Adhesion of inactivated probiotic strains to intestinal mucus

Protective Effects of the Postbiotic Lactobacillus plantarum MD35 on Bone Loss in an Ovariectomized Mice Model

Postmenopausal osteoporosis is caused by estrogen deficiency, which impairs bone homeostasis, resulting in increased osteoclastic resorption without a corresponding increase in osteoblastic activity. Postbiotics have several therapeutic properties, including anti-obesity, anti-diabetic, anti-inflammatory, and anti-osteoporotic effects. However, the beneficial effects of the postbiotic MD35 of Lactobacillus plantarum on bone have not been studied. In this study, we demonstrated that the postbiotic L. plantarum MD35, isolated from young radish water kimchi, influences osteoclast differentiation in mouse bone marrow-derived macrophage (BMM) culture. In addition, it was effective protecting against estrogen deficiency-induced bone loss in ovariectomized (OVX) mice, an animal model of postmenopausal osteoporosis. In BMM cells, postbiotic MD35 inhibited the receptor activator of nuclear factor-kappa B of NF-κB ligand (RANKL)-induced osteoclast differentiation by attenuating the phosphorylation of extracellular signal-related kinase, significantly suppressing the resorption activity and down-regulating the expression of RANKL-mediated osteoclast-related genes. In the animal model, the oral administration of postbiotic MD35 remarkably improved OVX-induced trabecular bone loss and alleviated the destruction of femoral plate growth. Therefore, postbiotic MD35 could be a potential therapeutic candidate for postmenopausal osteoporosis by suppressing osteoclastogenesis through the regulation of osteoclast-related molecular mechanisms.

Probiotics and Paraprobiotics: Effects on Microbiota-Gut-Brain Axis and Their Consequent Potential in Neuropsychiatric Therapy

Neuropsychiatric disorders are clinical conditions that affect cognitive function and emotional stability, often resulting from damage or disease in the central nervous system (CNS). These disorders are a worldwide concern, impacting approximately 12.5% of the global population. The gut microbiota has been linked to neurological development and function, implicating its involvement in neuropsychiatric conditions. Due to their interaction with gut microbial communities, probiotics offer a natural alternative to traditional treatments such as therapeutic drugs and interventions for alleviating neuropsychiatric symptoms. Introduced by Metchnikoff in the early 1900s, probiotics are live microorganisms that provide various health benefits, including improved digestion, enhanced sleep quality, and reduced mental problems. However, concerns about their safety, particularly in immunocompromised patients, warrant further investigation; this has led to the concept of "paraprobiotics", inactivated forms of beneficial microorganisms that offer a safer alternative. This review begins by exploring different methods of inactivation, each targeting specific cellular components like DNA or proteins. The choice of inactivation method is crucial, as the health benefits may vary depending on the conditions employed for inactivation. The subsequent sections focus on the potential mechanisms of action and specific applications of probiotics and paraprobiotics in neuropsychiatric therapy. Probiotics and paraprobiotics interact with gut microbes, modulating the gut microbial composition and alleviating gut dysbiosis. The resulting neuropsychiatric benefits primarily stem from the gut-brain axis, a bidirectional communication channel involving various pathways discussed in the review. While further research is needed, probiotics and paraprobiotics are promising therapeutic agents for the management of neuropsychiatric disorders.

Role of Probiotics in Human Health

Certain bacteria, known as probiotics, have had a vastly beneficial effect on people's health; considering their benefits they have been mixed with a wide variety of foods for several decades now. The ability of probiotics to modify the immunological response of the host, antagonize pathogenic microbes, or compete for adhesion sites with pathogenic microorganisms is related to the action of probiotics against microorganisms. Infections of the digestive tract, irritable bowel, lactose intolerance, allergies, infections of the urogenital tract, cystic fibrosis, and various cancers can all be prevented and treated with the use of probiotics. They can reduce the side effects of various antibodies. In the field of oral health, dental caries, periodontal disease, and bad breath can be prevented and treated with the use of probiotics. The findings of several of these clinical studies indicate that probiotics may be beneficial in the treatment and prevention of various diseases and health issues. Validation of a significant number of these clinical investigations is necessary before the results can be applied to the clinical setting. Clinical studies play an important part in such investigations, and in the not-too-distant future, the outcomes of such trials will determine whether or not probiotics are effective in the treatment of disease. This article will attempt to provide a summary of the available literature on the benefits that these probiotics have with regard to health and disease. Probiotics are foods and/or supplements that contain non-pathogenic microbes such as bacteria and yeast that colonize the gut and can potentially yield a variety of health benefits. Research into the various ways in which probiotic bacteria could be used in the treatment of intestinal disorders is ongoing. Thanks to clinical studies and laboratory experiments, we now know more about how probiotics affect gut microbiome disorders. Studies can prove that probiotics can alleviate a variety of gastrointestinal ailments and improve overall health. This article concentrates on probiotics and commensal microbes, as well as their potential role in gut microbiome-related illnesses. In this section, we mark certain areas that need further work and studies so as to enhance our understanding of how probiotics help in the treatment and reduction of chances of gastrointestinal diseases.

The clinical evidence for postbiotics as microbial therapeutics

An optimally operating microbiome supports protective, metabolic, and immune functions, but disruptions produce metabolites and toxins which can be involved in many conditions. Probiotics have the potential to manage these. However, their use in vulnerable people is linked to possible safety concerns and maintaining their viability is difficult. Interest in postbiotics is therefore increasing. Postbiotics contain inactivated microbial cells or cell components, thus are more stable and exert similar health benefits to probiotics. To review the evidence for the clinical benefits of postbiotics in highly prevalent conditions and consider future potential areas of benefit. There is growing evidence revealing the diverse clinical benefits of postbiotics in many prevalent conditions. Postbiotics could offer a novel therapeutic approach and may be a safer alternative to probiotics. Establishing interaction mechanisms between postbiotics and commensal microorganisms will improve the understanding of potential clinical benefits and may lead to targeted postbiotic therapy.

Irradiated Non-replicative Lactic Acid Bacteria Preserve Metabolic Activity While Exhibiting Diverse Immune Modulation

In the recent years, safety concerns regarding the administration of probiotics led to an increased interest in developing inactivated probiotics, also called “paraprobiotics”. Gamma irradiation represents a promising tool that can be used to produce safe paraprobiotics by inhibiting replication while preserving the structure, the metabolic activity, and the immunogenicity of bacteria. In this study, we evaluated the ability of four strains of lactic acid bacteria (LAB: Lacticaseibacillus casei, Lactobacillus acidophilus, Lactiplantibacillus plantarum, and Lacticaseibacillus paracasei) in preserving the metabolic activity and the immune modulation of swine porcine peripheral blood mononuclear cells, after gamma irradiation or heat inactivation. Our results show that all four strains retained the metabolic activity following gamma irradiation but not after heat inactivation. In terms of immune-modulatory capacity, irradiated L. acidophilus and Lc. paracasei were able to maintain an overall gene expression pattern similar to their live state, as heat inactivation did with Lc. casei. Moreover, we show that the two inactivation methods applied to the same strain can induce an opposed expression of key genes involved in pro-inflammatory response (e.g., IFNα and interleukin-6 for Lc. casei), whereas gamma irradiation of L. acidophilus and Lc. paracasei was able to induce a downregulation of the anti-inflammatory TGFβ. Taken together, our data show that immune modulation can be impacted not only by different inactivation methods but also by the strain of LAB selected. This study highlights that gamma irradiation harbors the potential to produce safe non-replicative metabolically active LAB and identifies immunomodulatory capacities that may be applied as vaccine adjuvants.

