Comparative study of Bifidobacterium animalis, Escherichia coli, Lactobacillus casei and Saccharomyces boulardii probiotic properties

Evaluation of the Treatment with Akkermansia muciniphila BAA-835 of Chemotherapy-induced Mucositis in Mice

Mucositis is a high-incidence side effect in cancer patients undergoing chemotherapy. Next-generation probiotics are emerging as new therapeutic tools for managing various disorders. Studies have demonstrated the potential of Akkermansia muciniphila to increase the efficiency of anticancer treatment and to mitigate mucositis. Due to the beneficial effect of A. muciniphila on the host, we evaluated the dose-response, the microorganism viability, and the treatment protocol of A. muciniphila BAA-835 in a murine model of chemotherapy-induced mucositis. Female Balb/c mice were divided into groups that received either sterile 0.9% saline or A. muciniphila by gavage. Mucositis was induced using a single intraperitoneal injection of 5-fluorouracil. The animals were euthanized three days after the induction of mucositis, and tissue and blood were collected for analysis. Prevention of weight loss and small intestine shortening and reduction of neutrophil and eosinophil influx were observed when animals were pretreated with viable A. muciniphila at 1010 colony-forming units per mL (CFU/mL). The A. muciniphila improved mucosal damage by preserving tissue architecture and increasing villus height and goblet cell number. It also improved the integrity of the epithelial barrier, decreasing intestinal permeability and bacterial translocation. In addition, the treatment prevented the expansion of Enterobacteriaceae. The immunological parameters were also improved by decreasing the expression of pro-inflammatory cytokines (IL6, IL1β, and TNF) and increasing IL10. In conclusion, pretreatment with 1010 CFU/mL of viable A. muciniphila effectively controlled inflammation, protected the intestinal mucosa and the epithelial barrier, and prevented Enterobacteriaceae expansion in treated mice.

Single bacteria identification with second-harmonic generation in MoS2

Transition-metal dichalcogenides exhibit extraordinary optical nonlinearities, making them promising candidates for advanced photonic applications. Here, we present the microbial control over second-harmonic generation (SHG) in monolayer MoS2 and the identification of single-cell bacteria. Bacteria deposited on monolayer MoS2 induce a change in the SHG signal, in the form of anisotropic polarization responses that depend on the relative orientation of the bacteria with respect to the MoS2 crystallographic direction. The anisotropic enhancement is consistent with the presence of a tensile stress along the lateral direction of bacteria axis; SHG imaging is highly effective in monitoring biomaterial strain as low as 0.1%. We also investigate the ultraviolet-induced removal of single bacteria, through the SHG imaging of MoS2. By monitoring the transient SHG signals, we determine the rupture times for bacteria, which varies noticeably for each species. This allows us to distinguish specific bacteria that share habitats; SHG imaging is useful for label free identification of pathogens at the single cell levels such as E. coli and L. casei. This label-free detection and identification of pathogens at the single-cell level can have a profound impact on the development of diagnostic tools for various applications.

In Vitro Evaluation of the Technological and Probiotic Potential of Pichia kudriavzevii Strains Isolated from Traditional Fermented Foods

The isolation of endogenous yeast strains from traditionally fermented food products to use as functional starter cultures has become more popular for improved food safety, quality, and beneficial health effects. In this study, 107 Pichia kudriavzevii strains were isolated from sourdough, shalgam, tarhana, artisanal Tulum cheese, and yogurt. The strains were identified by DNA fingerprinting using iPBS-PCR method before technological and probiotic characterization. The multivariate statistical approach revealed that five strains were most promising in terms of technological characterization, including different harsh growth conditions. These strains were also examined in terms of probiotic properties with a commercial S. cerevisiae var boulardii MYA-796 strain. The multivariate statistical analyses indicated that P. kudriavzevii 5S5 were most promising in in vitro probiotic properties such as surviving in human GI conditions, adhering to intestinal cell lines, and exhibiting high hydrophobicity. Therefore, it seems to be a great starter candidate for the production of functional fermented food products.

Saccharomyces cerevisiae boulardii accelerates intestinal microbiota maturation and is correlated with increased secretory IgA production in neonatal dairy calves

Neonatal calves have a limited capacity to initiate immune responses due to a relatively immature adaptive immune system, which renders them susceptible to many on-farm diseases. At birth, the mucosal surfaces of the intestine are rapidly colonized by microbes in a process that promotes mucosal immunity and primes the development of the adaptive immune system. In a companion study, our group demonstrated that supplementation of a live yeast probiotic, Saccharomyces cerevisiae boulardii (SCB) CNCM I-1079, to calves from birth to 1 week of age stimulates secretory IgA (sIgA) production in the intestine. The objective of the study was to evaluate how SCB supplementation impacts the intestinal microbiota of one-week-old male calves, and how changes in the bacterial community in the intestine relate to the increase in secretory IgA. A total of 20 calves were randomly allocated to one of two treatments at birth: Control (CON, n = 10) fed at 5 g/d of carrier with no live yeast; and SCB (n = 10) fed at 5 g of live SCB per day (10 × 109 CFU/d). Our study revealed that supplementing calves with SCB from birth to 1 week of age had its most marked effects in the ileum, increasing species richness and phylogenetic diversity in addition to expediting the transition to a more interconnected bacterial community. Furthermore, LEfSe analysis revealed that there were several differentially abundant taxa between treatments and that SCB increased the relative abundance the family Eubacteriaceae, Corynebacteriaceae, Eggerthellaceae, Bacillaceae, and Ruminococcaceae. Furthermore, network analysis suggests that SCB promoted a more stable bacterial community and appears to reduce colonization with Shigella. Lastly, we observed that the probiotic-driven increase in microbial diversity was highly correlated with the enhanced secretory IgA capacity of the ileum, suggesting that the calf's gut mucosal immune system relies on the development of a stable and highly diverse microbial community to provide the necessary cues to train and promote its proper function. In summary, this data shows that supplementation of SCB promoted establishment of a diverse and interconnected microbiota, prevented colonization of Escherichia Shigella and indicates a possible role in stimulating humoral mucosal immunity.

Understanding the Connection between Gut Homeostasis and Psychological Stress

Long-term exposure to adverse life events that provoke acute or chronic psychological stress (hereinafter "stress") can negatively affect physical health and even increase susceptibility to psychological illnesses, such as anxiety and depression. As a part of the hypothalamic-pituitary-adrenal axis, corticotropin-releasing factor (CRF) released from the hypothalamus is primarily responsible for the stress response. Typically, CRF disrupts the gastrointestinal system and leads to gut microbiota dysbiosis, thereby increasing risk of functional gastrointestinal diseases, such as irritable bowel syndrome. Furthermore, CRF increases oxidative damage to the colon and triggers immune responses involving mast cells, neutrophils, and monocytes. CRF even affects the differentiation of intestinal stem cells (ISCs), causing enterochromaffin cells to secrete excessive amounts of 5-hydroxytryptamine (5-HT). Therefore, stress is often accompanied by damage to the intestinal epithelial barrier function, followed by increased intestinal permeability and bacterial translocation. There are multi-network interactions between the gut microbiota and stress, and gut microbiota may relieve the effects of stress on the body. Dietary intake of probiotics can provide energy for ISCs through glycolysis, thereby alleviating the disruption to homeostasis caused by stress, and it significantly bolsters the intestinal barrier, alleviates intestinal inflammation, and maintains endocrine homeostasis. Gut microbiota also directly affect the synthesis of hormones and neurotransmitters, such as CRF, 5-HT, dopamine, and norepinephrine. Moreover, the Mediterranean diet enhances the stress resistance to some extent by regulating the intestinal flora. This article reviews recent research on how stress damages the gut and microbiota, how the gut microbiota can improve gut health by modulating injury due to stress, and how the diet relieves stress injury by interfering with intestinal microflora. This review gives insight into the potential role of the gut and its microbiota in relieving the effects of stress via the gut-brain axis.

