Live probiotics protect intestinal epithelial cells from the effects of infection with enteroinvasive Escherichia coli (EIEC)

Mechanisms for Lactobacillus rhamnosus treatment of intestinal infection by drug-resistant Escherichia coli

Reducing the viability of pathogens may also play an important role for the therapeutic effects of Lactobacillus rhamnosus SHA113 against multiple-drug-resistant E. coli, as well as influencing on the intestinal integrity and functions of animals.

Lactobacillus plantarum ameliorates tumour necrosis factor-induced bacterial translocation in Caco-2 cells by regulation of TLR4 expression

Purpose. Translocation of bacteria across the intestinal barrier is important in the pathogenesis of systemic sepsis. In inflammatory conditions, commensal bacteria exploit transcytotic pathways to cross the intestinal epithelium in a TLR4-dependent manner. The aim of this study was to test the hypothesis that Lactobacillus plantarum ameliorates tumour necrosis factor-induced bacterial translocation by regulation of Toll-like receptor-4 expression.Methodology. L. plantarum strains were investigated to determine their capacity to inhibit the initial adhesion of Escherichia coli B5 to Caco-2 cells. The inhibitory effects of L. plantarum on TNF-α-induced E. coli B5 translocation across Caco-2 cells were studied. Barrier function and integrity were simultaneously assessed by transepithelial electrical resistance, HRP permeability, LDH release and distribution of tight junctional proteins. Expression of TLR4 was assessed by RT-PCR.Results/Key findings. Pretreatment of monolayers with L. plantarum L2 led to a significant decrease in E. coli B5 adhesion and cell internalization (P<0.01). Exposure to TNF-α for six hours caused a significant increase in E. coli B5 translocation across Caco-2 cells, which was uncoupled from increases in paracellular permeability and disruption of tight junction proteins. Manipulations that induced bacterial translocation were associated with a marked increase in TLR4 mRNA expression and IL-8 secretion. L. plantarum L2 significantly abrogated TNF-α-induced bacterial translocation of E. coli B5, and also downregulated expression of TLR4 and IL-8 in intestinal epithelial cells.Conclusion. Live L. plantarum L2 can inhibit TNF-α-induced transcellular bacterial translocation via regulation of TLR4 expression.

Probiotic potential of Lactobacillus on the intestinal microflora against Escherichia coli induced mice model through high-throughput sequencing

The aim of this study was to evaluate the antibacterial potential of Lactobacillus screened from Tibetan yaks on clinical symptoms and intestinal microflora in enteroinvasive Escherichia coli (EIEC) induced mice model. In vitro study, Lactobacillus reuteri (LR1) exhibited stronger resistance to acid and bile and inhibited the growth of EIEC than Lactobacillus mucosae (LM1). The mice were randomly divided into four groups i.e. the LR1 group (LR1 1 × 10⁹ CFU/day), LM1 group (LM1 1 × 10⁹ CFU/day), blank control group and control group. Mice in control, LR1, and LM1 groups were challenged with EIEC on day 23. The body weight in the control and LM1 groups were significantly decreased after the infection with EIEC (P < 0.05), whereas the body weight of mice in the LR1 group did not change significantly (P > 0.05). The lowest diarrhea rate was recorded in the LR1 group after infection with EIEC. The results showed that the number of pathogens in the control group was higher than that in the experimental groups. The sequence analysis and OTU classification showed that the duodenum, ileum, and cecum of mice in the LR1 group had the highest number of OTUs compared with other groups. Whereas, the diversity analysis showed that in duodenum, ileum and cecum of mice in the LR1 group had the highest abundance and diversity. The composition of intestinal microbes indicated the presence of high proportions of Firmicutes, Proteobacteria and Bacteroidetes. Heat map analysis indicated high abundance of Bdello vibrio in the duodenum of mice in the LR1 group, while many pathogens were found in the different part of intestines in the control group, such as Streptococcus, Clostridium and Pseudomonas. In conclusion, pre-supplementation of LR1 alleviate the clinical symptoms caused by E. coli, and promote a healthy gut flora.

