TNFα protein expression. Oral gavage of live, but not heated, S.b starting 5 days before C. difficile infection significantly reduced cecal tissue damage, NF-κB phosphorylation, and TNFα protein expression caused by infection with all strains. Moreover, S.b-conditioned medium reduced cell rounding caused by filtered supernatants from all C. difficile strains. S.b-conditioned medium also inhibited toxin A- and B-mediated actin cytoskeleton disruption. S.b is effective in preventing C. difficile infection by outbreak-associated via inhibition of the cytotoxic effects of C. difficile toxins.

Bacillus amyloliquefaciens as prophylactic treatment for Clostridium difficile-associated disease in a mouse model

BACKGROUND AND AIM

Probiotics might offer an attractive alternative for standard antibiotic therapy to treat Clostridium difficile infections (CDI). We specifically selected a Bacillus amyloliquefaciens strain for its high in vitro antibacterial activity against C. difficile and tested its efficacy to prevent CDI in a mouse model.

METHODS

B. amyloliquefaciens supernatant was tested against a large collection of C. difficile strains using an agar well diffusion test. B. amyloliquefaciens was orally administered to C57BL/6 mice in which CDI was induced using C. difficile VPI 10463, and its effect was compared with control mice receiving no treatment and mice receiving Saccharomyces boulardii. Mice were followed up daily for signs of disease including weight loss. At necropsy, the colon was collected and subjected to histopathological analysis. C. difficile toxin A/B levels and colon weight/length and colon/body weight ratios were calculated.

RESULTS

B. amyloliquefaciens supernatant was able to inhibit the growth of all C. difficile strains. Results of the in vivo trial indicated a significant weight loss for untreated and S. boulardii-treated mice as compared to B. amyloliquefaciens-treated mice. C. difficile toxin A and B levels were significantly higher for untreated and S. boulardii-treated mice than B. amyloliquefaciens-treated mice. A significantly lower degree of colon damage was detected for B. amyloliquefaciens-treated mice as compared to untreated and S. boulardii-treated mice, based on histopathological analysis, colon weight/length and colon/body weight ratios.

CONCLUSION

Administration of B. amyloliquefaciens was successful in preventing CDI in a mouse model.

Clinical update for the diagnosis and treatment of Clostridium difficile infection

Clostridium difficile infection (CDI) presents a rapidly evolving challenge in the battle against hospital-acquired infections. Recent advances in CDI diagnosis and management include rapid changes in diagnostic approach with the introduction of newer tests, such as detection of glutamate dehydrogenase in stool and polymerase chain reaction to detect the gene for toxin production, which will soon revolutionize the diagnostic approach to CDI. New medications and multiple medical society guidelines have introduced changing concepts in the definitions of severity of CDI and the choice of therapeutic agents, while rapid expansion of data on the efficacy of fecal microbiota transplantation heralds a revolutionary change in the management of patients suffering multiple relapses of CDI. Through a comprehensive review of current medical literature, this article aims to offer an intensive review of the current state of CDI diagnosis, discuss the strengths and limitations of available laboratory tests, compare both current and future treatments options and offer recommendations for best practice strategies.

Probiotics for the treatment of Clostridium difficile associated disease

The purpose of this review paper is to update the current and potential future role of probiotics for Clostridium difficile-associated disease (CDAD). Included in this review, is an update on the testing of newer probiotics (e.g., Bacillus coagulans GBI-30, 6086) in animal models of CDAD. There is a focus on the modulation of signal transduction pathways (i.e., transcription factors like cAMP response element-binding, activator protein 1, and nuclear factor kappa B), as well as the inhibition of certain kinases (e.g., p38 mitogen activated protein kinases) by probiotics. Inhibition of signal transduction by probiotics, such as Saccharomyces boulardii, result in multiple effects on intestinal fluid secretion, neutrophil influx into the colon, inflammation, and colonocyte apoptosis that may positively impact CDAD. Recent clinical approaches with probiotics, for the prevention of primary and recurrent CDAD, are also summarized in this review paper. Future directions for the treatment of CDAD by probiotics are also mentioned in this review. In particular, the use of multi-strain probiotic formulations such as Ecologic^® AAD and VSL #3^® may represent a rationale pharmacological approach, particularly as adjunctive therapies for CDAD. Understanding the mechanistic basis of CDAD, and how probiotics interfere at ceratin steps in the pathogenic process, may also present the opportunity to design other multi-strain probiotics that could have a future impact on CDAD.

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.

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.

Models for the study of Clostridium difficile infection

Models of Clostridium difficile infection (C. difficile) have been used extensively for Clostridium difficile (C. difficile) research. The hamster model of C. difficile infection has been most extensively employed for the study of C. difficile and this has been used in many different areas of research, including the induction of C. difficile, the testing of new treatments, population dynamics and characterization of virulence. Investigations using in vitro models for C. difficile introduced the concept of colonization resistance, evaluated the role of antibiotics in C. difficile development, explored population dynamics and have been useful in the evaluation of C. difficile treatments. Experiments using models have major advantages over clinical studies and have been indispensible in furthering C. difficile research. It is important for future study programs to carefully consider the approach to use and therefore be better placed to inform the design and interpretation of clinical studies.