Bioprospecting of the probiotic potential of yeasts isolated from a wine environment

Autochthonous yeasts of oenological origin are adapted to highly stressful and selective environments, which makes them potential candidates for probiotics. The objective of the present study was to explore the probiotic potential of 96 native yeasts of oenological origin, their biosafety, resistance to gastrointestinal tract conditions and adhesion properties. Regarding biosafety, 66 isolates shown negative hemolytic activity, negative urease activity and susceptibility to 3 or more antifungals. After the gastrointestinal resistance test, 15 isolates were selected that showed growth at different temperatures, tolerance to low pH and the presence of bile salts in in vitro tests. In general, survival after simulated conditions of the gastrointestinal tract was high and more restrictive was the duodenal. The results of the adhesion properties showed highly variable hydrophobicity and a high percentage of autoaggregation at 24 h. The maximum production of biofilm was detected in the Pichia strains. Of a total of 96 yeast strains, 15 non-Saccharomyces yeasts presented suitable properties as probiotic candidates. The native winemaking strains performed better than the reference probiotic strain, Saccharomyces cerevisiae var. boulardii CNCM I-745, which reaffirms that these strains are promising probiotic candidates and further studies are necessary to confirm their probiosis.

How do intestinal probiotics restore the intestinal barrier?

The intestinal barrier is a structure that prevents harmful substances, such as bacteria and endotoxins, from penetrating the intestinal wall and entering human tissues, organs, and microcirculation. It can separate colonizing microbes from systemic tissues and prevent the invasion of pathogenic bacteria. Pathological conditions such as shock, trauma, stress, and inflammation damage the intestinal barrier to varying degrees, aggravating the primary disease. Intestinal probiotics are a type of active microorganisms beneficial to the health of the host and an essential element of human health. Reportedly, intestinal probiotics can affect the renewal of intestinal epithelial cells, and also make cell connections closer, increase the production of tight junction proteins and mucins, promote the development of the immune system, regulate the release of intestinal antimicrobial peptides, compete with pathogenic bacteria for nutrients and living space, and interact with the host and intestinal commensal flora to restore the intestinal barrier. In this review, we provide a comprehensive overview of how intestinal probiotics restore the intestinal barrier to provide new ideas for treating intestinal injury-related diseases.

Protective Effect of Bifidobacterium lactis JYBR-190 on Intestinal Mucosal Damage in Chicks Infected With Salmonella pullorum

Pullorum is one of the most serious diseases that endanger the chicken industry. With the advent of the era of anti-antibiotics in feed, the replacement of antibiotics by probiotics has become the focus and hotspot of related research. In this study, hematoxylin-eosin (H&E) staining, immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA) were used to observe the structural changes of intestinal mucosa in chicks infected with Salmonella pullorum, and to analyze TNF-α, IL-10, IFN-γ, proliferating cell nuclear antigen (PCNA), and secreted immunoglobulin A (sIgA) levels. The results showed that the intestinal villus height, villus height to crypt depth ratio (V/C), and muscle layer thickness of duodenum, jejunum and cecum in the JYBR-190 group were significantly higher than those of the infection group and antibiotic group. Furthermore, the levels of PCNA, sIgA and IL-10 in JYBR-190 group were significantly increased, whereas the expression of TNF-α and IFN-γ was significantly decreased. Taken together, Bifidobacterium lactis JYBR-190 has a protective effect on intestinal mucosal damage in chicks infected with Salmonella pullorum.

Study of potential probiotic and biotechnological properties of non-Saccharomyces yeasts from fruit Brazilian ecosystems

Yeast isolates from flowers and fruits from a Brazilian forest were studied. The yeasts were identified at species and strain level by PCR-RFLP and PCR-RAPD, respectively. The 46 isolated yeasts were classified into 11 different species belonging to the genera Candida, Diutina, Hanseniaspora, Meyerozyma, Pichia, Rhodotorula, and Torulaspora. A total of 20 different strains were found. In order to ascertain the probiotic potential, the resistance to gastrointestinal conditions, autoaggregation, and hydrophobicity assays were studied, along with the capacity to form biofilm. The results indicate that, although most of the strains presented better results than Saccharomyces boulardii (the only strain recognized as a probiotic yeast), four strains were the most promising, namely, Rhodotorula mucilaginosa 32, Meyerozyma caribbica 35, and Diutina rugosa 12 and 45, according to the Duncan test. Several biotechnological properties were evaluated. D. rugosa inhibited Dekkera bruxellensis. The assimilation or fermentation of seven sugars was tested, and only five of the yeasts did not show a capacity to assimilate any of the sugars under aerobic conditions. However, all strains were able to ferment at least one of the sugars under anaerobic conditions. As far as enzyme production is concerned, positive results were only found for the enzymes' amylase, pectinase, and protease. D. rugosa 42 and Hanseniaspora opuntiae 18, followed of Pichia kluyveri 26, showed high values for the production of melatonin. In conclusion, the results of this study show that several non-Saccharomyces present probiotic characteristics, and these have good potential for industrial applications in the food or biotechnology industries.

Health-promoting properties of Saccharomyces cerevisiae var. boulardii as a probiotic; characteristics, isolation, and applications in dairy products

Saccharomyces cerevisiae var. boulardii (S. boulardii) has been isolated from lychee (Litchi chinensis), mangosteen fruit, kombucha, and dairy products like kefir. Dairy products containing S. boulardii have been revealed to possess potential probiotic activities owing to their ability to produce organic acids, essential enzymes, vitamins, and other important metabolites such as vanillic acid, phenyl ethyl alcohol, and erythromycin. S. boulardii has a wide spectrum of anti-carcinogenic, antibacterial antiviral, and antioxidant activity, and is known to reduce serum cholesterol levels. However, this yeast has mainly been prescribed for prophylaxis treatment of gastrointestinal infectious diseases, and stimulating the immune system in a number of commercially available products. The present comprehensive review article reviews the properties of S. boulardii related to their use in fermented dairy foods as a probiotic microorganism or starter culture. Technical aspects regarding the integration of this yeast into the dairy foods matrix its health advantages, therapeutic functions, microencapsulation, and viability in harsh conditions, and safety aspects are highlighted.