Microbial Mechanistic Insights into the Role of Sweet Potato Vine on Improving Health in Chinese Meishan Gilt Model

Simple Summary

Sweet potato vine as a source of fiber had been used in China for many years. We investigated the effects of fresh sweet potato vine on intestinal and plasma metabolites as well as colon microbial composition in Chinese Meishan gilts. Results suggest that sweet potato vine promoted intestinal muscle development, decreased gut permeability, endotoxin and pro-inflammatory cytokines concentrations, and increased butyrate production as well as beneficial flora, thus improving gut health.

Abstract

This study explored the impact of fresh sweet potato vine on the growth as well as the metabolites and colon microbial composition in Chinese Meishan gilt. Twenty Meishan gilts (body weight 30 ± 0.18 kg, n = 10 per treatment) were randomly assigned to a control (CON) or sweet potato vine (SPV) supplementation diet treatment. Gilts were housed in individual stalls. In the SPV treatment, 2 kg fresh sweet potato vine was used instead of 0.18 kg basal diet which provided the same amount of digestive energy and crude protein with the exception of crude fiber (CON, 51.00 g/d vs. SPV, 73.94 g/d) in terms of dry matter intake. Gilts were slaughtered and samples were collected on day 19 after the third estrus cycle. The SPV treatment tended to increase slaughter weight of gilts (p = 0.07); it also increased (p < 0.05) gastrointestinal tract weight and intestinal muscle layer thickness. SPV treatment also decreased (p < 0.05) carcass yield and subcutaneous adipose tissue. The concentration of zonulin and endotoxin in plasma was decreased (p < 0.05) as the gilt consumed the SPV diet. Colonic fecal concentrations of endotoxin, lipocalin-2, and tumor necrosis factor-α (TNF-α) were decreased (p < 0.05), and interleukin-10 (IL-10) was increased (p < 0.05) in the SPV treatment. Butyric acid and acetate concentration in colonic content as well as acetate concentration in caecal content were increased (p < 0.05) in the SPV treatment. Furthermore, the expression of carnitine palmityl transferase (CPT-1) and peroxisome proliferator-activated receptor-α (PPAR-α) in gilt liver in SPV treatment was increased (p < 0.05) in comparison with CON treatment. Meanwhile, the composition of the colon microbes was also altered by SPV; representative changes included an increase in Lactobacillus, Bacteroides, Roseburia, and Lachnospira. These results indicate that gilt fed with sweet potato vine had decreased gut permeability, endotoxin and pro-inflammatory cytokines concentrations; colonic fecal microbiota was also changed, which may be further beneficial to the intestinal health of Chinese Meishan gilt.

Could probiotics be the panacea alternative to the use of antimicrobials in livestock diets?

Probiotics are most frequently derived from the natural microbiota of healthy animals. These bacteria and their metabolic products are viewed as nutritional tools for promoting animal health and productivity, disease prevention and therapy, and food safety in an era defined by increasingly widespread antimicrobial resistance in bacterial pathogens. In contemporary livestock production, antimicrobial usage is indispensable for animal welfare, and employed to enhance growth and feed efficiency. Given the importance of antimicrobials in both human and veterinary medicine, their effective replacement with direct-fed microbials or probiotics could help reduce antimicrobial use, perhaps restoring or extending the usefulness of these precious drugs against serious infections. Thus, probiotic research in livestock is rapidly evolving, aspiring to produce local and systemic health benefits on par with antimicrobials. Although many studies have clearly demonstrated the potential of probiotics to positively affect animal health and inhibit pathogens, experimental evidence suggests that probiotics' successes are modest, conditional, strain-dependent, and transient. Here, we explore current understanding, trends, and emerging applications of probiotic research and usage in major livestock species, and highlight successes in animal health and performance.