Immunomodulatory Effect of Bifidobacterium, Lactobacillus, and Streptococcus Strains of Paraprobiotics in Lipopolysaccharide-Stimulated Inflammatory Responses in RAW-264.7 Macrophages

The discovery of the potential of paraprobiotics to exert different immunological benefits suggests that further studies should be carried out to determine their potential and mechanisms of action in modulating the immune system. The objective of this study was to investigate the immune response of several microbial-associated molecular patterns (MAMPS) used at different doses in macrophage cell lines RAW-264.7 stimulated with lipopolysaccharide (LPS). Two experiments were conducted. The first was performed to determine a dose response curve for each paraprobiotic (Bifidobacterium lactis, Lactobacillus casei, Lactobacillus gasseri, Lactobacillus paracasei, and Streptococcus thermophilus). Further experiments were carried using only two doses (0.01 g/ml and 0.1 g/ml). RAW-264.7 cells were cultivated in Dubelcco's Modified Eagle's medium supplemented with fetal bovine serum and penicillin/streptomycin. Cells were incubated with LPS (1 μg/ml) and six concentrations of MAMPs were added. RAW-264.7 viability, myeloperoxidase activity, nitrite/nitrate concentration, reactive oxygen species production, oxidative damage, and inflammatory parameters were measured. In the LPS group, there was a significant reduction in cell viability. Myeloperoxidase and nitrite/nitrate concentrations demonstrated a better effect at 0.01 and 0.1 g/ml doses. There was a significant reduction in interleukin-6 (IL-6) levels at 0.1 g/ml dose in all paraprobiotics. IL-10 levels decreased in the LPS group and increased at 0.1 g/ml dose in all paraprobiotics. The dichlorofluorescin diacetate results were reinforced by the observed in oxidative damage. Paraprobiotics are likely to contribute to the improvement of intestinal homeostasis, immunomodulation, and host metabolism.

Azolla leaf meal at 5% of the diet improves growth performance, intestinal morphology and p70S6K1 activation, and affects cecal microbiota in broiler chicken

With growing concern about including unconventional dietary protein sources in poultry diets to substitute the protein sources that are essential for human consumption such as soybean meal, Azolla leaf meal (ALM) has grown in popularity. In our prior experiment, ALM was used at inclusion rates of 5 and 10%. Five per cent inclusion of ALM increased broiler chicken growth performance, the concentration of cecal propionic acid, and activation of skeletal muscle p70S6 Kinase1 (p70S6K1) without having detrimental effects on the meat quality. Those results prompted us to further evaluate the effect of the same inclusion rates of ALM on phase feeding and intestine and liver health of the broiler chicks. The current study hypothesis is that dietary ALM positively affects phase feeding, intestinal morphology and p70S6K1 activation, cecal microbial gene expression, and improves the liver energy status. For this, we enrolled 135 one-day-old broiler chicks and collected growth performance data (starter, grower, and finisher stages) and samples of the gastrointestinal tract to analyse the morphology of the villi, immune-related organs, mucin, and abundance of intestinal p70S6K1. Cecal bacterial species were analysed using qPCR and liver samples were collected to analyse adenosine monophosphate (AMP) and ATP content and selected oxidative stress biomarkers. ALM increased BW and feed intake during the starter and grower phases but did not affect the feed conversion ratio. Liver oxidative stress and AMP: ATP ratio increased in chickens fed on a diet containing 10% ALM (AZ10; P < 0.05). Jejunum villi length and abundance of duodenal neutral mucin increased but villi of the ileum decreased in chickens fed on a diet containing 5% ALM (AZ5), while lymphoid follicle areas of the cecal tonsils decreased with both doses of ALM. Activation of p70S6K1 increased with AZ10 in the duodenum and AZ5 in the jejunum. In the gut, the family of Enterobacteriaceae decreased with both ALM doses. In conclusion, our results indicate an overall positive effect of dietary inclusion of ALM in the broiler chicken diet via its positive effect on intestinal morphology and function; however, a negative effect on the liver was observed with 10% ALM.

The in vitro antiviral activity of Lacticaseibacillus casei MCJ protein-based metabolites on bovine viral diarrhea virus

Bovine viral diarrhea virus (BVDV) is a ubiquitous immunosuppressive etiological agent which is economically important for a wide host range in the livestock industry. Lactobacillus spp. has widely been using in the field of management and treatment of gastro-enteric disease for both humans and animals. The ability of Lacticaseibacillus casei MCJ protein-based metabolized to suppress BVDV infection in Madin-Darby Bovine Kidney cell line was demonstrated in this study. The protein-based metabolites were extracted from the cultured L. casei to obtain the safest and beneficial form of the probiotic bacteria. It is revealed that LPM have no cytotoxic effect and the cell viability remain more than 80% even after the cells are treated with 3000 µg/mL of LPM. The results of the plaque formation assay showed that LPM can reduce the viral infection rate. To know the mechanism of LPM for anti-BVDV activity, MDBK cells were exposed to LPM before, after and co-incubation of virus infection. The co-treatment of LPM with BVDV revealed the best results. The results suggest that the LPM has a potential anti-BVDV activity which could be a prospective candidate for the prevention and control of BVDV infection in an animal.

The Effects of Supplementation with Probiotic on Biomarkers of Oxidative Stress in Adult Subjects: a Systematic Review and Meta-analysis of Randomized Trials

Previous studies have supposed that probiotic supplementation led to a positive effect on different health outcomes. Furthermore, several studies indicated that probiotics supplementation improved antioxidant status, while some studies did not indicate these effects. Hence, current systematic review and meta-analysis study was conducted to determine the effect of probiotic supplementation on some oxidative stress biomarkers among adult subjects. We searched four electronic databases PubMed, SCOPUS, ISI Web of Science, and the Cochrane Library till November 2017. Clinical trials that compared the effects of probiotic supplementation with the control group were included. A random-effect model was used to pool weighted mean difference (WMD). Finding of 11 included studies (n = 577) indicated that probiotic supplementation increased total antioxidant capacity (TAC) (WMD 77.30 mmol/L; 95% confidence interval [CI] 2.60, 152.01; I² = 88.3%) and reduced malondialdehyde (MDA) (WMD - 0.31 μmol/L; 95% CI - 0.54, - 0.08; I² = 71.5%) significantly compared to the control group. However, its effects on glutathione (GSH) was not significant (WMD = 19.32 μmol/L; 95% CI - 18.70, 57.33; I² = 64.9%). The current meta-analysis revealed that probiotic supplementation may result in increasing TAC and lowering MDA, which improve antioxidant status. However, due to high heterogeneity, findings should be interpreted with caution. Further investigations are required to elucidate the effect of supplementation with probiotics on biomarkers of antioxidants.

Exploring the bone sparing effects of postbiotics in the post-menopausal rat model

Background

Post-menopausal osteoporosis is a concern of health organizations, and current treatments do not seem enough. Postbiotics as bioactive compounds produced by probiotics may be an attractive alternative for bone health. In this study, we prepared, formulated, and compared the effects of cell lysate and supernatant of five native probiotic strains (Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus casei, Bifidobacterium longum, and Bacillus coagulans) in ovariectomized (OVX) rats.

Methods

The probiotic strains were isolated, and their cell-free supernatants and biomasses as postbiotics were extracted and formulated using standard microbial processes. The Sprague-Dawley rats were fed by 1 × 10⁹ CFU/ml/day postbiotic preparations for 4 weeks immediately after ovariectomy. Dual-energy X-ray absorptiometry (DEXA) scans were accomplished to evaluate femur, spine, and tibia BMD. The serum biochemical markers [calcium, phosphorus, and alkaline phosphatase] were assessed.