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.

Treatment of Clostridium difficile-associated disease

Clostridium difficile infection is an increasing burden to the health care system, totaling more than $1 billion/year in the United States. Treatment of patients with C difficile infection with metronidazole or vancomycin reduces morbidity and mortality, although the number of patients that do not respond to metronidazole is increasing. Despite initial response rates of greater than 90%, 15%-30% of patients have a relapse in symptoms after successful initial therapy, usually in the first few weeks after treatment is discontinued. Failure to develop specific antibody response has recently been identified as a critical factor in recurrence. The review discusses the different management strategies for initial and recurrent symptomatic C difficile infections.

Treatment of recurrent Clostridium difficile-associated disease

Recurrent Clostridium difficile-associated disease (RCDAD) is a difficult treatment problem--once a patient has one recurrence of the disease the likelihood of further recurrences is markedly increased. Repeat antibiotics are usually indicated, either metronidazole or vancomycin. Tapering and pulsing the antibiotic dose after a 10-day standard course decreases the incidence of recurrences compared with abruptly stopping antibiotics after a simple 10-day course. If recurrences continue after two courses of metronidazole, vancomycin may be preferable to avoid the risk of neurotoxicity that is associated with prolonged metronidazole use. There is also a role for probiotics in the treatment of RCDAD; Saccharomyces boulardii has been shown to decrease recurrences by about 50%, especially when combined with high-dose vancomycin. Other microbiologic approaches include the restoration of normal colonic flora by fecal enema or by nasogastric tube, but these have not been studied in controlled trials. In addition, there are numerous new treatment approaches that are under development, including a vaccine, which promise to aid the future treatment of RCDAD as well as prevention of initial CDAD.

Saccharomyces boulardii inhibits water and electrolytes changes induced by castor oil in the rat colon

The biotherapeutic agent Saccharomyces boulardii has been shown to inhibit castor oil-induced diarrhoea in rats. The present study investigated the mechanism(s) of this antidiarrhoeal effect in terms of water and electrolyte (sodium, potassium and chloride) changes using two rat models. A single oral dose of S. boulardii of up to 12 x 10(10) CFU/kg of viable cells did not inhibit castor oil-induced fluid secretion in the enteropooling model. However, the yeast dose dependently reduced castor oil induced fluid secretion into the colon, with a significant protection at 12 x 10(10) CFU/kg. In this model, castor oil reversed net sodium and chloride absorption into net secretion, and increased net potassium secretion into the lumen. Single pre-treatment with S. boulardii at 4 and 12 x 10(10) CFU/kg dose dependently decreased these electrolyte changes. In conclusion, S. boulardii possesses potent anti-secretory properties versus water and electrolyte secretion induced by castor oil in the rat colon.

Inducible nitric oxide synthase involvement in the mechanism of action of Saccharomyces boulardii in castor oil-induced diarrhoea in rats

The biotherapeutic agent Saccharomyces boulardii has been shown to inhibit castor oil-induced diarrhoea in rats in a dose-response fashion, and one of the suggested mechanisms of action included involvement of the nitric oxide pathway. The present study was designed to address this mechanism of action by firstly measuring the effects of S. boulardii on the inducible nitric oxide synthase (iNOS) isoform activity in vitro. Second, the effects of S. boulardii on the increase in colonic citrulline level associated with castor oil treatment were examined. In vitro, S. boulardii showed a dose-dependent inhibition of iNOS activity with an IC50 of 0.89 mg/ml. In the rat diarrhoea model, the antidiarrhoeal effect of S. boulardii was confirmed using a single oral dose of 12 x 10(10) CFU/kg (viable cells). In this model, castor oil significantly elevated citrulline level from 2526+/-164 to 3501+/-193 nmol/g in the colon. When the rats were treated with the same antidiarrhoeal single dose of S. boulardii, no increase in citrulline level was observed. Moreover, the iNOS inhibitor 1400 W at 10 mg/kg and the inhibitor of iNOS expression dexamethasone at 1 mg/kg, administered subcutaneously, blocked the citrulline production induced by the laxative. Taken together, these findings confirm the involvement of inhibition of the inducible isoform of nitric oxide synthase in the mechanism of action of S. boulardii in diarrhoea.

Veterinary pharmacovigilance. Part 3. Adverse effects of veterinary medicinal products in animals and on the environment

Like humans, animals may experience adverse effects when treated with medicinal products. These effects may be related to the pharmacological or toxicological properties of the substances used or they may arise because of hypersensitivity. Veterinary medicinal products may also possess the ability to harm the environment. This paper reviews the potential of veterinary medicinal products to cause adverse effects in animals and on the environment.