Alteration of Gut Microbiota in Inflammatory Bowel Disease (IBD): Cause or Consequence? IBD Treatment Targeting the Gut Microbiome

Inflammatory bowel disease (IBD) is a chronic complex inflammatory gut pathological condition, examples of which include Crohn’s disease (CD) and ulcerative colitis (UC), which is associated with significant morbidity. Although the etiology of IBD is unknown, gut microbiota alteration (dysbiosis) is considered a novel factor involved in the pathogenesis of IBD. The gut microbiota acts as a metabolic organ and contributes to human health by performing various physiological functions; deviation in the gut flora composition is involved in various disease pathologies, including IBD. This review aims to summarize the current knowledge of gut microbiota alteration in IBD and how this contributes to intestinal inflammation, as well as explore the potential role of gut microbiota-based treatment approaches for the prevention and treatment of IBD. The current literature has clearly demonstrated a perturbation of the gut microbiota in IBD patients and mice colitis models, but a clear causal link of cause and effect has not yet been presented. In addition, gut microbiota-based therapeutic approaches have also shown good evidence of their effects in the amelioration of colitis in animal models (mice) and IBD patients, which indicates that gut flora might be a new promising therapeutic target for the treatment of IBD. However, insufficient data and confusing results from previous studies have led to a failure to define a core microbiome associated with IBD and the hidden mechanism of pathogenesis, which suggests that well-designed randomized control trials and mouse models are required for further research. In addition, a better understanding of this ecosystem will also determine the role of prebiotics and probiotics as therapeutic agents in the management of IBD.

Downregulation of Salmonella Virulence Gene Expression During Invasion of Epithelial Cells Treated with Lactococcus lactis subsp. cremoris JFR1 Requires OppA

Invasion of Salmonella into host intestinal epithelial cells requires the expression of virulence genes. In this study, cell culture models of human intestinal cells (mucus-producing HT29-MTX cells, absorptive Caco-2 cells, and combined cocultures of the two) were used to determine the effects of Lactococcus lactis subsp. cremoris treatments (exopolysaccharide producing and nonproducing strains) on the virulence gene expression of Salmonella Typhimurium and its mutant lacking the oligopeptide permease subunit A (ΔoppA). During the course of epithelial cell (HT29-MTX, Caco-2, and combined) infection by Salmonella Typhimurium DT104, improved barrier function was reflected by increased transepithelial electrical resistance in cells treated with both strains of L. lactis subsp. cremoris. In addition, virulence gene expression was downregulated, accompanied with lower numbers of invasive bacteria into epithelial cells in the presence of L. lactis subsp. cremoris treatments. Similarly, virulence gene expression of Salmonella was also suppressed when coincubated with overnight cultures of both L. lactis subsp. cremoris strains in the absence of epithelial cells. However, in medium or in the presence of cell cultures, Salmonella lacking the OppA permease function remained virulent. HT29-MTX cells and combined cultures stimulated by Salmonella Typhimurium DT104 showed significantly lower secretion levels of pro-inflammatory cytokine IL-8 after treatment with L. lactis subsp. cremoris cell suspensions. Contrarily, these responses were not observed during infection with S. Typhimurium ΔoppA. Both the exopolysaccharide producing and nonproducing strains of L. lactis subsp. cremoris JFR1 exhibited an antivirulence effect against S. Typhimurium DT104 although no significant difference between the two strains was observed. Our results show that an intact peptide transporter is essential for the suppression of Salmonella virulence genes which leads to the protection of the barrier function in the cell culture models studied.

Cathelicidin- derived PR39 protects enterohemorrhagic Escherichia coli O157:H7 challenged mice by improving epithelial function and balancing the microbiota in the intestine

The zoonotic enterohaemorrhagic Escherichia coli (EHEC) O157:H7 can disrupt intestinal epithelial barrier function and in turn leading to serious intestinal and systemic disease. PR39 could effectively inhibit the growth of Gram-negative bacteria, but there is little knowledge of its effects on intestinal barrier function and the microbiota in E. coli-challenged mice. In this study, an intestinal disease caused by EHEC O157:H7 was established, to analyze the effect of PR39 on EHEC O157:H7 induced intestinal epithelial barrier injury and disorder. Interestingly, PR39 attenuated EHEC O157:H7-induced systemic symptoms and significantly decreased mortality and the degree of E. coli shedding in faeces. Furthermore, the infiltration index of macrophages and neutrophils in intestine of the PR39 treatment group were obviously attenuated, along with the level of apoptosis. PR39 treatment group had distinctly improved tight junction associated proteins’ expression after EHEC O157:H7 caused injury. Additionally, the sequencing analysis of cecum microbiota showed that PR39 altered the abnormal increase in Bacteroides caused by EHEC O157:H7 and promoted the growth of probiotics such as Lactobacillus. In conclusion, cathelicidin-derived PR39 could effectively improve EHEC O157:H7-induced epithelial barrier injury, and dysfunction of immune and microbiota homeostasis in the intestinal tract, indicating that PR39 could be an excellent potential drug for zoonotic EHEC O157:H7-related intestinal disease.