The Enhancement of Intestinal Immunity in Offspring Piglets by Maternal Probiotic or Synbiotic Supplementation Is Associated With the Alteration of Gut Microbiota

A total of 64 pregnant Bama mini-pigs were used to investigate the effects of maternal probiotic or synbiotic supplementation during gestation and lactation on immune response, intestinal morphology, and microbiota community of offspring piglets. The sows were assigned randomly to one of four groups, control group (basal diet), antibiotic group (basal diet supplemented with 50 g/t virginiamycin), probiotic group (basal diet supplemented with 200 mL/d probiotic fermentation broth per pig), or synbiotic group (basal diet supplemented with 200 mL/d probiotic fermentation broth per pig + 500 g/t xylo-oligosaccharides) during pregnancy and lactation periods. After weaning, two piglets close to the average body weight (BW) per litter were selected and fed a basal diet. Eight piglets with similar BW were selected from each group for sample collection at 65 d-old. The results showed that plasma interleukin (IL)-2 and lipopolysaccharide concentrations were decreased (P < 0.05) in the probiotic group, while the immunoglobulin A (IgA) concentration in the probiotic and synbiotic groups was increased (P < 0.05), when compared with the control group. The jejunal IL-10, interferon-α, and secretory IgA (sIgA) concentrations were increased (P < 0.05) in the probiotic and synbiotic groups, as well as the ileal sIgA concentration in the probiotic group. The jejunal villus height (VH) and the ratio of VH to crypt depth were increased (P < 0.05) in the probiotic group, as well as the ileal VH in the synbiotic group. Furthermore, the piglets from the antibiotic group exhibited a lower microbiota diversity in the jejunum and ileum. The piglets from the synbiotic group had higher relative abundances of Actinobacteria, Bifidobacterium, Turicibacter, and Clostridium in the jejunum compared with the antibiotic group. Dietary probiotic treatment increased (P < 0.05) the relative abundance of Psychrobacter in the ileum compared with the antibiotic and control groups. Spearman's correlation analysis revealed that the relative abundances of Bifidobacterium, Clostridium, and Blautia in the jejunum and Psychrobacter in the ileum, were positively correlated with the alterations of immunoglobulin and cytokines. Collectively, these findings suggest that maternal interventions with probiotic or synbiotic are promising strategies for improving the immune response of offspring piglets by altering the gut microbiota.

Probiotic infant cereal improves children's gut microbiota: Insights using the Simulator of Human Intestinal Microbial Ecosystem (SHIME®)

Infant́s gut microbiota can be modulated by many factors, including mode of delivery, feeding regime, maternal diet/weight and probiotic and prebiotic consumption. The gut microbiota in dysbiosis has been associated with innumerous diseases. In this sense, early childhood intestinal microbiome modulation can be a strategy for disease prevention. This study had the purpose to evaluate the effect of an infant cereal with probiotic (Bifidobacterium animalis ssp. lactis BB-12®) on infant́s intestinal microbiota using SHIME®, which simulates human gastrointestinal conditions. The ascending colon was inoculated with fecal microbiota from three children (2-3 years old). NH₄⁺, short chain fatty acids (SCFASs) and microbiota composition were determined by selective ion electrode, GC/MS and 16S sequencing, respectively. After treatment, butyric acid production increased (p < 0.05) 52% and a decrease in NH₄⁺ production was observed (p < 0.01). The treatment stimulated an increase (p < 0.01) of Lactobacillaceae families, more precisely L. gasseri and L. kefiri. L. gasseri has been associated with the prevention of allergic rhinitis in children and L. kefiri in the prevention of obesity. Thus, infant cereal with BB-12® is able to stimulate the growth of L. gasseri and L. kefiri in a beneficial way, reducing NH₄⁺ and increasing the production of SCFAs, especially butyric acid, in SHIME®.

Role of probiotics in prevention and treatment of enteric infections: a comprehensive review

Microorganisms that inhabits human digestive tract affect global health and enteric disorders. Previous studies have documented the effectiveness and mode of action of probiotics and classified as human-friendly biota and a competitor to enteric pathogens. Statistical studies reported more than 1.5 billion cases of gastrointestinal infections caused by enteric pathogens and their long-term exposure can lead to mental retardation, temporary or permanent physical weakness, and leaving the patient susceptible for opportunistic pathogens, which can cause fatality. We reviewed previous literature providing evidence about therapeutic approaches regarding probiotics to cure enteric infections efficiently by producing inhibitory substances, immune system modulation, improved barrier function. The therapeutic effects of probiotics have shown success against many foodborne pathogens and their therapeutic effectiveness has been exponentially increased using genetically engineered probiotics. The bioengineered probiotic strains are expected to provide a better and alternative approach than traditional antibiotic therapy against enteric pathogens, but the novelty of these strains also raise doubts about the possible untapped side effects, for which there is a need for further studies to eliminate the concerns relating to the use and safety of probiotics. Many such developments and optimization of the classical techniques will revolutionize the treatments for enteric infections.

Intake of Lactobacillus delbrueckii (pExu:hsp65) Prevents the Inflammation and the Disorganization of the Intestinal Mucosa in a Mouse Model of Mucositis

5-Fluorouracil (5-FU) is an antineoplastic drug that causes, as a side effect, intestinal mucositis, acute inflammation in the small bowel. The Heat Shock Protein (Hsp) are highly expressed in inflammatory conditions, developing an important role in immune modulation. Thus, they are potential candidates for the treatment of inflammatory diseases. In the mucositis mouse model, the present study aimed to evaluate the beneficial effect of oral administration of milk fermented by Lactobacillus delbrueckii CIDCA 133 (pExu:hsp65), a recombinant strain. This approach showed increased levels of sIgA in the intestinal fluid, reducing inflammatory infiltrate and intestinal permeability. Additionally, the histological score was improved. Protection was associated with a reduction in the gene expression of pro-inflammatory cytokines such as Tnf, Il6, Il12, and Il1b, and an increase in Il10, Muc2, and claudin 1 (Cldn1) and 2 (Cldn2) gene expression in ileum tissue. These findings are corroborated with the increased number of goblet cells, the electronic microscopy images, and the reduction of intestinal permeability. The administration of milk fermented by this recombinant probiotic strain was also able to reverse the high levels of gene expression of Tlrs caused by the 5-FU. Thus, the rCIDCA 133:Hsp65 strain was revealed to be a promising preventive strategy for small bowel inflammation.

Isolation of Yeasts from Guajillo Pepper (Capsicum annuum L.) Fermentation and Study of Some Probiotic Characteristics

Three yeast strains were isolated from the spontaneous fermentation of guajillo pepper: Hanseniaspora opuntiae, Pichia kudriavzevii, and Wickerhamomyces anomalus, which were identified by amplification of the ITS/5.8S ribosomal DNA. Some probiotic characteristics of these strains were evaluated and compared with one commercial probiotic yeast (Saccharomyces boulardii). The survival percentage of all the yeasts was similar to that of the commercial product. They showed different hydrophobicity characteristics with hydrocarbons, autoaggregation > 90%, and characteristics of co-aggregation with pathogenic microorganisms. The adhesion capacity to mucin of the three yeast samples was similar to the reference yeast. The antioxidant activity of the yeasts varied between 155 and 178 μM Trolox equivalents. All exhibited cholesterol reduction capacity, and W. anomalus was able to decrease up to 83% of cholesterol after 48 h of incubation. The 7.5-fold concentrated H. opuntiae supernatant had antimicrobial activity against Salmonella enterica ser. Typhimurium ATCC 14028 and Candida albicans ENCBDM2; tests suggest this activity against S. Typhimurium is due to a proteinaceous metabolite with a weight between 10 and 30 kDa. Among the yeasts, P. kudriavzevii exhibited the highest protective effect on the viability of Lactobacillus casei Shirota in gastric and intestinal conditions. These results suggest that yeasts isolated from guajillo pepper may have a probiotic potential.

Influence of skin wounds on the intestinal inflammatory response and barrier function: Protective role of dietary Shewanella putrefaciens SpPdp11 administration to gilthead seabream (Sparus aurata L.)