Results

Postbiotics could considerably improve the global and femur area in OVX rats. In the case of global bone mineral density (BMD), Lactobacillus casei lysate and supernatant, Bacillus coagulans lysate and supernatant, lysate of Bifidobacterium longum and Lactobacillus acidophilus, and Lactobacillus reuteri supernatant significantly increased BMD. We found Bacillus coagulans supernatant meaningfully enriched tibia BMD.

Conclusion

Postbiotic could ameliorate bone loss resulting from estrogen deficiency. Also, the effects of postbiotics on different bone sites are strain-dependent. More clinical studies need to explore the optimal administrative dose and duration of the specific postbiotics in protecting bone loss.

Cell surface and extracellular proteins of potentially probiotic Lactobacillus reuteri as an effective mediator to regulate intestinal epithelial barrier function

The present study aimed to evaluate the potential of cell surface and extracellular proteins in regulation of intestinal epithelial barrier (IEB) function. Eight potentially probiotic L. reuteri strains were evaluated for presence of mapA gene and its expression on co-culturing with the Caco-2 cells. The ability of untreated (Viable), heat-inactivated, 5 M LiCL treated L. reuteri strains as well as their cell-free supernatant (CFS) to modulate expression of IEB function genes (hBD-2, hBD-3, claudin-1 and occludin) was also evaluated. Caco-2 cells were treated with cell surface and extracellular protein extracts and investigated for change in expression of targeted IEB function genes. The results showed that mapA gene is present in all the tested L. reuteri strains and expression of mapA and its receptors (anxA13 and palm) increase significantly on co-culturing of L. reuteri and Caco-2 cells. Also, up-regulated expression of IEB function genes was observed on co-culturing of L. reuteri (viable, heat-inactivated and CFS) and their protein extracts with Caco-2 cells in contrast to down-regulation observed with the pathogenic strain of Salmonella typhi. Therefore, this study concludes that the cell surface and extracellular protein from L. reuteri act as an effective mediator molecules to regulate IEB function.

In Vitro and In Vivo Evaluation of the Probiotic Potential of Antarctic Yeasts

Antarctica is one of the most pristine and inhospitable regions of the planet, mostly inhabited by microorganisms that survive due to unusual metabolic pathways to adapt to its extreme conditions, which could be interesting for the selection of new probiotics. The aim of the present study was to screen in vitro and in vivo putative probiotics among 254 yeasts isolated from different habitats of Antarctica. In vitro selection evaluated functional (growth at 37 °C, resistance to simulated gastric environment, and to bile salts), safety (degradation of mucin, production of β-haemolysis and resistance to antifungal drugs), and beneficial (production of antagonistic substances and adhesion to pathogens) properties. Twelve yeasts were able to grow at 37 °C, one of which was eliminated to present β-haemolytic ability. The remained yeasts resisted to gastric simulation and bile salts, but none presented antagonism against the pathogens tested. Because of the high co-aggregation with Salmonella enterica Typhimurium and growth yield, Rhodotorula mucilaginosa UFMGCB 18377 and Saccharomyces cerevisiae UFMGCB 11120 were selected for in vivo steps using mice challenged with S. Typhimurium. Both yeasts reached high faecal population levels when daily administered, but only R. mucilaginosa UFMGCB 18377 protected mice against Salmonella infection presenting a higher survival and reduced weight loss, bacterial translocation to the liver, sIgA intestinal levels, and intestinal and hepatic MPO and EPO activities. Our in vitro and in vivo results suggest that R. mucilaginosa UFMGCB 18377 presents probiotic potential and deserve further studies as candidate of probiotic by-products. In addition, this is the first screening study of yeasts isolated from Antarctic environments and of Rhodotorula genus for probiotic use.

Interleukin-8 gene expression and apoptosis induced by Salmonella Typhimurium in the presence of Bacillus probiotics in the epithelial cell

AIMS

This study aimed to evaluate the effects of three Bacillus probiotics on Salmonella Typhimurium, and interleukin-8 (IL-8) gene expression in the co-culture of the Bacillus and the pathogen in vitro.

METHODS AND RESULTS

Bacillus subtilis, Bacillus indicus and Bacillus coagulans were initially turned to spore and heat-inactivated forms. The cellular damages of the probiotics on the HT-29 cells were investigated individually and in combination with S. Typhimurium using 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and fluorescence assays. To extract cell free supernatants (CFS) of the probiotics, they were cultured in selective media. The inhibitory activity of CFSs were then assayed against the pathogen. The gene expression of IL-8 of the HT-29 cells was evaluated by real-time PCR in all the groups. The results showed that the CFSs of three probiotics could inhibit the growth of S. Typhimurium by more than 50%. Inhibitory effects of B. indicus and B. subtilis CFSs were related to the production of pepsin-sensitive compounds, except B. coagulans in which the high inhibitory effect was due to organic acids. The spores of the three probiotics and the heat-inactivated forms of B. subtilis and B. coagulans could reduce the cytotoxicity of S. Typhimurium. The cell viability also increased applying both forms probiotics against the pathogen. In all co-culture groups, the IL-8 gene expression induced by S. Typhimurium was reduced.

CONCLUSIONS

The three Bacillus probiotics can be considered as proper candidates for the prevention and treatment of S. Typhimurium food poisoning.

SIGNIFICANCE AND IMPACT OF THE STUDY

Applying probiotics as live bacteria is universally noted in foods. This study tried to discover the effects of Bacillus probiotics in the form of spore or even heat-killed bacteria against S. Typhimurium and evaluate ratio of IL-8 gene expression in cell culture. The most effective Bacillus probiotic will be recommended. This approach will help to use probiotics as nonvegetative cells in foods to fight gastrointestinal pathogens.

Cytotoxicity, apoptosis, and IL-8 gene expression induced by some foodborne pathogens in presence of Bacillus coagulans in HT-29 cells

Food poisoning caused by bacteria is one of the most important concerns in food hygiene. The use of probiotics in prevention, control, and treatment of these infections has been considerably increased in recent years. This study evaluated the effect of B. coagulans cell free supernatant (CFS) on growth of Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, non-pathogenic Escherichia coli, and Escherichia coli 0157:H7 by the broth dilution method. The cytotoxicity, and apoptosis induced by pathogens alone and in co-culture with B. coagulans or its CFS were measured by trypan blue, and fluorescence staining methods. The expression level of interleukin-8 (IL-8) cytokine-encoding genes was also investigated by a qRT-PCR assay in all pathogens and co-cultured groups in HT-29 cells. Our results showed that 4% B. coagulans CFS reduced pathogen growth. The highest rate of growth inhibition was observed in L. monocytogenes. We also found that B. coagulans, and its 4% CFS reduced the cytotoxic effects of pathogens, with the exception of S. aureus. Non-pathogenic E. coli also had no significant cytotoxic effect on the cells. Examination of the treated cells with acridine orange/ethidium bromide staining showed reductions in the rate of cell damage (including early apoptosis, late apoptosis, and necrosis) in pathogen-probiotic co-cultures. Furthermore, we showed that co-culture of pathogens with B. coagulans significantly down-regulated IL-8 gene expression (P < 0.05). The greatest down-regulation compared with pathogen alone was observed in S. aureus. Hence, B. coagulans can be considered as an appropriate probiotic to diminish cytotoxicity, and inflammatory response of enteropathogenic bacteria.

The effects of probiotic/synbiotic supplementation compared to placebo on biomarkers of oxidative stress in adults: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

During the last decades, there has been a burst of scientific literature hypothesizing the antioxidant effect of probiotics. However, the results of these studies are inconsistent and a final conclusion has yet to be reached. Thus, the aim of this study was to assess the effects of probiotic/synbiotic supplementation on serum total antioxidant capacity (TAC), glutathione (GSH), malondialdehyde (MDA) and nitric oxide (NO) levels in adults.