Effect of heat-killed Streptococcus thermophilus on type 2 diabetes rats

BACKGROUND AND AIMS

The link between gut microbiota and type 2 diabetes (T2D) has been addressed by numerous studies. Streptococcus thermophilus from fermented milk products, has been used as a probiotic in previous research. However, whether heat-killed S. thermophilus can improve the glycemic parameters of diabetic rats remains unanswered. In this study, we evaluated the effect of heat-killed S. thermophilus on T2D model rats and the potential mechanisms of the effect.

METHODS

Zucker diabetic fatty (ZDF) rats were used to generate a diabetic rat model induced by feeding a high-fat diet. Heat-killed S. thermophilus were orally administered to normal and diabetic rats for 12 weeks. Intestinal microbiota analysis, histology analysis, oral glucose tolerance test and measurement of inflammatory factors were performed.

RESULTS

We found that heat-killed S. thermophilus treatment reduced fasting blood glucose levels and alleviated glucose intolerance and total cholesterol in diabetic ZDF rats. Additionally, heat-killed S. thermophilus increased the interleukin 10 while reducing the levels of lipopolysaccharide, interleukin 6, and tumor necrosis factor-α in diabetic ZDF rats. The heat-killed S. thermophilus treatment can normalize the structure of the intestinal and colon mucosal layer of diabetic rats. The characteristics of the gut microbiota in heat-killed S. thermophilus-treated and control rats were similar. At the genus level, the abundances of beneficial bacteria, including Ruminococcaceae, Veillonella, Coprococcus, and Bamesiella, were all significantly elevated by heat-killed S. thermophilus treatment in ZDF diabetic rats.

CONCLUSION

Our study supports the hypothesis that treatment with heat-killed S. thermophilus could effectively improve glycemic parameters in T2D model rats. In addition, the potential mechanisms underlying the protection maybe include changing the composition of gut microbiota, reinforcing the intestinal epithelial barrier and the immunity of the intestinal mucosa, decreasing the level of inflammation, and then reducing the insulin resistance.

Growth, health, rumen fermentation, and bacterial community of Holstein calves fed Lactobacillus rhamnosus GG during the preweaning stage1

The aim of this study was to determine if feeding Lactobacillus rhamnosus GG (GG, ATCC 53013) to neonatal calves would alter their growth, health, rumen fermentation, and bacterial community composition during the preweaning stage; we hypothesized that it would. Twenty-four male Holstein calves were blocked and randomly assigned to 1 of 2 treatment groups: 1) untreated control (CON), or 2) treated with 1 × 1010 cfu/d of a GG suspension (GG). Calves received GG daily, mixed with the milk replacer in the morning feed for 6 wk. Starter and alfalfa hay intakes, as well as feces and respiratory scores, were recorded daily, while body weight and structures were measured weekly. Blood, rumen fluid, and feces samples were collected, from which relevant indicators were detected. The results showed that the administration of GG significantly increased voluntary starter intake (P = 0.023) and ADG (P = 0.035) of the calves. The fecal score (P = 0.018) was lower and the β-hydroxybutyric concentration in the plasma tended to increase (P = 0.092) in calves treated with GG. The pH of the rumen fluid in calves fed GG was lower (P = 0.007), which might be attributable to the tendency (P = 0.083) for total volatile fatty acids concentration to increase. Administration of GG significantly increased the amylase, protease activity, and the microbial protein concentrations (P = 0.043, P = 0.036, and P = 0.044, respectively) in the rumen fluids. Furthermore, GG treatment altered the dominant bacteria order and relative abundance of the bacteria families in the rumen fluids. The microbial diversity indices were significantly affected by GG administration. In conclusion, the neonatal calves fed GG before weaning increased their voluntary starter intake and growth performance, improved the rumen fermentation, and regulated the pattern to normally increase the propionate and butyrate concentrations. Administration of GG also diversified the bacterial community composition in the rumen, and regulated the balance of rumen and intestinal microorganisms. These results indicated that feeding calves GG were beneficial to the rumen development and early weaning.