The effects of skin wounds on the intestinal barrier function and the beneficial effects of the dietary administration of Shewanella putrefaciens (known as SpPdp11) in gilthead seabream (Sparus aurata L.) were studied. Two replicates of fish were fed a commercial diet (control, CON) or CON diet enriched with 10⁹ cfu g^-1 SpPdp11 (SP diet) for 30 days. After this time, half of the fish were sampled, while the others were injured below the lateral line (wounded fish, W) and fed the same diets for an extra week before sampling (CON + W and SP + W groups). The intestinal histology and gene expression of different genes relevant for the intestinal barrier function were studied. The results showed that injured fish had a disordered enterocyte nucleus disposition, a more intense infiltration of mixed leucocytes and a thicker lamina propria in the intestine compared to the control fish. However, the fish in the SP + W group did not present these pathological symptoms in the intestine. No significant variations in the number of goblet cells were detected among the different experimental groups. Pro-inflammatory cytokines (colony-stimulating factor receptor 1, CSF1R, myeloperoxidase, MPO and interleukin-1β, IL-1β), mucins (intestinal mucin, IMUC and mucin 2, MUC2), and immunoglobulin T heavy chain (IGHT) were up-regulated, while tight junction protein occludin was down-regulated in the intestine from fish of the CON + W group. Similarly, the dietary administration of SpPdp11 markedly depressed the gene expression of pro-inflammatory cytokines, MUC2 and IGHT, but increased the gene expression of anti-inflammatory cytokine transforming growth factor-β1 (TGF-β1) and the tight junction proteins tricellulin and occluding after wounding. In brief, the skin wounds provoked an intestinal inflammatory response that included changes in the mucus layer and tight junction disruptions. Besides this, preventive administration of SpPdp11 alleviated the intestinal dysfunctions caused by skin wounds in gilthead seabream.

The Influence of Feed-Supplementation with Probiotic Strain Lactobacillus reuteri CCM 8617 and Alginite on Intestinal Microenvironment of SPF Mice Infected with Salmonella Typhimurium CCM 7205

Alginite is a non-ore raw material arising by fossilization of accumulated organic (algae) and inorganic material, particularly clay, carbonates, quartz, and amorphous modification of silicic acid in the aqueous environment. Humic acids as a component of organic portion of alginite are known for very good buffering ability which allows them to stabilise pH throughout the digestion system of animals, stimulate receptors of the immune system in intestinal villi against pathogenic bacteria, and support proliferation and activity of beneficial bacteria (lactobacilli, bifidobacteria, and similar). Our investigations focused on the influence of a probiotic strain in combination with alginite on intestinal microenvironment of SPF mice infected with Salmonella Typhimurium. The 66 female mice (BALB/c) used in our study were divided to four experimental groups, control NC1, control NC2 (alginite), IC (alginite + Salmonella Typhimurium CCM 7205_NAL), LAB (Lact. reuteri CCM 8617 + alginite + Salm. Typhimurium CCM 7205_NAL). The group supplemented with Lact.reuteri CCM 8617 and alginite showed significant reduction in growth of Salm. Typhimurium in mice faeces at 24 and 72 h (P < 0.001) post infection. The supplementation of additives affected positively also nitrogen, enzymatic, hepatic and energy metabolism of mice. The demonstrable positive influence of additives alleviated the negative impact of Salm. Typhimurium infection on the morphology investigated in the jejunum and ileum of LAB group of mice. The livers of mice treated with both alginite and Lact.reuteri CCM 8617 showed marked reduction of overall inflammation, hepatocyte necrosis and size of typhoid nodules.

Yeasts isolated from Brazilian fermented foods in the protection against infection by pathogenic food bacteria

The consumption of probiotics has increased due to the reported health benefits, mainly in preventing or treating gastrointestinal pathology. This study investigated the antimicrobial capacity of yeasts, Saccharomyces cerevisiae and Pichia kluyveri, previously isolated from fermented foods (indigenous beverage, kefir and cocoa) against the adhesion of foodborne pathogens to Caco-2 cells. Co-aggregation of yeasts with pathogens and were evaluated by quantitative analysis and using scanning electron and laser confocal microscopies. All yeasts strains were able to co-aggregate with the tested pathogens, however, this activity was strain-dependent. The inhibition tests showed that the adhesion of Escherichia coli EPEC, Listeria monocytogenes and Salmonella Enteritidis to Caco-2 was reduced by all the yeasts studied. Most of the evaluated yeasts showed inhibition rates equal to or greater than the commercial probiotic Saccharomyces boulardii. The yeasts were able to reduce up to 50% of the bacterial infection, as observed for CCMA0615 towards EPEC in exclusion assay; CCMA0731, CCMA0732 and CCMA0615 towards L. monocytogenes in exclusion and competition assays; and CCMA0731 in exclusion and CCMA0731, CCMA0732, CCMA0615 in competition assay towards S. Enteritidis. No antimicrobial compounds were produced by the yeasts, showing that competition for nutrients and/or receptors in the intestinal mucosa was the mechanism to bacterial inhibition.

Positive effects of dietary supplementation of three probiotics on milk yield, milk composition and intestinal flora in Sannan dairy goats varied in kind of probiotics

In this study, we investigated the effects of Saccharomyces cerevisiae (SC), Bacillus subtilis (BS) and Enterococcus faecalis (EF), singly and in combination, on the dry matter intake (DMI), milk production and composition, and faecal microflora of Saanen dairy goats. Fifty goats were randomly divided into five groups: (a) basal diet (control); (b) basal diet + SC; (c) basal diet + BS; (d) basal diet + EF; and (e) basal diet + mixed probiotics. Each treated animal received 5 g/d of probiotics for a total administration of 5 × 1,011 CFU/goat per day. The inclusion of B. subtilis and E. faecalis in the diet of lactating Saanen goats increased DMI (p < .05). Enhanced milk yield was observed with BS and EF. Milk fat percentage was significantly increased by feeding mixed probiotics compared with the control (p < .05); supplying SC, BS and mixed probiotics enhanced the protein percentage (p < .05). The milk lactose percentage in the SC and BS groups was higher than in the control (p < .05). The amount of milk total solids was higher after feeding EF or mixed probiotics than in the control group (p < .05). Non-fat solids showed no notable differences among groups (p > .05). There was no significant influence on gut bacterial abundance and diversity from adding these three probiotics, singly or in combination. Bacteroidales, Escherichia-Shigella and Christensenellaceae abundances were decreased by supplying these probiotics but Succinivibrionaceae increased. In conclusion, there were positive influences of probiotic feed supplementation on intake, milk performance and intestinal microecology.

Lactobacillus casei DBN023 protects against jejunal mucosal injury in chicks infected with Salmonella pullorum CMCC-533

Pullorum disease is one of the most serious poultry diseases. Antibiotic prophylaxis is commonly applied in actual production, but the emergence of drug-resistant strains and drug residues threatens the health of animals and humans. The use of probiotics has become a potential solution for the aforementioned problem. In this study, we investigated the effects of Lactobacillus casei DBN023 (CGMCC-16146) on the intestinal tissue structure and immune functions of the jejunal epithelium in chicks infected with Salmonella pullorum CMCC-533 using histomorphological and immunological methods. A total of 450 newborn chicks were randomly divided into the control group and experimental groups. We used hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC), and an enzyme-linked immunosorbent assay (ELISA) to observe the structure of the jejunal mucosa and analyze changes in cytokine and secretory immunoglobulin A (sIgA) levels. The results showed that prophylactic feeding of L. casei DBN023 to chicks significantly increased their jejunum villar height, villar height-to-crypt-depth (V/C) ratio, and muscle thickness; reduced intestinal-crypt depth; and increased the proliferating cell nuclear antigen (PCNA) level compared with S. pullorum infection. L. casei DBN023 enhances intestinal mucosal immunity, regulates cytokine balance, enhances intestinal immune function, and effectively reduces intestinal inflammation. Thus, it protects intestinal tissues and reduces S. pullorum CMCC-533 damage to the intestinal tract.