METHODS AND RESULTS

The following online databases were searched until August 26th 2020: PubMed/Medline, Scopus, Clarivate Analytics Web of Science, Cochrane Central Register of Controlled Trials, Science Direct, Google Scholar and Igaku Chuo Zasshi. The effect sizes were expressed as the weighted mean difference (WMD) with 95% confidence intervals (CI). A total of 31 eligible trials with 1681 participants (839 cases and 842 controls) were included in this meta-analysis. The results revealed that the supplementation with probiotics/synbiotics, significantly increased serum TAC (WMD: 54.14 mmol/L, 95% CI: 27.87, 80.40, P < 0.001), GSH (WMD: 40.38 μmol/L, 95% CI: 20.72, 60.03, P < 0.001) and NO (WMD: 3.54 μmol/L, 95% CI: 1.73, 5.34, P < 0.001) levels. In addition, MDA levels were significantly reduced (WMD: -0.45 μmol/L, 95% CI: -0.58,-0.32, P < 0.001) following probiotic/synbiotic supplementation. None of the variables showed a significant change in the sensitivity analysis.

CONCLUSION

Available evidence suggests that probiotic/synbiotic supplementation can significantly increase serum TAC, GSH and NO, as well as reduce MDA levels in adults. Therefore, probiotic/synbiotic supplementation may play a role in improving antioxidant indices and reducing oxidative stress in the body.

Postbiotics against Pathogens Commonly Involved in Pediatric Infectious Diseases

The Sustainable Development goals for 2020 included reducing all causes associated with infant and perinatal mortality in their priorities. The use of compounds with bioactive properties has been proposed as a therapeutic strategy due to their stimulating effect on the host's immune system. Additionally, biotherapeutic products such as postbiotics, tentatively defined as compounds produced during a fermentation process that support health and well-being, promote intestinal barrier integrity without posing considerable risks to children's health. Although this is a concept in development, there are increasing studies in the field of nutrition, chemistry, and health that aim to understand how postbiotics can help prevent different types of infections in priority populations such as minors under the age of five. The present review aims to describe the main mechanisms of action of postbiotics. In addition, it presents the available current evidence regarding the effects of postbiotics against pathogens commonly involved in pediatric infections. Postbiotics may constitute a safe alternative capable of modulating the cellular response and stimulating the host's humoral response.

Paraprobiotics and postbiotics: Contemporary and promising natural antibiotics alternatives and their applications in the poultry field

With the high rise of drug resistance in microbial populations, there has been a surge in researches to find new natural antibiotics alternative compounds that can be used safely in both humans and animals. The main goals of using this category of alternatives are maintaining the gut microbiome in healthy conditions and preventing the attachment of pathogenic organisms at the early life stages. Probiotics, prebiotics, and synbiotics have been widely used for several years as growth promoters and as preventive measures against several enteric pathogens with successful results. Recently, paraprobiotics and postbiotics are derivatives of probiotic cultures and have been used in humans, animals, and poultry. They are regarded as immunostimulators, anti-inflammatory, antioxidants, and anti-microbial, as well as growth promoters. Till now, there is scanty information about the use of paraprobiotics and postbiotics in animals or in the poultry sector. Accordingly, this review article has focused on defining these new categories of natural alternatives with descriptions of their types, functions, and uses, especially in the poultry field.

Isolation, identification and characterization of Staphylococcus sp. from Indian ethnic fermented fish product

Staphylococci from Sheedal of Northeast India was isolated, identified and characterized. All the isolated staphylococci were found to be coagulase negative. Based on the rpoB gene sequences followed by analysis using NCBI-BLAST software, seven species of Staphylococcus namely, S. piscifermentans, S. condimenti, S. arlettae, S. sciuri, S. warneri, S. nepalensis and S. hominis were recognized. Phylogenetic analyses revealed three major cluster groups. All the seven Staphylococcus showed their NaCl tolerance from 2 to 8%. No species was able to grow at 55°C. Except S. arlettae and S. sciuri, all the isolated staphylococcal species exhibited growth at pH 4-8. No isolated species was able to ferment mannitol, sucrose and arabinose. All the species exhibited moderate to maximum proteolytic and lipolytic activities. All the seven species were found to be sensitive to the antibiotics, namely, erythromycin, norfloxacin, ampicillin, streptomycin and vancomycin, whereas all were resistant to co-trimoxazole. Only S. piscifermentans was found antagonist to Salmonella enterica, Escherichia coli and Bacillus subtilis, although the clear zone was minimal. All the staphylococcal species except S. arlettae and S. sciuri exhibited hydrophobicity ranging from 25 to 66%. The observed characteristics of isolated Staphylococci from Sheedal revealed their role in fish fermentation.

In Vitro Effects of Live and Heat-Inactivated Bifidobacterium animalis Subsp. Lactis, BB-12 and Lactobacillus rhamnosus GG on Caco-2 Cells

Probiotic–host interaction can be cell-to-cell or through metabolite production. Dead (inactive) organisms could interact with the host, leading to local effects and possible health benefits. This research examined the effects of live and heat-inactivated Bifidobacterium animalis subsp. lactis, BB-12 (BB-12) and Lactobacillus rhamnosus GG (LGG) on cultured Caco-2 cells focusing on epithelial integrity and production of inflammatory mediators. Live organisms increased transepithelial electrical resistance (TEER), a barrier-integrity marker, with LGG having a greater effect than BB-12. When mildly heat-treated, both organisms had a more modest effect on TEER than when alive. When they were heat-inactivated, both organisms had only a limited effect on TEER. Neither live nor heat-inactivated organisms affected production of six inflammatory mediators produced by Caco-2 cells compared to control conditions. Pre-treatment with heat-inactivated LGG or BB-12 did not alter the decline in TEER caused by exposure to an inflammatory cocktail of cytokines. However, pre-treatment of Caco-2 cells with heat-inactivated organisms alone or their combination decreased the production of interleukin (IL)-6, IL-18, and vascular endothelial growth factor. To conclude, while the live organisms improve the epithelial barrier using this model, neither live nor heat-inactivated organisms directly elicit an inflammatory response by the epithelium. Pre-treatment with heat-inactivated BB-12 or LGG can reduce some components of the response induced by an inflammatory stimulus.

Postbiotics for Preventing and Treating Common Infectious Diseases in Children: A Systematic Review

Postbiotics have recently been tentatively defined as bioactive compounds produced during a fermentation process (including microbial cells, cell constituents and metabolites) that supports health and/or wellbeing. Postbiotics are currently available in some infant formulas and fermented foods. We systematically reviewed evidence on postbiotics for preventing and treating common infectious diseases among children younger than 5 years. The PubMed, Embase, SpringerLink, and ScienceDirect databases were searched up to March 2019 for randomized controlled trials (RCTs) comparing postbiotics with placebo or no intervention. Seven RCTs involving 1740 children met the inclusion criteria. For therapeutic trials, supplementation with heat-killed Lactobacillus acidophilus LB reduced the duration of diarrhea (4 RCTs, n = 224, mean difference, MD, -20.31 h, 95% CI -27.06 to -13.57). For preventive trials, the pooled results from two RCTs (n = 537) showed that heat-inactivated L. paracasei CBA L74 versus placebo reduced the risk of diarrhea (relative risk, RR, 0.51, 95% CI 0.37-0.71), pharyngitis (RR 0.31, 95% CI 0.12-0.83) and laryngitis (RR 0.44, 95% CI 0.29-0.67). There is limited evidence to recommend the use of specific postbiotics for treating pediatric diarrhea and preventing common infectious diseases among children. Further studies are necessary to determine the effects of different postbiotics.