Laryngotracheal Microbiota in Adult Laryngotracheal Stenosis

Laryngotracheal stenosis is an obstructive respiratory disease that leads to voicing difficulties and dyspnea with potential life-threatening consequences. The majority of incidences are due to iatrogenic etiology from endotracheal tube intubation; however, airway scarring also has idiopathic causes. While recent evidence suggests a microbial contribution to mucosal inflammation, the microbiota associated with different types of stenosis has not been characterized. High-throughput sequencing of the V4 region of the16S rRNA gene was performed to characterize the microbial communities of 61 swab samples from 17 iatrogenic and 10 adult idiopathic stenosis patients. Nonscar swabs from stenosis patients were internal controls, and eight swabs from four patients without stenosis represented external controls. Significant differences in diversity were observed between scar and nonscar samples and among sample sites, with decreased diversity detected in scar samples and the glottis region. Permutational analysis of variance (PERMANOVA) results revealed significant differences in community composition for scar versus nonscar samples, etiology type, sample site, groups (iatrogenic, idiopathic, and internal and external controls), and individual patients. Pairwise Spearman's correlation revealed a strong inverse correlation between Prevotella and Streptococcus among all samples. Finally, bacteria in the family Moraxellaceae were found to be distinctly associated with idiopathic stenosis samples in comparison with external controls. Our findings suggest that specific microbiota and community shifts are present with laryngotracheal stenosis in adults, with members of the family Moraxellaceae, including the known pathogens Moraxella and Acinetobacter, identified in idiopathic scar. Further work is warranted to elucidate the contributing role of bacteria on the pathogenesis of laryngotracheal stenosis.IMPORTANCE The laryngotracheal region resides at the intersection between the heavily studied nasal cavity and lungs; however, examination of the microbiome in chronic inflammatory conditions of the subglottis and trachea remains scarce. To date, studies have focused on the microbiota of the vocal folds, or the glottis, for laryngeal carcinoma, as well as healthy larynges, benign vocal fold lesions, and larynges exposed to smoking and refluxate. In this study, we seek to examine the structure and composition of the microbial community in adult laryngotracheal stenosis of various etiologies. Due to the heterogeneity among the underlying pathogenesis mechanisms and clinical outcomes seen in laryngotracheal stenosis disease, we hypothesized that different microbial profiles will be detected among various stenosis etiology types. Understanding differences in the microbiota for subglottic stenosis subtypes may shed light upon etiology-specific biomarker identification and offer novel insights into management approaches for this debilitating disease.

Oral Administration of Bovine Lactoferrin-Derived Lactoferricin (Lfcin) B Could Attenuate Enterohemorrhagic Escherichia coli O157:H7 Induced Intestinal Disease through Improving Intestinal Barrier Function and Microbiota

Lactoferricin (Lfcin) B, derived from lactoferrin in whey, has attracted considerable attention because of its multiple biological functions. Zoonotic enterohemorrhagic Escherichia coli (EHEC) O157:H7 has adverse effects on intestinal epithelial barrier function, leading to serious intestinal disease. In this study, the EHEC O157:H7-induced intestinal dysfunction model was developed to investigate the effects of Lfcin B on EHEC O157:H7-induced epithelial barrier disruption and microbiota dysbiosis. Results showed that the inflammatory infiltration indexes in the jejunum of Lfcin B-treated animals were significantly decreased. Lfcin B administration also significantly improved ZO-1 and occludin expression following O157:H7-induced injury. Finally, microbiota analysis of the cecal samples revealed that Lfcin B inhibited the O157:H7-induced abnormal increase in Bacteroides. Therefore, Lfcin B efficiently attenuated O157:H7-induced epithelial barrier damage and dysregulation of inflammation status, while maintaining microbiota homeostasis in the intestine, indicating that it may be an excellent food source for prevention and therapy of EHEC O157:H7-related intestinal dysfunction.