Therapeutic effect of Saccharomyces boulardii combined with Bifidobacterium and on cellular immune function in children with acute diarrhea

Clinical effect of Saccharomyces boulardii combined with bifidobacterium and its effect on cellular immune function in children with acute diarrhea were studied. In total 116 cases of children with acute diarrhea admitted to Xuzhou Children's Hospital from March 2015 to March 2017 were collected and analyzed retrospectively. There were 59 children treated with Saccharomyces boulardii as control group and 57 children treated with Saccharomyces boulardii combined with bifidobacterium as experimental group. The clinical effect, stool frequency in different time periods, mean antidiarrheal time, mean antipyretic time and length of stay, and immune function of children in the two groups after treatment were analyzed. The cure rate (73.68%) and the total effective rate (87.72%) in the experimental group were significantly higher than those in the control group (47.46 and 71.19%) (P<0.05). The stool frequency in the experimental group was significantly lower than that in the control group 3 days after treatment (P<0.05). The mean antidiarrheal time in the experimental group was significantly shorter than that in the control group (P<0.05). The length of stay in the control group was significantly longer than that in the experimental group (P<0.05). CD3+, CD4+ and CD4+/CD8+ increased significantly in the experimental group after treatment while CD8+ decreased significantly (P<0.05). After treatment, the ratio of Th1 and Th2 in the two groups decreased significantly compared with before treatment (P<0.05), and the experimental group was significantly lower than the control group (P<0.05). After treatment, Th1/Th2 ratio was significantly higher than that before treatment (P<0.05), and the experimental group was significantly higher than the control group (P<0.05). In conclusion, treatment of acute diarrhea in children with Saccharomyces boulardii combined with bifidobacterium can effectively shorten the duration of diarrhea and hospital stay, reduce the number of diarrhea and enhance the cellular immune function.

Semi-industrial Scale Production of a New Yeast with Probiotic Traits, Cryptococcus sp. YMHS, Isolated from the Red Sea

A new yeast strain with promising probiotic traits was isolated from the Red Sea water samples. The isolate (YMHS) was subjected to genetic characterization and identified as Cryptococcus sp. Nucleotide sequence analysis of the rRNA gene internal transcribed spacer regions showed 95% sequence similarity between the isolate and Cryptococcus albidus. Cryptococcus sp. YMHS exhibited desirable characteristics of probiotic microorganisms; it has tolerance to low pH in simulated gastric juice, resistance to bile salts, hydrophobic characteristics, broad antimicrobial activity, and in vitro ability to degrade cholesterol. The isolate grew well in a semi-defined medium composed of yeast extract, glucose, KH₂PO₄, (NH₄)₂SO₄, and MgSO₄, yielding cell mass of 2.32 and 5.82 g/l in shake flask and in bioreactor cultures, respectively. Fed-batch cultivation, with controlled pH, increased the biomass gradually in culture, reaching 28.5 g/l after 32 h cultivation. Beside the feasible use as a probiotic, the new strain also could be beneficial in the development of functional foods or novel food preservatives. To our knowledge, this is the first report of yeast with probiotic properties isolated from the Red Sea.

Saccharomyces cerevisiae var. boulardii CNCM I-1079 and Lactobacillus acidophilus BT1386 influence innate immune response and serum levels of acute-phase proteins during weaning in Holstein calves

The aims of this study were to investigate the effect of Saccharomyces cerevisiae var. boulardii CNCM I-1079 (SCB) or Lactobacillus acidophilus BT1386 (LA) on (1) innate immune response, (2) markers of acute-phase reaction, and (3) immune gene expression of rumen and ileum tissues of Holstein calves. Forty eight calves (∼5 d old) were randomly allocated to four treatments as follows: (1) control (CTRL) fed milk replacer followed by starter feed, (2) CTRL supplemented with SCB in milk and feed, (3) CTRL supplemented with LA in milk and feed, and (4) CTRL supplemented with antibiotics (ATB; chlortetracycline and neomycin in milk, and chlortetracycline in feed). Tumor necrosis factor α (TNF-α) decreased (P < 0.05) on day 66 (post-weaning) for the ATB-treated calves. There were no treatment effects on production of interferon γ (IFN-γ) and interleukin 6 (IL-6) proteins and on expression of TLR4, TLR6, TLR9, TLR10, CLDN3, MUC1, and MUC20 genes. Calves fed SCB or LA had a greater (P < 0.05) oxidative burst at weaning (day 53) compared with CTRL. Oxidative burst was also greater (P < 0.05) after weaning (day 59 and day 87) for SCB-fed calves. Calves fed SCB and ATB had higher (P < 0.05) phagocytosis activity during weaning (day 47) compared with CTRL. The concentration of serum amyloid A2 (SAA2) increased (P < 0.05) in SCB- and LA-fed calves (day 53), whereas the concentration of C-reactive protein (CRP) increased (P < 0.05) in SCB-fed calves during weaning as compared with CTRL. Our results suggest that SCB could improve innate immune response (oxidative burst and phagocytosis) and markers of acute-phase reaction (CRP and SAA2), especially during critical periods like weaning.

Impact of Edible Cricket Consumption on Gut Microbiota in Healthy Adults, a Double-blind, Randomized Crossover Trial

Edible insects are often considered a nutritious, protein-rich, environmentally sustainable alternative to traditional livestock with growing popularity among North American consumers. While the nutrient composition of several insects is characterized, all potential health impacts have not been evaluated. In addition to high protein levels, crickets contain chitin and other fibers that may influence gut health. In this study, we evaluated the effects of consuming 25 grams/day whole cricket powder on gut microbiota composition, while assessing safety and tolerability. Twenty healthy adults participated in this six-week, double-blind, crossover dietary intervention. Participants were randomized into two study arms and consumed either cricket-containing or control breakfast foods for 14 days, followed by a washout period and assignment to the opposite treatment. Blood and stool samples were collected at baseline and after each treatment period to assess liver function and microbiota changes. Results demonstrate cricket consumption is tolerable and non-toxic at the studied dose. Cricket powder supported growth of the probiotic bacterium, Bifidobacterium animalis, which increased 5.7-fold. Cricket consumption was also associated with reduced plasma TNF-α. These data suggest that eating crickets may improve gut health and reduce systemic inflammation; however, more research is needed to understand these effects and underlying mechanisms.