Droplet Digital PCR Is an Improved Alternative Method for High-Quality Enumeration of Viable Probiotic Strains

Traditional microbiological enumeration methods have long been employed as the standard evaluation procedure for probiotic microorganisms. These methods are labor intensive, have long-time to results and inherently have a high degree of variability – up to 35%. As clinical probiotic and microbiome science continues to grow and develop, it is increasingly important that researchers thoroughly define and deliver the targeted probiotic dose. Furthermore, to establish high quality commercial products, the same dosage level must be administered to consumers. An ISO method for the use of flow cytometry has been established which does speed up the time to results and reduce variability, but the method has not yet gained widespread adoption across the probiotic industry. This is possibly due to expertise needed to implement and maintain a new testing platform in an established quality system. In this study we compare enumeration using plate counts and flow cytometry to the use of droplet digital PCR (ddPCR), which in addition to giving faster time to results than plate count and less variability than both plate count and flow cytometry, has additional benefits such as strain-specific counts. Use of ddPCR gives the ability to design primers to target deletions and single base pair differences which will allow for strain profiling in microbiome analyses. We demonstrate that ddPCR probiotic enumeration results are positively correlated to both plate count and flow cytometry results and should be considered a viable, next generation enumeration method for the evaluation of probiotics.

Postbiotics and Their Potential Applications in Early Life Nutrition and Beyond

Postbiotics are functional bioactive compounds, generated in a matrix during fermentation, which may be used to promote health. The term postbiotics can be regarded as an umbrella term for all synonyms and related terms of these microbial fermentation components. Therefore, postbiotics can include many different constituents including metabolites, short-chain fatty acids (SCFAs), microbial cell fractions, functional proteins, extracellular polysaccharides (EPS), cell lysates, teichoic acid, peptidoglycan-derived muropeptides and pili-type structures. Postbiotics is also a rather new term in the '-biotics' field. Where consensus exists for the definitions of pre- and probiotics, this is not yet the case for postbiotics. Here we propose a working definition and review currently known postbiotic compounds, their proposed mechanisms, clinical evidence and potential applications. Research to date indicates that postbiotics can have direct immunomodulatory and clinically relevant effects and evidence can be found for the use of postbiotics in healthy individuals to improve overall health and to relief symptoms in a range of diseases such as infant colic and in adults atopic dermatitis and different causes of diarrhea.

Comparative genomics and functional analysis of a highly adhesive dairy Lactobacillus paracasei subsp. paracasei IBB3423 strain

Various Lactobacillus paracasei strains are found in diverse environments, including dairy and plant materials and the intestinal tract of humans and animals, and are also used in the food industry or as probiotics. In this study, we have isolated a new strain L. paracasei subsp. paracasei IBB3423 from samples of raw cow milk collected in a citizen science project. IBB3423 showed some desired probiotic features such as high adhesion capacity and ability to metabolize inulin. Its complete genome sequence comprising the chromosome of 3,183,386 bp and two plasmids of 5986 bp and 51,211 bp was determined. In silico analysis revealed numerous genes encoding proteins involved in carbohydrate metabolism and of extracellular localization likely supporting interaction with host tissues. In vitro tests confirmed the high adhesion capacity of IBB3423 and showed that it even exceeds that of the highly adhesive L. rhamnosus GG. Curing of the larger plasmid indicated that the adhesive properties depend on the plasmid and thus could be determined by its pilus-encoding spaCBA genes.

MMP7 Modulation by Short- and Long-term Radiotherapy in Patients with Rectal Cancer

BACKGROUND/AIM

Matrix metalloproteinase 7 (MMP7) expression is highly associated with colorectal cancer and modulates tumour growth and invasion. Radiation injury induces inflammation with increases in MMP7 and in transforming growth factor beta (TGFβ). The aim of this study was to investigate the effect on MMP7 and TGFβ. expression in patients with rectal cancer undergoing different regimens of neoadjuvant radiotherapy (RT).

PATIENTS AND METHODS

We studied 53 patients in three RT treatment groups receiving RT of 25 Gy, long-term RT 50 Gy and controls receiving no RT. Three biopsies were obtained from each patient during the treatments: before RT, after RT and after surgery. Tissue samples were formalin fixed, paraffin embedded and tissue microarrays were constructed and stained for MMP7 and TGFβ. Mann-Whitney U-tests and Wilcoxon Z-tests were used to determine differences between patients before and after RT, and after surgery, as well as between the RT groups.

RESULTS

In all three patient groups, increases of MMP7 and TGFβ expression were observed after surgery. MMP7 expression was significantly increased in patients receiving short-term RT but TGFβ expression was not affected by RT.

CONCLUSION

50 Gy Irradiation of rectal cancer gives less tumour activation of MMP7, whilst it is up-regulated by 25 Gy and surgery regardless of RT.

Para-probiotics for Preterm Neonates-The Next Frontier

Current evidence supports the use of probiotics in preterm neonates for prevention of necrotizing enterocolitis, mortality and late onset sepsis. Despite the strong evidence, the uptake of this intervention has not been universal due to concerns including probiotic sepsis, pro-inflammatory response and transmission of antibiotic resistance. Critically ill extremely preterm neonates with potentially compromised gut integrity are at higher risk of probiotic sepsis due to translocation. In most countries, probiotics are sold as food supplements with poor quality control. The traditional definition of probiotics as &ldquo;live microorganisms&rdquo; has been challenged as many experts have questioned the importance of viability in the context of the beneficial effects of probiotics. Paraprobiotics (ghost probiotics), are defined as non-viable microbial cells (intact or broken) or crude cell extracts (i.e., with complex chemical composition), which, when administered (orally or topically) in adequate amounts, confer a benefit on the human or animal consumer. Current evidence indicates that paraprobiotics could be safe alternatives to probiotics in preterm neonates. High-quality pre-clinical and clinical studies including adequately powered randomised controlled trials (RCTs) are warranted in preterm neonates to explore this new frontier.

Propionibacterium freudenreichii Surface Protein SlpB Is Involved in Adhesion to Intestinal HT-29 Cells

Propionibacterium freudenreichii is a beneficial bacterium traditionally used as a cheese ripening starter and more recently for its probiotic abilities based on the release of beneficial metabolites. In addition to these metabolites (short-chain fatty acids, vitamins, and bifidogenic factor), P. freudenreichii revealed an immunomodulatory effect confirmed in vivo by the ability to protect mice from induced acute colitis. This effect is, however, highly strain-dependent. Local action of metabolites and of immunomodulatory molecules is favored by the ability of probiotics to adhere to the host cells. This property depends on key surface compounds, still poorly characterized in propionibacteria. In the present study, we showed different adhesion rates to cultured human intestinal cells, among strains of P. freudenreichii. The most adhesive one was P. freudenreichii CIRM-BIA 129, which is known to expose surface-layer proteins. We evidenced here the involvement of these proteins in adhesion to cultured human colon cells. We then aimed at deciphering the mechanisms involved in adhesion. Adhesion was inhibited by antibodies raised against SlpB, one of the surface-layer proteins in P. freudenreichii CIRM-BIA 129. Inactivation of the corresponding gene suppressed adhesion, further evidencing the key role of slpB product in cell adhesion. This work confirms the various functions fulfilled by surface-layer proteins, including probiotic/host interactions. It opens new perspectives for the understanding of probiotic determinants in propionibacteria, and for the selection of the most efficient strains within the P. freudenreichii species.