Studies on the time course of the effects of the probiotic yeast Saccharomyces boulardii on electrolyte transport in pig jejunum

Orally administered Saccharomyces boulardii (synonym Saccharomyces cerevisiae Hansen CBS 5926) has already been shown to affect relevant functions of the mucosa in pig jejunum such as lowering the secretory response to theophylline or stimulating sodium/glucose cotransport, but knowledge of time-dependent relationship is minimal. In this study we examined the effects of S. boulardii on sodium (Na+) and chloride (Cl-) transport in pig jejunum under nonstimulated (basal) and stimulated (secretory) conditions. For this purpose the conventional Ussing chamber method was used for measuring electrical parameters (short circuit currents, Isc; tissue conductances, G(T)) and electrolyte transport of isolated intact jejunal epithelia in the absence and presence of the secretagogue theophylline (10 mM, serosal side). Time profiles of the mucosa response were assessed by treating animals perorally with S. boulardii for 0 (control), 3, 8, and 16 days. Intestinal tissues were obtained from growing pigs in the weight range between 25 and 40 kg. All animals were fed twice daily and received 1.0-1.6 kg/day of a standard diet avoiding probiotics as food additives. After a 9- to 10-day adaptation period the diets for treated animals were supplemented with approximately 1.8 x 10(7) colony forming units (CFU)/g feed of the probiotic. Whereas basal tissue conductances were not affected by treatment duration, basal Isc values decreased significantly during 8 days of treatment, by 26%, indicating a lower electrogenic net ion transport, which, however, was reconstituted after 16 days. This effect could be explained by almost the same reduction of basal Jms of Na+ during 8 days of treatment, whereas respective flux rates in the opposite direction remained stable. Under basal conditions unidirectional and net flux rates of Cl- were not affected by S. boulardii. Induction of secretory conditions by theophylline revealed pronounced increases in net Cl- secretion but this effect was more than 60% lower after 8-day S. boulardii application, and this was reflected by a respectively lower Isc stimulation. Interestingly, this inhibitory effect on the secretory response could no longer be observed in the 16-day group. And this was reflected by a respectively lower Isc stimulation. A similar effect could be observed regarding net Na+ flux rates. Residual fluxes were affected neither by S. boulardii nor by theophylline, therefore, Isc values can be explained completely by respective Na+ and Cl- fluxes. In conclusion, S. boulardii has specific duration-dependent effects on the secretory response of the pig jejunal mucosa which developed during 8-day treatment but disappeared during further application. Thus, this study supports the concept that probiotics may exert beneficial effects in the gastrointestinal tract.

Probiotics, antibiotic-associated diarrhoea and Clostridium difficile diarrhoea in humans

Probiotics are living organisms which, when ingested, have a beneficial therapeutic effect. Examples are bacteria, especially Lactobacillus rhamnosus GG, and the yeast Saccharomyces boulardii. Controlled trials indicate a benefit of both of these in the prevention of antibiotic-associated diarrhoea. Other less effective probiotics are Lactinex, Enterococcus faecium and bifidobacteria. In the difficult clinical problem of recurrent Clostridium difficile disease, S. boulardii as an adjunct to antibiotics has shown benefit in controlled trials. There is, however, less convincing evidence for the efficacy of Lactobacillus GG in this disease. Additional controlled trials and safety studies are needed before there can be a widespread endorsement of probiotics for these two conditions.

Dose-response relationship and mechanism of action of Saccharomyces boulardii in castor oil-induced diarrhea in rats

For biotherapeutic agents, there is a lack of information on dose-response relationships and mechanism of action. The present study was designed to address these issues for Saccharomyces boulardii using the rat model of castor oil-induced diarrhea. A single dose of Saccharomyces boulardii at 12 x 10(10) CFU/kg of viable cells given 1 hr before castor oil administration significantly reduced the onset of diarrhea. Repeated ingestion of the yeast, twice daily between 1.2 and 12 x 10(10) CFU/kg for 5 days before castor oil, showed a dose-response relationship. The percentage of rats with diarrhea decreased and a stronger protection was afforded by the repeated treatment. The mechanism of action of Saccharomyces boulardii in this model was investigated with two classes of antagonists, naloxone and L-arginine. The effect of Saccharomyces boulardii was not inhibited by naloxone but was significantly reduced by L-arginine. This last result suggests a novel mechanism of action for Saccharomyces boulardii involving a possible inhibition of nitric oxide production by the yeast.

Biotherapeutics and biotherapy of surgical enteropathies

Probiotic agents are living micro-organisms that, upon ingestion, exert health benefits beyond inherent general nutrition. In this context, we must differentiate between biotherapeutics as approved drugs and dietary supplements and food products containing prebiotic bacteria that are not considered drugs. At present, the only biotherapeutic agent which is prescribable in some European countries, indicated to relieve specific diseases, is the yeast Saccharomyces boulardii. In this review, we consider the various pre-clinical and clinical aspects of biotherapeutics as basic drugs and the biotherapeutic powers of their use in the treatment of some surgical enteropathies.

Experimental effects of Saccharomyces boulardii on diarrheal pathogens

Saccharomyces boulardii is a selected strain of yeast that may have applications in the prevention and treatment of intestinal infections. The animal models and in vitro studies developed to elucidate the mechanisms of this protection are reviewed and discussed.