Lactobacillus frumenti Facilitates Intestinal Epithelial Barrier Function Maintenance in Early-Weaned Piglets

Increased intestinal epithelial barrier function damages caused by early weaning stress have adverse effects on swine health and feed utilization efficiency. Probiotics have emerged as the promising antibiotic alternatives used for intestinal barrier function damage prevention. Our previous data showed that Lactobacillus frumenti was identified as a predominant Lactobacillus in the intestinal microbiota of weaned piglets. However, whether the intestinal epithelial barrier function in piglets was regulated by L. frumenti is still unclear. Here, piglets received a PBS vehicle or PBS suspension (2 ml, 10⁸ CFU/ml) containing the L. frumenti by oral gavage once a day during the period of 6–20 days of age prior to early weaning. Our data demonstrated that oral administration of L. frumenti significantly improved the intestinal mucosal integrity and decreased the serum endotoxin and D-lactic acid levels in early-weaned piglets (26 days of age). The intestinal tight junction proteins (including ZO-1, Occludin, and Claudin-1) were significantly up-regulated by L. frumenti administration. The serum immunoglobulin G (IgG) levels, intestinal secretory immunoglobulin A (sIgA) levels, and interferon-γ (IFN-γ) levels were significantly increased by L. frumenti administration. Furthermore, our data revealed that oral administration of L. frumenti significantly increased the relative abundances of health-promoting microbes (including L. frumenti, Lactobacillus gasseri LA39, Parabacteroides distasonis, and Kazachstania telluris) and decreased the relative abundances of opportunistic pathogens (including Desulfovibrio desulfuricans and Candida humilis). Functional alteration of the intestinal bacterial community by L. frumenti administration was characterized by the significantly increased fatty acids and protein metabolism and decreased diseases-associated metabolic pathways. These findings suggest that L. frumenti facilitates intestinal epithelial barrier function maintenance in early-weaned piglets and may be a promising antibiotic alternative used for intestinal epithelial barrier function damage prevention in mammals.

Saccharomyces cerevisiae-based probiotic as novel anti-fungal and anti-inflammatory agent for therapy of vaginal candidiasis

Previously we demonstrated that the treatment with live Saccharomyces cerevisiae exerts beneficial therapeutic effects against vaginal candidiasis. Here, we address potential mechanisms particularly examining the probiotic capacity to modulate both fungus and host-related factors. We show that the S. cerevisiae-based probiotic markedly affects the expression of virulence traits of Candida albicans such as aspartyl proteinases (SAPs) as well as hyphae-associated proteins Hwp1 and Ece1 in the vaginal cavity. On the host side, the probiotic suppression of the influx of neutrophils caused by the fungus into the vaginas of the mice is likely related to: (1) lower production of interleukin-8; and (2) inhibition of SAPs expression. However, these neutrophils displayed reactive oxygen species hyperproduction and increased killing activity as compared to the neutrophils of placebo-treated mice. There was no evidence of any cytotoxic effect by the probiotic, either when used in vivo on vaginal epithelial cell and organ architecture, or in in vitro in human vaginal epithelium. Inactivated yeast cells did not affect any of the factors above. In summary, the data suggest that the beneficial effect exerted by this S. cerevisiae-based probiotic is the result of its interference with the expression of fungus virulence factors coupled with the modulation of the inflammatory response of the host.

Gleaning Insights from Fecal Microbiota Transplantation and Probiotic Studies for the Rational Design of Combination Microbial Therapies

Beneficial microorganisms hold promise for the treatment of numerous gastrointestinal diseases. The transfer of whole microbiota via fecal transplantation has already been shown to ameliorate the severity of diseases such as Clostridium difficile infection, inflammatory bowel disease, and others. However, the exact mechanisms of fecal microbiota transplant efficacy and the particular strains conferring this benefit are still unclear. Rationally designed combinations of microbial preparations may enable more efficient and effective treatment approaches tailored to particular diseases. Here we use an infectious disease, C. difficile infection, and an inflammatory disorder, the inflammatory bowel disease ulcerative colitis, as examples to facilitate the discussion of how microbial therapy might be rationally designed for specific gastrointestinal diseases. Fecal microbiota transplantation has already shown some efficacy in the treatment of both these disorders; detailed comparisons of studies evaluating commensal and probiotic organisms in the context of these disparate gastrointestinal diseases may shed light on potential protective mechanisms and elucidate how future microbial therapies can be tailored to particular diseases.

Influence of indigenous microbiota on experimental toxoplasmosis in conventional and germ-free mice

Toxoplasmosis represents one of the most common zoonoses worldwide. Its agent, Toxoplasma gondii, causes a severe innate pro-inflammatory response. The indigenous intestinal microbiota promotes host animal homoeostasis and may protect the host against pathogens. Germ-free (GF) animals provide an important tool for the study of interactions between host and microbiota. In this study, we assessed the role of indigenous microorganisms in disease development utilizing a murine toxoplasmosis model, which includes conventional (CV) and GF NIH Swiss mice. CV and GF mice orally inoculated with T. gondii had similar survival curves. However, disease developed differently in the two animal groups. In CV mice, intestinal permeability increased and levels of intestinal pro-inflammatory cytokines were altered. In GF animals, there were discrete epithelial degenerative changes and mucosal oedema, but the liver and lungs displayed significant lesions. We conclude that, despite similar survival curves, CV animals succumb to an exaggerated inflammatory response, whereas GF mice fail to produce an adequate systemic response.

In vivo probiotic and antimicrobial photodynamic therapy as alternative therapies against cryptococcosis are ineffective

Cryptococcosis, an invasive fungal infection distributed worldwide that affects both domestic and wild animals, has incredible rates regarding treatment failure, leading to the necessity of the development of new therapies. In this way, we aimed to evaluate the probiotic (Saccharomyces boulardii, Lactobacillus paracasei ST-11, and Lactobacillus rhamnosus GG) and antimicrobial photodynamic alternative therapies against Cryptococcus gattii in a murine model. Although previous studies suggest that these therapies can be promising against cryptococcosis, our experimental conditions for both probiotic and antimicrobial photodynamic therapies (aPDT) were not able to improve the survival of mice with cryptococcosis, even with the treatment combined with fluconazole. Our results may help other researchers to find the best protocol to test alternative therapies against Cryptococcus gattii.

Saccharomyces cerevisiae from Brazilian kefir-fermented milk: An in vitro evaluation of probiotic properties

The therapeutic use of probiotics for supporting the antibiotic action against gastrointestinal disorders is a current trend and emerging applications have gained popularity because of their support for various microbiological activities in digestive processes. Microorganisms isolated from kefir with great probiotic properties, in addition to high resistance to harsh environmental conditions, have been widely researched. Administration of probiotic yeasts offers a number of advantages, when compared to bacteria, because of particular characteristics as their larger cell size. In the present study, 28 strains of Saccharomyces cerevisiae were isolated, after in vitro digestion of kefir-fermented milk, and identified by molecular based approaches. A screening was performed to determine important quality requirements for probiotics including: antagonistic and antioxidant activities, β-galactosidase synthesis, autoaggregation, surface hydrophobicity and adhesion to epithelial cells. The results showed strains: with antagonistic activity against microbial pathogens such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis; able to produce β-galactosidase; with antioxidant activity levels higher than 90%; with hydrophobicity activity and autoaggregation ability (evaluated by adhesion test, where all the strains presented adhesion to mice ileal epithelial cells). These findings are relevant and the strains are recommended for further in vivo studies as well as for potential therapeutic applications.