Dairy Propionibacteria: Versatile Probiotics

Dairy propionibacteria are used as cheese ripening starters, as biopreservative and as beneficial additives, in the food industry. The main species, Propionibacterium freudenreichii, is known as GRAS (Generally Recognized As Safe, USA, FDA). In addition to another dairy species, Propionibacterium acidipropionici, they are included in QPS (Qualified Presumption of Safety) list. Additional to their well-known technological application, dairy propionibacteria increasingly attract attention for their promising probiotic properties. The purpose of this review is to summarize the probiotic characteristics of dairy propionibacteria reported by the updated literature. Indeed, they meet the selection criteria for probiotic bacteria, such as the ability to endure digestive stressing conditions and to adhere to intestinal epithelial cells. This is a prerequisite to bacterial persistence within the gut. The reported beneficial effects are ranked according to property’s type: microbiota modulation, immunomodulation, and cancer modulation. The proposed molecular mechanisms are discussed. Dairy propionibacteria are described as producers of nutraceuticals and beneficial metabolites that are responsible for their versatile probiotic attributes include short chain fatty acids (SCFAs), conjugated fatty acids, surface proteins, and 1,4-dihydroxy-2-naphtoic acid (DHNA). These metabolites possess beneficial properties and their production depends on the strain and on the growth medium. The choice of the fermented food matrix may thus determine the probiotic properties of the ingested product. This review approaches dairy propionibacteria, with an interest in both technological abilities and probiotic attributes.

Enterococcus durans EP1 a Promising Anti-inflammatory Probiotic Able to Stimulate sIgA and to Increase Faecalibacterium prausnitzii Abundance

Enterococcus species, principally Enterococcus faecium are used as probiotics since a long time with preference in animal applications but safety considerations were updated and also new uses as probiotics can be envisaged. Fifteen Enterococcus strains isolated from different foods were identified and analyzed for virulence factors and antibiotic resistance. Three Enterococcus durans strains were selected to study their immunomodulatory properties on PBMC and Caco2 cells. Two strains presented a profile toward a mild inflammatory Th1 response considering TNF-α/IL-10 and IL-1β/IL-10 cytokines ratios. The third strain EP1, presented an anti-inflammatory potential and was selected for in vivo studies. In mice, the strain was well tolerated and did not cause any adverse effects. EP1 administration increased the amount of IgA+ cells in mesenteric lymph node (MLN) after 7 days of administration. In fecal samples, the IgA content increased gradually and significantly from day 7 to day 21 in treated group. Additionally, IL-17, IL-6, IL-1β, IFN-γ, and CXCL1 gene expression significantly decreased on day 21 in Peyer’s patches and IL-17 decreased in MLN. Mice treated with the probiotic showed significant lower mRNA levels of pro-inflammatory cytokines and mucins in the ileum at day 7 while their expression was normalized at day 21. Colonic expression of il-1β, il6, and mucins remain diminished at day 21. Ileum and colon explants from treated mice stimulated in vitro with LPS showed a significant reduction in IL-6 and an increase in IL-10 secretion suggesting an in vivo protective effect of the probiotic treatment against a proinflammatory stimulus. Interestingly, analysis of feces microbiota demonstrated that EP1 administration increase the amount of Faecalibacterium prausnitzii, a butyrate-producing bacteria, which is known for its anti-inflammatory effects. In conclusion, we demonstrated that EP1 strain is a strong sIgA inducer and possess mucosal anti-inflammatory properties. This strain also modulates gut microbiota increasing Faecalibacterium prausnitzii, a functionally important bacterium. Thus, E. durans EP1 is not only a good candidate to increases F. prausnitzii in some cases of dysbiosis but can also be interesting in gut inflammatory disorders therapy.

Inhibition of enteropathogens adhesion to human enterocyte-like HT-29 cells by a dairy strain of Propionibacterium acidipropionici

Adhesion to the host intestinal mucosa is considered relevant for orally delivered probiotics as it prolongs their persistence in the gut and their health promoting effects. Classical propionibacteria are microorganisms of interest due to their role as dairy starters as well as for their functions as probiotics. Propionibacterium acidipropionici Q4, is a dairy strain isolated from a Swiss-type cheese made in Argentina that displays probiotic potential. In the present work we assessed the ability of this strain to adhere to the human enterocyte-like HT-29 cell line and to counteract the adhesion of two common human enteropathogens, such as Escherichia coli C3 and Salmonella Enteritidis 90/390. The results were compared with those obtained with the well-known probiotic Lactobacillus rhamnosus GG. P. acidipropionici Q4 showed a high adhesion capacity, even higher than the reference strain L. rhamnosus GG (42.3±4.4% and 36.2±2.3%, respectively), whereas adhesion of enteropathogens was significantly lower (25.2±2.2% for E. coli and 21.0±3.4% for S. Enteritidis). Propionibacteria as well as lactobacilli were able to inhibit by exclusion and competition the adherence of E. coli C3 and S. Enteritidis 90/390 whereas only L. rhamnosus GG displaced S. Enteritidis from HT-29 intestinal cells. Inhibition of pathogens by propionibacteria was not exerted by antimicrobials or coaggregation but was mainly due to exclusion by cell surface components, such as proteins and carbohydrates. The relevance of cell surface proteins (CSP) for preventing pathogens infection was confirmed by their concentration dependent effect observed for both pathogens: 100 µg/ml of CSP inhibited E. coli attachment almost as untreated propionibacteria, whereas it partially inhibited the attachment of S. Enteritidis. Results suggest that P. acidipropionici Q4 could be considered for the development of propionibacteria containing functional foods helpful in counteracting enteropathogen infection.

Inactivation of Lactobacillus rhamnosus GG by fixation modifies its probiotic properties

Probiotics are microorganisms that have beneficial effects on the host and are safe for oral intake in a suitable dose. However, there are situations in which the administration of living microorganisms poses a risk for immunocompromised host. The objective of this study was to evaluate the influence of several fixation methods on selected biological properties of Lactobacillus rhamnosus GG that are relevant to its probiotic action. Fixation of the bacterial cells with ethanol, 2-propanol, glutaraldehyde, paraformaldehyde, and heat treatment resulted in a significant decrease of alkaline phosphatase, peroxidase, and β-galactosidase activities. Most of the fixation procedures reduced bacterial cell hydrophobicity and increased adhesion capacity. The fixation procedures resulted in a different perception of the bacterial cells by enterocytes, which was shown as changes in gene expression in enterocytes. The results show that some procedures of inactivation allow a fraction of the enzymatic activity to be maintained. The adhesion properties of the bacterial cells were enhanced, but the response of enterocytes to fixed cells was different than to live bacteria. Inactivation allows maintenance and modification of some of the properties of the bacterial cells.

Effect of sodium acetate on the adhesion to porcine gastric mucin in a Lactococcus lactis strain grown on fructose

The association of lactic acid bacteria with mucosal surfaces plays important roles in the beneficial effects of these bacteria on human health, such as colonization of the gastrointestinal tract for pathogen antagonism. Previously, we found that the adhesion of Lactococcus lactis 7-1 to porcine gastric mucin was higher with fructose than with lactose, galactose or xylose as the carbon source. In this study, we examined the effect of growth conditions on the adhesion of strain 7-1 grown on fructose. Medium components affect the adhesion: the adhesion of strain 7-1 grown with sodium acetate was higher than that without it. The enhancement of adhesion by sodium acetate was not observed under aerobic conditions. Cellular properties grown with or without sodium acetate were characterized: strain 7-1 grown with sodium acetate had similar sugar contents, and different fatty acid composition to those grown without it. Strain 7-1 grown with sodium acetate showed significantly lower cell yield and significantly higher hydrophobicity than those grown without it, which is associated with higher adhesion. Fructose and sodium acetate are frequently used in the food industry; this study may reveal a simple way to enhance the adhesion of lactic acid bacteria by growing them with these substances.