Preclinical and clinical pharmacology of biotherapeutic agents: Saccharomyces boulardii

Probiotic agents are living microorganisms that, upon ingestion, exert health benefits beyond inherent general nutrition. In this context, we must differentiate between biotherapeutics as approved drugs and dietary supplements and food products containing probiotic bacteria that are not considered drugs. At present the only biotherapeutic agent which is prescribable in some European countries, indicated to relieve specific diseases, is the yeast Saccharomyces boulardii. In this review we consider the various preclinical and clinical aspects of biotherapeutics as basic drugs and the biotherapeutic powers of their use in the treatment of some surgical enteropathies.

Infectious causes of chronic diarrhea

Chronic diarrhea can be seen in association with specific pathogens, usually parasites and occasionally some bacteria. This article reviews pathogens causing chronic diarrhea in immunocompetent individuals and provides a rational diagnostic approach.

Saccharomyces boulardii does not stimulate mucosal hyperplasia after intestinal resection in the rat

BACKGROUND

Polyamines have been shown to be important regulators of the intestinal adaptation process after massive bowel resection. Saccharomyces boulardii is yeast that has the ability to synthesize polyamines. Therefore. S. boulardii may be useful in the treatment of short bowel syndrome.

METHODS

Twenty 150-g male Sprague-Dawley rats were subjected to 80% jejunoileal resection. Another 20 animals received transection and closure and served as pair fed controls. One half of the resected rats and one half of the controls were given S. boulardii 25 mg/day.

RESULTS

After 2 weeks, mucosal mass (mg/cm bowel) did not differ between treated and non-treated animals despite the presence of a marked resection effect. Mucosal DNA, protein, and sucrase activity likewise did not differ. Subsequently, the experiment was repeated four times the original dose (100 mg/day) and found comparable results. In the proximal bowel, mucosal mass was 92+/-6 mg/cm in treated animals versus 107+/-8 mg/cm in untreated rats. In the distal small bowel, comparable values were 85+/-5 mg/cm and 88+/-4 mg/cm. Again, mucosal DNA, protein, and sucrase activity levels paralleled these results.

CONCLUSIONS

Although S. boulardii may stimulate polyamine synthesis, it does not seem to be helpful in augmenting gut adaptation in this animal model of short bowel syndrome.

Saccharomyces boulardii stimulates intestinal immunoglobulin A immune response to Clostridium difficile toxin A in mice

Saccharomyces boulardii is a nonpathogenic yeast that protects against antibiotic-associated diarrhea and recurrent Clostridium difficile colitis. The administration of C. difficile toxoid A by gavage to S. boulardii-fed BALB/c mice caused a 1.8-fold increase in total small intestinal immunoglobulin A levels (P = 0.003) and a 4.4-fold increase in specific intestinal anti-toxin A levels (P < 0.001). Enhancing host intestinal immune responses may be an important mechanism for S. boulardii-mediated protection against diarrheal illnesses.

Non-antibiotic therapy for Clostridium difficile infection

Treatment of Clostridium difficile infection with metronidazole or vancomycin is successful in the majority of cases, but relapse occurs in 15% to 20% of patients, and in some the infection can remain chronic for months or years. The use of non-antibiotic therapies for this infection is theoretically attractive, as they would enable the normal colonic microflora to be reconstituted which is a requirement for permanent eradication of this pathogen. Over the past decade a number of non-antibiotic approaches to eliminate or neutralize C. difficile or its toxins have been proposed, including probiotic therapy with non-pathogenic microorganisms and several forms of immunotherapy. These alternative approaches are in their infancy, but initial reports appear to support efficacy against this stubborn infection.

Effect of Saccharomyces boulardii on cAMP- and Ca2+ -dependent Cl- secretion in T84 cells

Several reports have confirmed that the cooperative interaction between cAMP- and Ca2+-mediated transduction pathways may contribute to the stimulatory or inhibitory regulation of Cl- secretion in intestinal epithelium. Saccharomyces boulardii has been shown to inhibit cholera toxin-induced secretion in rat jejunum. We have identified a 120-kDa protein in medium conditioned by Saccharomyces boulardii that reduces cholera toxin-induced cAMP in intestinal cells. The present study evaluated the effect of medium conditioned by Saccharomyces boulardii on cAMP- and Ca2+-mediated Cl- secretion in T84 cells. Experiments performed with cAMP agonists revealed that 1 hr of preincubation of cells with medium conditioned by Saccharomyces boulardii was necessary to elicit a 40-50% reduction in receptor (cholera toxin, prostaglandin E2, and vasoactive intestinal polypeptide) and nonreceptor (forskolin) mediated cAMP synthesis and 125I efflux. Secretion induced by carbachol was inhibited when cells were pretreated for 1 hr with medium conditioned by Saccharomyces boulardii despite the absence of inhibition of Ins (1,4,5)P3. From this study we conclude that Saccharomyces boulardii exerts an inhibitory effect in vitro on Cl- secretion mediated through both cAMP- and Ca2+-mediated signaling pathways.