The Effects of Fecal Donors with Different Feeding Patterns on Diarrhea in a Patient Undergoing Hematopoietic Stem Cell Transplantation

Almost 90% of patients undergoing hematopoietic stem cell transplantation (HSCT) experience diarrheal episodes, which represent a severe, often life-threatening complication for these patients. Although fecal microbiota transplantation (FMT) represents an alternative treatment option for infection-related diarrhea, the application of FMT in HSCT patients is greatly restricted for safety reasons. Furthermore, the therapeutic outcomes of FMT as a diarrhea treatment are somewhat related to the choice of the FMT donor. Here, we comprehensively profiled the dynamic changes in the intestinal microbiota after FMT from two donors with different feeding patterns and the same severely diarrheal recipient undergoing HSCT via a 45-day clinical observation. Importantly, no adverse events attributed to FMT were observed. The stool volume and frequency of the patient were reduced when we used feces from donor #1 (mixed feeding), but these changes were not observed after FMT from donor #2 (exclusive breastfeeding). Interestingly, no obvious differences in overall diversity (Shannon) or richness (Chao1) between the two donors were observed. Additionally, Bifidobacterium accounted for 29.9% and 18.1% of OTUs in the stools of donors #1 and #2, respectively. Lactobacillus accounted for 16.3% and 2.9% of the stools of donors #1 and #2, respectively. Furthermore, through longitudinal monitoring of the patient, we identified 6 OTUs that were particularly sensitive to the different FMT complements. Together, we present a case report suggesting that the overall diversity of the intestinal microbiota may not be the only important element in the selection of an effective FMT donor.

The Role of Probiotics and Prebiotics in the Prevention and Treatment of Obesity

Obesity is a global pandemic complex to treat due to its multifactorial pathogenesis-an unhealthy lifestyle, neuronal and hormonal mechanisms, and genetic and epigenetic factors are involved. Scientific evidence supports the idea that obesity and metabolic consequences are strongly related to changes in both the function and composition of gut microbiota, which exert an essential role in modulating energy metabolism. Modifications of gut microbiota composition have been associated with variations in body weight and body mass index. Lifestyle modifications remain as primary therapy for obesity and related metabolic disorders. New therapeutic strategies to treat/prevent obesity have been proposed, based on pre- and/or probiotic modulation of gut microbiota to mimic that found in healthy non-obese subjects. Based on human and animal studies, this review aimed to discuss mechanisms through which gut microbiota could act as a key modifier of obesity and related metabolic complications. Evidence from animal studies and human clinical trials suggesting potential beneficial effects of prebiotic and various probiotic strains on those physical, biochemical, and metabolic parameters related to obesity is presented. As a conclusion, a deeper knowledge about pre-/probiotic mechanisms of action, in combination with adequately powered, randomized controlled follow-up studies, will facilitate the clinical application and development of personalized healthcare strategies.

A More Robust Gut Microbiota in Calorie-Restricted Mice Is Associated with Attenuated Intestinal Injury Caused by the Chemotherapy Drug Cyclophosphamide

Improving the gut microbiota via calorie restriction is beneficial for human health. Our findings showed differential responses between calorie-restricted mice and ad libitum-fed mice. Compared with the ad libitum-fed mice, the calorie-restricted mice were less susceptible to cyclophosphamide side effects otherwise observed on the gut integrity and its microbiota. These results show the potential benefits of manipulating the gut microbiota with CR prior to cancer chemotherapy.