New lactic acid bacterial strains from traditional Mongolian fermented milk products have altered adhesion to porcine gastric mucin depending on the carbon source

Attachment of lactic acid bacteria to the mucosal surface of the gastrointestinal tract is a major property of probiotics. Here, we examined the ability of 21 lactic acid bacterial strains isolated from traditional fermented milk products in Mongolia to adhere to porcine gastric mucin in vitro. Higher attachment was observed with Lactobacillus delbrueckii subsp. bulgaricus strains 6-8 and 8-1 than with Lactobacillus rhamnosus GG (positive control). Lactococcus lactis subsp. cremoris strain 7-1 adhered to mucin as effectively as did strain GG. Heat inactivation decreased the adhesive ability of strains 6-8 and 8-1 but did not affect strain 7-1. The adhesion of strains 6-8, 7-1 and 8-1 was significantly inhibited when the cells were pretreated with periodate and trypsin, indicating that proteinaceous and carbohydrate-like cell surface compounds are involved in the adhesion of these strains. The adhesion of strain 7-1 was affected by the type of carbohydrate present in the growth medium, being higher with fructose than with lactose, galactose or xylose as the carbon source. The sugar content of 7-1 cells grown on various carbohydrates was negatively correlated with its adhesive ability. We provide new probiotic candidate strains and new information regarding carbohydrate preference that influences lactic acid bacterial adhesion to mucin.

Adhesion properties of potentially probiotic Lactobacillus kefiri to gastrointestinal mucus

We investigated the mucus-binding properties of aggregating and non-aggregating potentially probiotic strains of kefir-isolated Lactobacillus kefiri, using different substrates. All the strains were able to adhere to commercial gastric mucin (MUCIN) and extracted mucus from small intestine (SIM) and colon (CM). The extraction of surface proteins from bacteria using LiCl or NaOH significantly reduced the adhesion of three selected strains (CIDCA 8348, CIDCA 83115 and JCM 5818); although a significant proportion (up to 50%) of S-layer proteins were not completely eliminated after treatments. The surface (S-layer) protein extracts from all the strains of Lb. kefiri were capable of binding to MUCIN, SIM or CM, and no differences were observed among them. The addition of their own surface protein extract increased adhesion of CIDCA 8348 and 83115 to MUCIN and SIM, meanwhile no changes in adhesion were observed for JCM 5818. None of the seven sugars tested had the ability to inhibit the adhesion of whole bacteria to the three mucus extracts. Noteworthy, the degree of bacterial adhesion reached in the presence of their own surface protein (S-layer) extract decreased to basal levels in the presence of some sugars, suggesting an interaction between the added sugar and the surface proteins. In conclusion, the ability of these food-isolated bacteria to adhere to gastrointestinal mucus becomes an essential issue regarding the biotechnological potentiality of Lb. kefiri for the food industry.

Fabrication, gastromucoadhesivity, swelling, and degradation of zein-chitosan composite ultrafine fibers

Fabrication, via electrospinning, and characterization of an ultrafine structure architected from a blend of hydrophobic zein and hydrophilic chitosan (CS) were conducted. Poly(ethylene oxide) (PEO) and nonionic surfactant, namely, Tween 40, were employed to improve the electrospinnability of the blend, while ethanol was used as a solvent for zein. The effects of ethanol (EtOH) concentration (85% and 90%) and ratio of zein/PEO/CS (95/2.5/2.5 and 87.5/10/2.5) on the fiber morphology as well as gastromucoadhesivity against porcine stomach mucosa were then investigated; polymer-mucosa adhesion was also investigated via Fourier-transform infrared spectroscopy. Swelling and degradation of the composite ultrafine fibers were investigated under 2 simulated gastric conditions, namely, at pH 2 without pepsin and at pH 1.2 with pepsin. Using 85% EtOH as a solvent for zein resulted in a spider-web-like morphology; the maximum detachment force (MDF), which is an indirect indicator of the gastromucoadhesivity was nevertheless higher. Zein-based ultrafine fibers exhibited higher MDF than the zein-PEO-CS composite; however, the cohesiveness of the composite fibers was higher. FTIR spectroscopic results indicated molecular interactions between the composite fibers and mucin functional groups. Swelling of the composite ultrafine fibers in simulated gastric fluid (SGF) at pH 2 without pepsin was not different from that in SGF at pH 1.2 with pepsin. Nevertheless, degradation of the composite fibers in SGF at pH 2 without pepsin was much less than that in SGF at pH 1.2 with pepsin; only 20% degradation was noted in the former case.

Lactobacillus rhamnosus ingestion promotes innate host defense in an enteric parasitic infection

Enteric parasite infections around the world are a huge economic burden and decrease the quality of life for many people. The use of beneficial bacteria has attracted attention for their potential therapeutic applications in various diseases. However, the effects of beneficial bacteria in enteric parasitic infections remain largely unexplored. We investigated the effects of ingestion of Lactobacillus rhamnosus (JB-1) in a model of enteric nematode (Trichuris muris) infection. C57BL/6 (resistant to infection), AKR (susceptible to infection), interleukin 10 (IL-10) knockout (KO), and mucin Muc2 KO mice were infected with T. muris and treated orally with probiotic JB-1 or medium. The mice were sacrificed on various days postinfection to examine goblet cells, epithelial cell proliferation, cytokines, and worm burdens. Treatment with JB-1 significantly enhanced worm expulsion in resistant C57BL/6 mice, and this was associated with increases in IL-10 levels, goblet cell numbers, and epithelial cell proliferation. Beneficial effects of JB-1 were absent in IL-10 KO and resistant mice treated with γ-irradiated bacteria. Live JB-1 treatment also expedited worm expulsion in Muc2 KO mice and, more importantly, in AKR mice (susceptible to infection). Injection of IL-10 directly into the colonic tissue of uninfected mice induced goblet cell hyperplasia. These findings demonstrate that JB-1 modulates goblet cell biology and promotes parasite expulsion via an IL-10-mediated pathway and provide novel insights into probiotic effects on innate defense in nematode infection.

In vitro characterization of aggregation and adhesion properties of viable and heat-killed forms of two probiotic Lactobacillus strains and interaction with foodborne zoonotic bacteria, especially Campylobacter jejuni

Bacterial aggregation and/or adhesion are key factors for colonization of the digestive ecosystem and the ability of probiotic strains to exclude pathogens. In the present study, two probiotic strains, Lactobacillus rhamnosus CNCM-I-3698 and Lactobacillus farciminis CNCM-I-3699, were evaluated as viable or heat-killed forms and compared with probiotic reference Lactobacillus strains (Lb. rhamnosus GG and Lb. farciminis CIP 103136). The autoaggregation potential of both forms was higher than that of reference strains and twice that of pathogenic strains. The coaggregation potential of these two beneficial micro-organisms was evaluated against several pathogenic agents that threaten the global safety of the feed/food chain: Escherichia coli, Salmonella spp., Campylobacter spp. and Listeria monocytogenes. The strongest coaggregative interactions were demonstrated with Campylobacter spp. by a coaggregation test, confirmed by electron microscopic examination for the two forms. Viable forms were investigated for the nature of the bacterial cell-surface molecules involved, by sugar reversal tests and chemical and enzymic pretreatments. The results suggest that the coaggregation between both probiotic strains and C. jejuni CIP 70.2(T) is mediated by a carbohydrate-lectin interaction. The autoaggregation potential of the two probiotics decreased upon exposure to proteinase, SDS or LiCl, showing that proteinaceous components on the surface of the two lactobacilli play an important role in this interaction. Adhesion abilities of both Lactobacillus strains were also demonstrated at significant levels on Caco-2 cells, mucin and extracellular matrix material. Both viable and heat-killed forms of the two probiotic lactobacilli inhibited the attachment of C. jejuni CIP 70.2(T) to mucin. In conclusion, in vitro assays showed that Lb. rhamnosus CNCM-I-3698 and Lb. farciminis CNCM-I-3699, as viable or heat-killed forms, are adherent to different intestinal matrix models and are highly aggregative in vitro with pathogens, especially Campylobacter spp., the most commonly reported zoonotic agent in the European Union. This study supports the need for further in vivo investigations to demonstrate the potential food safety benefits of Lb. rhamnosus CNCM-I-3698 and Lb. farciminis CNCM-I-3699, live or heat-killed, in the global feed/food chain.