Saccharomyces boulardii protease inhibits the effects of Clostridium difficile toxins A and B in human colonic mucosa

Saccharomyces boulardii is a nonpathogenic yeast used in the treatment of Clostridium difficile diarrhea and colitis. We have reported that S. boulardii inhibits C. difficile toxin A enteritis in rats by releasing a 54-kDa protease which digests the toxin A molecule and its brush border membrane (BBM) receptor (I. Castagliuolo, J. T. LaMont, S. T. Nikulasson, and C. Pothoulakis, Infect. Immun. 64:5225-5232, 1996). The aim of this study was to further evaluate the role of S. boulardii protease in preventing C. difficile toxin A enteritis in rat ileum and determine whether it protects human colonic mucosa from C. difficile toxins. A polyclonal rabbit antiserum raised against purified S. boulardii serine protease inhibited by 73% the proteolytic activity present in S. boulardii conditioned medium in vitro. The anti-protease immunoglobulin G (IgG) prevented the action of S. boulardii on toxin A-induced intestinal secretion and mucosal permeability to [3H]mannitol in rat ileal loops, while control rabbit IgG had no effect. The anti-protease IgG also prevented the effects of S. boulardii protease on digestion of toxins A and B and on binding of [3H]toxin A and [3H]toxin B to purified human colonic BBM. Purified S. boulardii protease reversed toxin A- and toxin B-induced inhibition of protein synthesis in human colonic (HT-29) cells. Furthermore, toxin A- and B-induced drops in transepithelial resistance in human colonic mucosa mounted in Ussing chambers were reversed by 60 and 68%, respectively, by preexposing the toxins to S. boulardii protease. We conclude that the protective effects of S. boulardii on C. difficile-induced inflammatory diarrhea in humans are due, at least in part, to proteolytic digestion of toxin A and B molecules by a secreted protease.

Saccharomyces boulardii protease inhibits Clostridium difficile toxin A effects in the rat ileum

Saccharomyces boulardii, a nonpathogenic yeast, is effective in treating some patients with Clostridium difficile diarrhea and colitis. We have previously reported that S. boulardii inhibits rat ileal secretion in response to C. difficile toxin A possibly by releasing a protease that digests the intestinal receptor for this toxin (C. Pothoulakis, C. P. Kelly, M. A. Joshi, N. Gao, C. J. O'Keane, I. Castagliuolo, and J. T. LaMont, Gastroenterology 104: 1108-1115, 1993). The aim of this study was to purify and characterize this protease. S. boulardii protease was partially purified by gel filtration on Sephadex G-50 and octyl-Sepharose. The effect of S. boulardii protease on rat ileal secretion, epithelial permeability, and morphology in response to toxin A was examined in rat ileal loops in vivo. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified S. boulardii protease revealed a major band at 54 kDa. Pretreatment of rat ileal brush border (BB) membranes with partially purified protease reduced specific toxin A receptor binding (by 26%). Partially purified protease digested the toxin A molecule and significantly reduced its binding to BB membranes in vitro (by 42%). Preincubation of toxin A with S. boulardii protease inhibited ileal secretion (46% inhibition, P < 0.01), mannitol permeability (74% inhibition, P < 0.01), and histologic damage caused by toxin A. Thus, S. boulardii protease inhibits the intestinal effects of C. difficile toxin A by proteolysis of the toxin and inhibition of toxin A binding to its BB receptor. Our results may be relevant to the mechanism by which S. boulardii exerts its protective effects in C. difficile infection in humans.

Saccharomyces boulardii protease inhibits Clostridium difficile toxin A effects in the rat ileum

Saccharomyces boulardii, a nonpathogenic yeast, is effective in treating some patients with Clostridium difficile diarrhea and colitis. We have previously reported that S. boulardii inhibits rat ileal secretion in response to C. difficile toxin A possibly by releasing a protease that digests the intestinal receptor for this toxin (C. Pothoulakis, C. P. Kelly, M. A. Joshi, N. Gao, C. J. O'Keane, I. Castagliuolo, and J. T. LaMont, Gastroenterology 104: 1108-1115, 1993). The aim of this study was to purify and characterize this protease. S. boulardii protease was partially purified by gel filtration on Sephadex G-50 and octyl-Sepharose. The effect of S. boulardii protease on rat ileal secretion, epithelial permeability, and morphology in response to toxin A was examined in rat ileal loops in vivo. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified S. boulardii protease revealed a major band at 54 kDa. Pretreatment of rat ileal brush border (BB) membranes with partially purified protease reduced specific toxin A receptor binding (by 26%). Partially purified protease digested the toxin A molecule and significantly reduced its binding to BB membranes in vitro (by 42%). Preincubation of toxin A with S. boulardii protease inhibited ileal secretion (46% inhibition, P < 0.01), mannitol permeability (74% inhibition, P < 0.01), and histologic damage caused by toxin A. Thus, S. boulardii protease inhibits the intestinal effects of C. difficile toxin A by proteolysis of the toxin and inhibition of toxin A binding to its BB receptor. Our results may be relevant to the mechanism by which S. boulardii exerts its protective effects in C. difficile infection in humans.