Glutamine-Induced Secretion of Intestinal Secretory Immunoglobulin A: A Mechanistic Perspective

Secretory immunoglobulin A (SIgA) is one important line of defense in the intestinal mucosal surface to protect the intestinal epithelium from enteric toxins and pathogenic microorganisms. Multiple factors, such as intestinal microbiota, intestinal cytokines, and nutrients are highly involved in production of SIgA in the intestine. Recently, glutamine has been shown to affect intestinal SIgA production; however, the underlying mechanism by which glutamine stimulates secretion of intestinal SIgA is unknown. Here, we review current knowledge regarding glutamine in intestinal immunity and show that glutamine-enhanced secretion of SIgA in the intestine may involve intestinal microbiota, intestinal antigen sampling and presentation, induction pathways for SIgA production by plasma cells (both T-dependent and T-independent pathway), and even transport of SIgA. Altogether, the glutamine-intestinal SIgA axis has broad therapeutic implications for intestinal SIgA-associated diseases, such as celiac disease, allergies, and inflammatory bowel disease.

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.

Metabolic Engineering of Probiotic Saccharomyces boulardii

Saccharomyces boulardiiis a probiotic yeast that has been used for promoting gut health as well as preventing diarrheal diseases. This yeast not only exhibits beneficial phenotypes for gut health but also can stay longer in the gut than Saccharomyces cerevisiae Therefore, S. boulardiiis an attractive host for metabolic engineering to produce biomolecules of interest in the gut. However, the lack of auxotrophic strains with defined genetic backgrounds has hampered the use of this strain for metabolic engineering. Here, we report the development of well-defined auxotrophic mutants (leu2,ura3,his3, and trp1) through clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9-based genome editing. The resulting auxotrophic mutants can be used as a host for introducing various genetic perturbations, such as overexpression or deletion of a target gene, using existing genetic tools forS. cerevisiae We demonstrated the overexpression of a heterologous gene (lacZ), the correct localization of a target protein (red fluorescent protein) into mitochondria by using a protein localization signal, and the introduction of a heterologous metabolic pathway (xylose-assimilating pathway) in the genome ofS. boulardii We further demonstrated that human lysozyme, which is beneficial for human gut health, could be secreted by S. boulardii Our results suggest that more sophisticated genetic perturbations to improveS. boulardii can be performed without using a drug resistance marker, which is a prerequisite for in vivo applications using engineeredS. boulardii.

Bifidobacterium longum subsp. infantis BB-02 attenuates acute murine experimental model of inflammatory bowel disease

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions, characterised by remissions and relapses episodes, whose main manifestations are ulcerative colitis and Crohn's disease. Ulcerative colitis (UC), one of the main forms of IBD, has as standard treatment the use of corticosteroids and anti-inflammatory drugs. The use of antibiotics has been also reported, but the possible adverse effects, such as disturbance of the indigenous microbiota or resistance induction, should be taken into consideration, and thus the use of probiotics emerges as a possible alternative option of treatment. In this study, the oral administration of Bifidobacterium longum subsp. infantis BB-02 was evaluated as a preventive strategy for acute experimental UC induced in female BALB/c mice by ingestion of 3.5% dextran sulphate sodium in drinking water during 7 days. During this time, the daily disease activity index was evaluated, and on the seventh day the animals were euthanised to collect intestines and liver for analysis. Treatment with the probiotic resulted in clinical improvement of the animals. The histological and morphometric analyses showed a reduction of lesions and oedema in the gut, but there was no increase in the production of mucin. The dosage of secretory immunoglobulin A was significantly higher in the colitis group and reduced in the group treated with the probiotic. There was also a reduction in the inflammation of the colon, as demonstrated by a decrease in neutrophils infiltration, and KC/CXCL-1 levels. The intestinal permeability, which is typically increased during the onset of IBD, was also reduced by treatment with probiotic. Based on these data, it can be concluded that the bacterium B. infantis BB-02 has a probiotic potential for the attenuation of UC, but further studies should be conducted to verify the mechanism of protective action of the bacterium.

Weissella paramesenteroides WpK4 reduces gene expression of intestinal cytokines, and hepatic and splenic injuries in a murine model of typhoid fever

Diarrhoea in piglets by Salmonella and other pathogens can be a serious health problem. Non-drug treatments such as probiotic microorganisms have various effects on the gastrointestinal microbiota dysbiosis and host immune system modulation. The aim of this study was to demonstrate the suitable use of Weissella paramesenteroides WpK4 strain isolated from healthy piglets as an alternative prophylactic or therapeutic treatment against Salmonella Typhimurium. Out of 37 lactic acid bacteria isolates, 24 strains belonging to the Weissella and Lactobacillus genera were analysed in vitro for desirable probiotic characteristics. The W. paramesenteroides WpK4 strain fulfilled all in vitro tests: resistance to acidic pH and bile salts, hydrophobic cell surface, antagonism against bacterial pathogens, H2O2 production and exopolysaccharide secretion, and non-transferable resistance to antibiotics. Mice fed with WpK4 showed no signs of bacterial translocation to the liver or spleen and decreased Salmonella translocation to these organs. Significantly, WpK4 intake attenuated the weight loss, fostered the preservation of intestinal architecture and integrity, and promoted survival in mice following infection with Salmonella Typhimurium. In addition, WpK4 modulated immune cellular response by inhibiting the production of pro-inflammatory cytokines and inducing anti-inflammatory mediators. These findings validate the probiotic properties of W. paramesenteroides WpK4 strain, and its eventual use in piglets.

The Biological Fight Against Pathogenic Bacteria and Protozoa

The animal gastrointestinal tract is a tube with two open ends; hence, from the microbial point of view it constitutes an open system, as opposed to the circulatory system that must be a tightly closed microbial-free environment. In particular, the human intestine spans ca. 200 m² and represents a massive absorptive surface composed of a layer of epithelial cells as well as a paracellular barrier. The permeability of this paracellular barrier is regulated by transmembrane proteins known as claudins that play a critical role in tight junctions.

Microorganisms linked to inflammatory bowel disease-associated dysbiosis differentially impact host physiology in gnotobiotic mice

Studying host-microbiota interactions are fundamental to understanding the mechanisms involved in intestinal homeostasis and inflammation. In this work, we analyzed these interactions in mice that were mono-associated with six microorganisms that are representative of inflammatory bowel disease (IBD)-associated dysbiosis: the bacteria Bacteroides thetaiotaomicron, adhesive-invasive Escherichia coli (AIEC), Ruminococcus gnavus and Roseburia intestinalis; a yeast used as a probiotic drug, Saccharomyces boulardii CNCM I-745; and another yeast, Candida albicans. Extensive ex vivo analyses including colon transcriptomics, histology, immune response, bile acid metabolism and short-chain fatty acid production were studied. We showed that B. thetaiotaomicron had the highest impact on the immune system because it was almost able to recapitulate the effects of the entire conventional microbiota and notably induced Treg pathways. Furthermore, these analyses uncovered the effects of E. coli AIEC LF82 on indoleamine 2,3-dioxygenase expression and of S. boulardii CNCM I-745 on angiogenesis. These results were confirmed in vitro in human cell lines. Finally, our results suggested that R. gnavus has major effects on metabolism, and notably on tryptophan metabolism. This work therefore reveals that microorganisms with a potential role in intestinal homeostasis and inflammation have specific impacts on the host, and it suggests several tracks to follow to understand intestinal homeostasis and IBD pathogenesis better, providing new insights to identify novel therapeutic targets.