Effects of the viability of Lactobacillus rhamnosus GG on rotavirus infection in neonatal rats

AIM: To study the effects of live and dead Lactobacillus rhamnosus GG (GG) on rotavirus infection in a neonatal rat model.

METHODS: At the age of 2 d, suckling Lewis rat pups were supplemented with either live or dead GG and the treatment was continued daily throughout the experiment. At the age of 5 and 6 d the pups received oral rotavirus (RV) SA-11 strain. The pups were sacrificed at the age of 7 or 8 d by decapitation. The gastrointestinal tract was removed and macroscopic observations were done. The consistency of feces in the colon was classified using a four-tier system. RV was detected from the plasma, small intestine, colon and feces by real-time quantitative polymerase chain reaction (PCR).

RESULTS: In this neonatal rat model, RV induced a mild-to-moderate diarrhea in all except one pup of the RV-inoculated rats. RV moderately reduced body weight development from day 6 onwards. On day 7, after 2 d of RV infection, live and dead GG groups gained significantly more weight than the RV group without probiotics [36% (P = 0.001) and 28% (P = 0.031), respectively]. In addition, when compared with the RV control group, both live and dead GG reduced the weight ratio of colon/animal body weight to the same level as in the healthy control group, with reductions of 22% (P = 0.002) and 28% (P < 0.001), respectively. Diarrhea increased moderately in both GG groups. However, the diarrhea incidence and severity in the GG groups were not statistically significantly different as compared with the RV control group. Moreover, observed diarrhea did not provoke weight loss or death. The RV control group had the largest amount of RV PCR-positive samples among the RV-infected groups, and the live GG group had the smallest amount. Rats receiving live GG had significantly less RV in the colon (P = 0.027) when compared with the RV control group. Live GG was also more effective over dead GG in reducing the quantity of RV from plasma (P = 0.047).

CONCLUSION: Both live and dead GG have beneficial effects in RV infection. GG may increase RV clearance from the body and reduce colon swelling.

Oral administration of a combination of select lactic acid bacteria strains to reduce the Salmonella invasion and inflammation of broiler chicks

One-day-old chicks are susceptible to infection by strains of Salmonella enterica subspecies. Because multistrain probiotics are suggested to be more effective than monostrain probiotics due to the additive and synergistic effects, in this study, we prepared a multistrain formula A (MFA) consisting of 4 lactic acid bacteria (LAB) strains selected by enhancing the TNF-α production for mouse macrophage 264.7 cells. The antagonistic effect of this MFA against the cecal colonization, viscera invasiveness, as well as the inflammation of 1-d-old chicks challenged with Salmonella Typhimurium were then assayed. One-day-old chicks were fed with MFA from d 1 to d 3, and on d 4, chicks were challenged with Salmonella Typhimurium (200 μL, 10(6) cfu/mL). The livers, spleens, and cecal tonsils of chicks were then removed on d 3 and 6 postinfection. Compared with the multistrain formula B (MFB) which consisted of LAB strains selected at random, the efficacy of MFA to reduce the Salmonella counts recovered from the cecal tonsils, spleens, and livers of chicks were significantly higher. Moreover, when the levels of proinflammatory cytokines, such as IL-1β, IL-6, interferon (IFN)-γ, and anti-inflmmatory cytokine, that is, IL-10, in cecal tonsils were measured by reverse-transcription real-time quantitative PCR; it was found that chicks fed with MFA for 3 d had lower levels of IL-1β, IL-6, IFN-γ and a higher level of IL-10 in the cecal tonsils of chicks as compared with those of the chicks fed with MFB or without LAB. These results suggest that multistrain probiotics consisting of LAB strains selected by immunomodulatory activity and adherence are more effective than those consisting of strains selected at random in antagonistic effect against Salmonella colonization, invasion, and the induced inflammation.

Multifaceted attributes of dairy propionibacteria: a review

Dairy propionibacteria are Generally Recognized as Safe (GRAS) status microorganisms which have been traditionally used for the manufacture of Swiss type cheeses. In the last two decades various added features and functionalities have been discovered and developed from these bacteria. Propionibacteria are robust organisms with remarkable adaptability to technological and physiological stress conditions. Besides, they also display a multitude of health promoting properties like modulation of gut microbiota, improved gut physiology and immunomodulation suggesting their promising probiotic potential. Propionibacteria produce an interestingly wide range of functional biomolecules like B group vitamins, trehalose, conjugated linoleic acid, propionic acid, bacteriocins, bifidogenic factors etc. These bacteria are thus now being explored for designing novel functional foods as well as for industrial production of nutraceuticals. Growing interest in these bacteria is fueled by the first whole genome sequencing of a Propionibacterium freudenreichii strain providing a platform for better understanding of various pathways and further improvement in related process technologies.

Probiotic viability - does it matter?

Probiotics are viable by definition, and viability of probiotics is often considered to be a prerequisite for the health benefits. Indeed, the overwhelming majority of clinical studies in the field have been performed with viable probiotics. However, it has also been speculated that some of the mechanisms behind the probiotic health effects may not be dependent on the viability of the cells and, therefore, is also possible that also non-viable probiotics could have some health benefits. The efficacy of non-viable probiotics has been assessed in a limited number of studies, with varying success. While it is clear that viable probiotics are more effective than non-viable probiotics and that, in many cases, viability is indeed a prerequisite for the health benefit, there are also some cases where it appears that non-viable probiotics could also have beneficial effects on human health.

Heat-killed lactic acid bacteria enhance immunomodulatory potential by skewing the immune response toward Th1 polarization

Heat-killed lactic acid bacteria not only possess immunomodulatory functions but also provide the advantages of longer product shelf life, easier storage, and more convenient transportation. To establish appropriate heat treatments for the industrial preparation of probiotics with immunomodulatory effects, 4 different heat treatments were used to kill 11 strains of lactic acid bacteria. Comparisons among the strains and with viable forms were carried out in terms of immunomodulatory activity and adhesion to Caco-2 cells. Field-emission scanning electron microscope (FE-SEM) was employed to observe morphological changes in bacteria after heating. Among the 11 viable strains, Lactobacillus gasseri AI-88 was the strongest inducer of interferon-gamma (IFN)-γ and interleukin (IL)-12p70 production. However, after heat treatments its stimulatory ability was attenuated. Heat-killed Enterococcus faecalis YM-73 and Lactobacillus salivarius AP-32 strains showed enhanced stimulation of IFN-γ and IL-12p70 secretion and coincidental decrease in IL-13 production. The adhesion of lactic acid bacteria to Caco-2 cells decreased with increases in temperature. However, heat exposure did not influence immunomodulatory activity. With rising temperature, roughness and unevenness of bacterial cell surfaces increased significantly. The results indicated that heat-killed E. faecalis YM-73 and L. salivarius AP-32 have immunomodulatory ability via increased Th1-associated cytokines and reduced Th2-associated cytokines, switching the immune response from a Th2 toward a Th1 response. These 2 heat-killed strains have the potential for development as commercial products.