Cyclophosphamide (CTX) is widely used in cancer chemotherapy, but it often induces mucositis, in which the disruption of the gut microbiota might play a pivotal role. Whether the manipulation of the gut microbiota can be used as a strategy to improve CTX-induced mucositis remains to be studied. Here we observed the effects of a 4-week calorie restriction (CR) on CTX-induced mucositis. Compared with ad libitum-fed mice, CR mice showed significantly less mucositis in response to CTX, including lower intestinal permeability, less bacterial translocation, higher number of epithelial stem cells, and less epithelium damage. CTX induced significant shifts of the gut microbiota of the gut microbiota in ad libitum-fed control mice. In contrast, CR mice showed no significant change in their gut microbiota in responding to CTX treatment. CR significantly enriched the gut microbiota in Lactobacillus and Lachnospiraceae which are known to mitigate inflammation and improve gut barrier function. These findings suggest that CR remodeled gut microbiota is more robust and may contribute to attenuate the side effects of cyclophosphamide, which supports the concept that cancer chemotherapy would benefit from strategies targeting the gut microbiota.

Probiotics for preventing postoperative infection in colorectal cancer patients: a systematic review and meta-analysis

PURPOSE

Postoperative infection has seriously affected the prognosis of cancer patients, while probiotics have been increasingly used to prevent postoperative infection in clinical practice. This study aimed to evaluate the preventive effect of probiotics on infection after colorectal cancer (CRC) surgery.

METHODS

Related clinical trial reports were collected from Pubmed, Embase, Cochrane Library as well as China National Knowledge Infrastructure (CNKI) databases. These reports were then strictly screened, and information as well as data were extracted. Finally, the enrolled studies were evaluated by systematic review and meta-analysis using STATA v11 and Revman v5.2.

RESULTS

Probiotics administration contributed to the reduction of overall infection rate after colorectal surgery, with a pooled odds ratio (OR) of 0.51 (95% CI: 0.38-0.68, P = 0.00). Meanwhile, the incidence of incision infection (pooled OR = 0.59, 95% CI 0.39-0.88, P = 0.01) and pneumonia (pooled OR = 0.56, 95% CI 0.32-0.98, P = 0.04) as well as the first flatus time (SMDs = - 0.70, 95% CI - 1.13-- 0.27, P = 0.002) were also reduced by probiotics. In addition, urinary tract infection, anastomotic leakage, and duration of postoperative pyrexia were also analyzed, which displayed no statistical differences compared with those of control.

CONCLUSION

Probiotics have potential efficacy on preventing postoperative infection and related complications in cancer patients undergoing colorectal surgery.

Inhibition of enterohemorrhagic Escherichia coli O157:H7 infection in a gnotobiotic mouse model with pre-colonization by Bacteroides strains

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 has been known to cause outbreaks of hemorrhagic colitis and hemolytic uremic syndrome. We previously demonstrated that intestinal flora contribute to the prevention of EHEC infection in a mouse model. However, it has not yet been determined whether Bacteroides, a predominant genus in the human intestine, contributes to the prevention of EHEC infection. The aim of the present study was to investigate the effect of Bacteroides fragilis (B. fragilis) and Bacteroides vulgatus (B. vulgatus) on EHEC O157:H7 infection in vivo using gnotobiotic mice. These strains were inoculated into germ-free mice to create a gnotobiotic mouse model. EHEC was inoculated into the mice, which were then monitored for 7 days for any change in symptoms. The mice that had been pre-colonized with the Bacteroides strains did not develop lethal EHEC infection, although several inflammatory symptoms were observed in the B. vulgatus pre-colonized group. However, no inflammatory symptoms were identified in the B. fragilis pre-colonized group. Moreover, B. fragilis exerted an inhibitory effect on enterocyte-like cell apoptosis. B. fragilis protected HT29 cells from apoptosis caused by Shiga toxin. In conclusion, the findings of the present study demonstrated that colonization by Bacteroides strains can inhibit EHEC infection.

The Foodborne Strain Lactobacillus fermentum MBC2 Triggers pept-1-Dependent Pro-Longevity Effects in Caenorhabditis elegans