Uptake of yeast (Saccharomyces boulardii) in normal and rotavirus treated intestine

BACKGROUND

There has recently been a growing interest in the use of the non-pathogenic yeast Saccharomyces boulardii, in the treatment of gastrointestinal disorders, including diarrhoea. The full effects of administration of the yeast are not fully understood.

AIMS

To investigate the morphological effects of inoculated S boulardii on mouse intestinal villi, both in control animals and those treated with rotavirus.

METHODS

Seven day old BALB/c seronegative mice were intubated with either rotavirus (30 microliters orally) or S boulardii (1.5 g/kg) or both rotavirus and S boulardii administered together. Control animals were given saline only. Animals were killed by decapitation 48 hours post-treatment. The middle region of the small intestine was studied using light microscopy and transmission and scanning electron microscopy, including backscattered electron imaging.

RESULTS

Animals treated with rotavirus with or without S boulardii developed severe diarrhoea and showed morphological villous changes such as stromal separation and increased epithelial vacuolation. Specimens treated with S boulardii contained yeast particles within the mucosal tissues.

CONCLUSION

The administration of S boulardii did not influence the changes produced by rotavirus, but yeast particles appeared to be taken up by the villous mucosa, with the predominant route apparently being uptake between adjacent epithelial cells.

The effects of supplementing diets with Saccharomyces cerevisiae var. boulardii on male poult performance and ileal morphology

This study determined the effects of three levels of supplemental yeast of Saccharomyces cerevisiae var. boulardii (SCB) on commercial male poult performance and ileum morphology. One hundred and sixty Nicholas poults were randomly assigned to 16 battery cages (10 poults per cage, 4 cages per diet) from 1 to 21 d of age (DOA). Poults were fed diets (26% CP) consisting of corn-soybean (CS, control), CS + .01% SCB, CS + .02% SCB, and CS + .06% SCB. At 21 DOA, 30 poults fed the CS and CS + .02% SCB diets (from 1 to 21 DOA) were randomly selected within each diet, placed in 1 of 6 cages (5 poults per cage, 3 cages per diet), and fed their respective diet to 35 DOA. Body weights and feed consumptions (FC) were measured at 21 and 35 DOA and morphological comparisons of ileal tissues were conducted at 35 DOA. Increased BW (P < .004) at 7, 14, and 21 DOA were observed for poults fed diets containing SCB at .01, .02, and .06% of the diet. No dietary differences (P > .05) were observed in FC or feed:gain ratios from 1 to 21 DOA. Increased (P < .03) BW were maintained from 21 to 35 DOA for poults fed .02% SCB, whereas no dietary differences (P > .05) in FC or feed:gain were observed. Histological examination of ileal sections from poults (35 DOA) fed the CS and CS + .02% SCB diets revealed a decrease (P < .04) in the number of goblet cells per millimeter of villus height and a decreased (P < .02) crypt depth in poults receiving .02% SCB. No dietary differences (P > .05) were observed for either villus height or width.

Saccharomyces boulardii inhibits secretagogue-mediated adenosine 3',5'-cyclic monophosphate induction in intestinal cells

BACKGROUND/AIMS

The yeast Saccharomyces boulardii inhibits the secretion induced by cholera toxin (CT) in rat jejunum. The present study was aimed at unraveling the mechanism by which S. boulardii protects intestinal cells against CT.

METHODS

CT-induced adenosine 3',5'-cyclic monophosphate (cAMP) levels were measured by radioimmunoassay in intestinal epithelial cells IEC-6 or HT29-D4 cells exposed to whole yeast or to culture medium conditioned by S. boulardii (Sb-conditioned medium).

RESULTS

Sb-conditioned medium significantly reduced CT-induced cAMP levels in IEC-6 cells. This effect was eliminated by heat treatment, trypsin hydrolysis, and trichloroacetic acid precipitation of Sb-conditioned medium. When conditioned medium was fractionated on polyacrylamide gel under nondenaturing conditions, neutralizing activity was shown to be associated with a 120-kilodalton protein. The neutralizing activity was not attributable to proteolytic activity against CT. Sb-conditioned medium reduced the amount of cAMP induced by CT as well as Escherichia coli thermolabile toxin or forskolin in HT29-D4 cells. The modulation of secretagogue-induced cAMP by Sb-conditioned medium did not occur in the presence of pertussis toxin.

CONCLUSIONS

These results suggest that the neutralization of CT by S. boulardii is mediated by a specific yeast protein and involves a receptor that is negatively coupled to adenylate cyclase.