Effect of intestinal colonisation by two Lactobacillus strains on the immune response of gnotobiotic mice

The effect of intestinal colonisation on the immune system was investigated in germ-free mice monoassociated with Lactobacillus strains isolated from calf faeces. Single doses of Lactobacillus acidophilus L36 or Lactobacillus salivarius L38 were administered to germ-free mice by intragastric gavage. Ten days later, the mice were euthanised. Gene expression levels of interleukin 5 (IL-5), IL-6, IL-10, IL-12b, IL-17a, gamma interferon (IFN-γ), transforming growth factor beta 1 (TGF-β1), and tumour necrosis factor alpha (TNF-α) were quantified in segments of the small and large intestines by real time quantitative polymerase chain reaction. All the mice were colonised rapidly after Lactobacillus administration with intestinal counts ranging from 6.53 to 8.26 log cfu/g. L. acidophilus L36 administration increased the expression of cytokines involved with the Th2 (IL-5, IL-6 and TGF-β1) and Th17 (IL-17a, TNF-α and IL-6) inflammatory response, whereas L. salivarius L38 appeared to stimulate a pattern of less diversified cytokines in the intestine. Intragastric gavage of L. acidophilus L36 and L. salivarius L38 induced similar levels of colonisation in the digestive tracts of germ-free mice but stimulated different immune responses in the intestinal mucosa. The different immunomodulation patterns might facilitate the potential use of these lactobacilli as probiotics to treat distinct pathological conditions, for example protection against Citrobacter rodentium infection by stimulating IL-17 production.

Functional heterologous protein expression by genetically engineered probiotic yeast Saccharomyces boulardii

Recent studies have suggested the potential of probiotic organisms to be adapted for the synthesis and delivery of oral therapeutics. The probiotic yeast Saccharomyces boulardii would be especially well suited for this purpose due to its ability, in contrast to probiotic prokaryotes, to perform eukaryotic post translational modifications. This probiotic yeast thus has the potential to express a broad array of therapeutic proteins. Currently, however, use of wild type (WT) S. boulardii relies on antibiotic resistance for the selection of transformed yeast. Here we report the creation of auxotrophic mutant strains of S. boulardii that can be selected without antibiotics and demonstrate that these yeast can express functional recombinant protein even when recovered from gastrointestinal immune tissues in mice. A UV mutagenesis approach was employed to generate three uracil auxotrophic S. boulardii mutants that show a low rate of reversion to wild type growth. These mutants can express recombinant protein and are resistant in vitro to low pH, bile acid salts, and anaerobic conditions. Critically, oral gavage experiments using C57BL/6 mice demonstrate that mutant S. boulardii survive and are taken up into gastrointestinal immune tissues on a similar level as WT S. boulardii. Mutant yeast recovered from gastrointestinal immune tissues furthermore retain expression of functional recombinant protein. These data show that auxotrophic mutant S. boulardii can safely express recombinant protein without antibiotic selection and can deliver recombinant protein to gastrointestinal immune tissues. These auxotrophic mutants of S. boulardii pave the way for future experiments to test the ability of S. boulardii to deliver therapeutics and mediate protection against gastrointestinal disorders.

Dietary glutamine prevents the loss of intestinal barrier function and attenuates the increase in core body temperature induced by acute heat exposure

Dietary glutamine (Gln) supplementation improves intestinal function in several stressful conditions. Therefore, in the present study, the effects of dietary Gln supplementation on the core body temperature (T core), bacterial translocation (BT) and intestinal permeability of mice subjected to acute heat stress were evaluated. Male Swiss mice (4 weeks old) were implanted with an abdominal temperature sensor and randomly assigned to one of the following groups fed isoenergetic and isoproteic diets for 7 d before the experimental trials: group fed the standard AIN-93G diet and exposed to a high ambient temperature (39°C) for 2 h (H-NS); group fed the AIN-93G diet supplemented with l-Gln and exposed to a high temperature (H-Gln); group fed the standard AIN-93G diet and not exposed to a high temperature (control, C-NS). Mice were orally administered diethylenetriaminepentaacetic acid radiolabelled with technetium (99mTc) for the assessment of intestinal permeability or 99mTc-Escherichia coli for the assessment of BT. Heat exposure increased T core (approximately 41°C during the experimental trial), intestinal permeability and BT to the blood and liver (3 h after the experimental trial) in mice from the H-NS group relative to those from the C-NS group. Dietary Gln supplementation attenuated hyperthermia and prevented the increases in intestinal permeability and BT induced by heat exposure. No correlations were observed between the improvements in gastrointestinal function and the attenuation of hyperthermia by Gln. Our findings indicate that dietary Gln supplementation preserved the integrity of the intestinal barrier and reduced the severity of hyperthermia during heat exposure. The findings also indicate that these Gln-mediated effects occurred through independent mechanisms.

Safety and protective effectiveness of two strains of Lactobacillus with probiotic features in an experimental model of salmonellosis

Two strains of Lactobacillus, previously isolated from bovine faeces and tested in vitro for properties desired in probiotics, were evaluated for their in vivo effectiveness in protecting against experimental salmonellosis. L. salivarius L38 and L. acidophilus L36 previously demonstrated the ability to successfully colonize the gastrointestinal tract of germ-free mice and stimulate the immune system associated with the intestinal mucosa. L38- or L36-feeding showed no detrimental effect on the general health indicators and did not induce changes in normal architecture of liver and small intestine, indicating that the use of these strains is apparently safe. In control animals fed L38 strain, several cytokines had augmented mRNA levels that can be associated with a homeostatic state of intestinal mucosa, while L36 had less diverse regulation. IgA production and secretion in the intestinal lumen induced by infection was abrogated by pretreating with both lactobacilli. In addition, liver and small intestine histological scores and, translocation of Salmonella cells to liver and spleen, indicated that these strains did not confer protection against the infection. So, the IL-12:IL-18àIFN-g axis, essential for an effective immune response against Salmonella, was not favored with L38 or L36 strains. However, increased expression of IL-10 in different portions of the gastrointestinal tract of L38-fed animals is indicative of anti-inflammatory effect to be explored furthermore.

The Science behind the Probiotic Strain Bifidobacterium animalis subsp. lactis BB-12(®)

This review presents selected data on the probiotic strain Bifidobacterium animalis subsp. lactis BB-12^® (BB-12^®), which is the world’s most documented probiotic Bifidobacterium. It is described in more than 300 scientific publications out of which more than 130 are publications of human clinical studies. The complete genome sequence of BB-12^® has been determined and published. BB-12^® originates from Chr. Hansen’s collection of dairy cultures and has high stability in foods and as freeze dried powders. Strain characteristics and mechanisms of BB-12^® have been established through extensive in vitro testing. BB-12^® exhibits excellent gastric acid and bile tolerance; it contains bile salt hydrolase, and has strong mucus adherence properties, all valuable probiotic characteristics. Pathogen inhibition, barrier function enhancement, and immune interactions are mechanisms that all have been demonstrated for BB-12^®. BB-12^® has proven its beneficial health effect in numerous clinical studies within gastrointestinal health and immune function. Clinical studies have demonstrated survival of BB-12^® through the gastrointestinal tract and BB-12^® has been shown to support a healthy gastrointestinal microbiota. Furthermore, BB-12^® has been shown to improve bowel function, to have a protective effect against diarrhea, and to reduce side effects of antibiotic treatment, such as antibiotic-associated diarrhea. In terms of immune function, clinical studies have shown that BB-12^® increases the body’s resistance to common respiratory infections as well as reduces the incidence of acute respiratory tract infections.