Recovery and elimination of the biotherapeutic agent, Saccharomyces boulardii, in healthy human volunteers

Saccharomyces boulardii (Sb) is a nonpathogenic yeast used to treat intestinal illnesses such as pseudomembranous colitis and antibiotic associated diarrhea. The behavior of this biotherapeutic agent in humans was determined (1) in investigating the effect of dose on the steady-state level and recovery and (2) in quantitating the effect of ampicillin on the recovery and elimination profile. As the Sb dose increased, the mean steady-state concentration of Sb increased significantly. The percentage recovery was dose independent. When a single Sb dose was administered 24 hr after beginning a course of ampicillin, there was a significant increase (P < 0.01) in both the area under the concentration versus time curve and the maximum fecal concentration compared to values obtained without ampicillin. Ampicillin increased steady-state recovery of the drug about twofold (P < 0.05) and steady-state levels about 2.4 times (P < 0.01). These studies have shown that there is a relationship between the dose and the amount of Sb recovered and that perturbation of the GI flora by ampicillin increases steady-state levels of Sb.

Saccharomyces boulardii inhibits Clostridium difficile toxin A binding and enterotoxicity in rat ileum

BACKGROUND

Saccharomyces boulardii is a nonpathogenic yeast used for the prevention and treatment of Clostridium difficile-associated diarrhea and colitis. However, the mechanism by which S. boulardii exerts its protective effects remains unclear.

METHODS

The binding of [3H]toxin A to its brush border receptor preincubated with S. boulardii-cultured suspension or filtered conditioned medium was measured in vitro. The effect of toxin A on secretion, epithelial permeability, and morphology in rat ileal loops in vivo was also examined in rats pretreated with S. boulardii.

RESULTS

S. boulardii reduced [3H]toxin A-receptor binding in a dose-dependent fashion. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of ileal brush border exposed to S. boulardii-conditioned medium revealed a diminution of all brush border proteins. Treatment of rats with S. boulardii suspension reduced fluid secretion and mannitol permeability caused by toxin A.

CONCLUSIONS

S. boulardii may reduce some of the enterotoxic effects of toxin A by inhibiting toxin A-receptor binding. This effect appears to be manifested by a secreted product of the yeast, possibly a protease.

Effect of oral Saccharomyces boulardii treatment on the activity of Clostridium difficile toxins in mouse digestive tract

Human antibiotic-associated diarrhoea and pseudomembranous colitis are partly due to toxin production by Clostridium difficile. It is now well documented that Saccharomyces boulardii protects against C. difficile induced diseases. In an attempt to understand better the mechanism of this protective effect, the action of S. boulardii on a crude toxin preparation was studied in vitro and in vivo. The results showed that the yeast had no effect on the toxins in vitro but was able to protect mice inoculated with these toxins. Furthermore, the observation by scanning electron microscopy that the mucosa of S. boulardii protected mice was not damaged suggest that the yeast mainly acts on the intestinal mucosa.

Effect of yogurt on clindamycin-induced Clostridium difficile colitis in hamsters

Yogurt exhibits in vitro bactericidal activity against a variety of pathogenic microorganisms, including Clostridium difficile. In the present studies, we tested whether yogurt ingestion could prevent or ameliorate antibiotic associated colitis in the clindamycin-treated hamster model. Male golden Syrian hamsters were given 5 mg/kg clindamycin subcutaneously 24 hr before and 6 hr following inoculation with 0.5 ml of less than 10, 10(3), 10(5), or 10(6) CFU/ml of C. difficile. Hamsters in the control group ingested chow and water ad libitum, whereas the experimental group ingested chow and a 1:1 (v/v) mixture of yogurt and water ad libitum, beginning 24 hr before the first injection of clindamycin and continuing throughout the course of the study. Animals were monitored for colonization with C. difficile, pathological evidence of colitis, and death. Mortality was 100% in yogurt-treated animals, and all animals showed histological changes of severe colitis. Fecal and intestinal segment cultures were positive for C. difficile in all animals. Thus, in the hamster model, we found no evidence to support the possible efficacy of yogurt in the prevention of C. difficile colitis.

Kinetics of Saccharomyces cerevisiae elimination from the intestines of human volunteers and effect of this yeast on resistance to microbial colonization in gnotobiotic mice

When healthy volunteers were given a daily dose of 3 x 10(8) life-dehydrated Saccharomyces cerevisiae cells for 5 days, the volunteers excreted 10(5) living yeast cells per g of feces at first, but the yeast cells disappeared within 5 days of the end of treatment. In gnotobiotic mice, S. cerevisiae administered alone colonized the intestinal tract but did not interfere with previous or subsequent colonization by a variety of potentially enteropathogenic microorganisms. When these microorganisms were present, the intestinal counts of S. cerevisiae were greatly reduced.

Passive immunization of hamsters against disease caused by Clostridium difficile by use of bovine immunoglobulin G concentrate

Gestating Holstein cows were vaccinated with Clostridium difficile toxoid prepared from the culture filtrate of a strain that produces high levels of toxins A and B and other antigens. A bovine immunoglobulin G (IgG) concentrate was prepared from colostrum collected at parturition. The results of our studies showed that hamsters treated prophylactically with the hyperimmune bovine IgG concentrate were protected against C. difficile disease. These results suggest that orally administered hyperimmune bovine IgG specific for C. difficile culture filtrate may be useful in prophylaxis against C. difficile disease.

Influence of antibiotics on the recovery and kinetics of Saccharomyces boulardii in rats

Saccharomyces boulardii (SB) is a yeast that is used for the prevention and treatment of antibiotic-associated diarrhea and for the treatment of pseudomembranous colitis. Since SB will most commonly be used when the bacterial flora of the gastrointestinal tract have been disrupted by antibiotic treatment, the influence of different antibiotics on the kinetics and recovery of SB in feces was investigated in rats. Following a single oral dose, SB concentrations in feces were measured for periods of 1 to 6 days. Although SB is eliminated exclusively in the feces, less than 3% of the dose is recovered as viable yeast. When rats were treated with neomycin, which is active against gram-negative aerobic bacteria but not against anaerobes, no change was observed in recovery of SB when compared with recovery from untreated rats. Also, there was no change in the rate at which SB concentrations declined in feces. In contrast, treatment with clindamycin and the broad-spectrum antibiotic ampicillin, which are active against anaerobes, produced an increase in the recovery of SB of up to seven times that of controls and slowed the rate of decline of SB concentration in the feces. This antibiotic effect on SB disposition was also found when SB was administered in multiple doses. An eightfold increase in the steady-state output of SB was observed from ampicillin-treated animals. Analysis of the recovery and kinetic data showed that the primary effect of these antibiotics was to reduce the destruction of SB, probably in the cecum and colon.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of live Saccharomyces cerevisiae cells as a biological response modifier in experimental infections

A short-term oral administration of live Saccharomyces cerevisiae cells, strain Sillix Hansen DSM 1883, resulted in enhanced resistance of mice toward infections with K. pneumoniae. S. pneumoniae and S. pyogenes A produced by intranasal inoculation. Yeast pre-treatment also increased the efficacy of antibiotic therapy in bacterial infections and of antiviral drugs in viral infections. Yeast treatment of animals stimulated phagocytosis, activated the complement system and induced interferon which are likely to represent the main mechanisms of action whereby pretreatment of mice with live S. cerevisiae cells increases resistance to infection. It is concluded that preventive administration of live Saccharomyces cerevisiae cells should be used for increasing resistance to bacterial infections, in particular of the respiratory tract, or to viral infections, as well as an adjunct to antibiotic and antiviral drug therapy.

Prevention of further recurrences of Clostridium difficile colitis with Saccharomyces boulardii

A patient with six documented episodes of recurrent Clostridium difficile colitis over an eight-month period is described. Relapses of colitis occurred despite treatment with vancomycin, metronidazole, bacitracin, and cholestyramine. Each recurrence appeared to begin successively closer to the end of the previous course of treatment. Four episodes were sufficiently severe to require hospitalization for rehydration. Saccharomyces boulardii, a nonpathogenic yeast, was begun prior to discontinuing vancomycin therapy for the last recurrence and was continued for three months. Serial stool cultures and assays for C. difficile showed persistence of the organism but rapid reduction of high titers of cytotoxin. No further recurrences of diarrhea or colitis were encountered while the patient was taking Saccharomyces boulardii and for 18 months of follow-up after the yeast was discontinued.

The influence of the normal flora on Clostridium difficile colonisation of the gut

The normal stable flora of the gut of man and other adult animal species provides an effective barrier to infection by Clostridium difficile. Attempts to understand this mechanism have involved continuous flow and batch culture systems and colonisation of antibiotic pre-treated or germ free animals with gut flora from the same or unrelated species. In general attempts to re-create the barrier effect with the whole caecal or faecal flora have been successful both in vitro and in vivo, whereas attempts using components of that flora have not. The most recent developments in these types of studies have been studies aimed at understanding the mechanisms involved. Preliminary findings imply competition for various monosaccharides, especially those released from mucin, may be important.

Stimulation of secretory IgA and secretory component of immunoglobulins in small intestine of rats treated with Saccharomyces boulardii

Saccharomyces boulardii (S.b.) is largely used in Western European countries for the treatment of acute infectious enteritis and antibiotic-induced gastrointestinal disorders. To study the mechanisms of the protective effect of S.b. against enteral pathogen infection, we assessed the response of the intestinal secretion of secretory IgA (s-IgA) and of the secretory component of immunoglobulins (SC) to oral administration of high doses (0.5 mg/g body weight, three times per day) of S.b. cells in growing rats. S.b. cells (biological activity: 2.8 x 10(9) viable cells/100 mg) were administered daily by gastric intubation to weanling rats from day 14 until day 22 postpartum. Control groups received either 0.9% saline or ovalbumin following the same schedule. Expressed per milligram of cell protein, SC content was significantly increased in crypt cells isolated from the jejunum (48.5% vs saline controls, P less than 0.05) as it was in the duodenal fluid (62.8% vs saline controls, P less than 0.01) of rats treated with S.b. Oral treatment with S.b. had no effect on the secretion of SC by the liver. In the duodenal fluid of rats treated with S.b. cells, the mean concentration of s-IgA was increased by 56.9% (P less than 0.01) over the concentration of s-IgA measured in saline controls.(ABSTRACT TRUNCATED AT 250 WORDS)