Lactic acid bacteria (LAB) are involved in several food fermentations and many of them provide strain-specific health benefits. Herein, the probiotic potential of the foodborne strain Lactobacillus fermentum MBC2 was investigated through in vitro and in vivo approaches. Caenorhabditis elegans was used as an in vivo model to analyze pro-longevity and anti-aging effects. L. fermentum MBC2 showed a high gut colonization capability compared to E. coli OP50 (OP50) or L.rhamnosus GG (LGG). Moreover, analysis of pumping rate, lipofuscin accumulation, and body bending showed anti-aging effects in L. fermentum MBC2-fed worms. Studies on PEPT-1 mutants demonstrated that pept-1 gene was involved in the anti-aging processes mediated by this bacterial strain through DAF-16, whereas the oxidative stress protection was PEPT-1 independent. Moreover, analysis of acid tolerance, bile tolerance, and antibiotic susceptibility were evaluated. L. fermentum MBC2 exerted beneficial effects on nematode lifespan, influencing energy metabolism and oxidative stress resistance, resulted in being tolerant to acidic pH and able to adhere to Caco-2 cells. Overall, these findings provide new insight for application of this strain in the food industry as a newly isolated functional starter. Furthermore, these results will also shed light on C. elegans molecular players involved in host-microbe interactions.

Probiotics, mechanisms of action, and clinical perspectives for diarrhea management in children

Infectious diarrhea is the second most common cause of morbidity and mortality in children under 5 years of age in the underdeveloped areas of the world. Conventional treatment consists of rehydration, which may be coupled with antimicrobial agents in more severe bacterial infections or with antiprotozoal agents. In the last few decades, research on the use of probiotic strains, such as Lactobacillus rhamnosus GG ATCC 53013 (LGG), Lactobacillus reuteri DSM 17938 and Saccharomyces boulardii, has gained much attention to prevent and treat diarrheal diseases. However, they are rarely used in the clinical routine, perhaps because there are still gaps in the knowledge about the effective benefit to the patient in terms of the reduction of the duration of diarrhea and its prevention. Furthermore, only a few probiotic strains are safely indicated for usage in pediatric practice. This review summarizes the current knowledge on the antimicrobial mechanisms of probiotics on distinct enteropathogens and their role in stimulating host defense mechanisms against intestinal infections. In addition, we highlight the potential of probiotics for the treatment and prevention of diarrhea in children. We conclude that the use of probiotics is beneficial for both the treatment and prevention of diarrhea in children and that the identification of other candidate probiotics might represent an important advance to a greater reduction in hospital stays and to prevent infectious diarrhea in a larger portion of this population.

Effects of Bacillus subtilis C-3102 on production, hatching performance, egg quality, serum antioxidant capacity and immune response of laying breeders

To investigate the supplemental effects of Bacillus subtilis C-3102 on the production, hatching performance, egg quality, serum antioxidant capacity and immune response of laying breeders, a total of 480 Xuefeng black-bone (25-week-old) hens were randomly assigned into four treatment groups: Hens fed the basal diets with 0 (CON), 3.0 × 10⁵ (BS-1), 6.0 × 10⁵  cfu/g (BS-2) and 9.0 × 10⁵ (BS-3) cfu/g of B. subtilis C-3102. As the B. subtilis C-3102 level increased, egg weight (linear, p < 0.01; quadratic, p = 0.003), fertility (linear, p = 0.021; quadratic, p = 0.059), hatchability (linear, p = 0.038; quadratic, p = 0.119) and yolk colour (linear, p = 0.006; quadratic, p = 0.021) increased in a linear or quadratic manner. Yolk index increased quadratically (linear, p = 0.054; quadratic, p = 0.017), and eggshell thickness (linear, p = 0.036; quadratic, p = 0.128), the activity of GSH-Px (linear, p = 0.024; quadratic, p = 0.078), the concentration of IgM (linear, p = 0.016; quadratic, p = 0.056) and the level of AIV-Ab (linear, p = 0.034; quadratic, p = 0.103) in the serum increased linearly as dietary supplementation of B. subtilis C-3102 increased. The results showed that dietary treatments did not affect egg production, feed conversion ratio, egg mass, hatchability of fertile eggs, eggshell-breaking strength, egg-shape index, yolk percentage, Haugh unit, T-SOD, T-AOC, MDA, IgA and IgG concentrations and the level of NDV-Ab in the serum. In conclusion, dietary supplementation of 9.0 × 10⁵  cfu/g B. subtilis C-3102 in laying breeders diets may be a feasible means of effectively increasing egg weight, fertility and hatchability, and improving egg quality such as eggshell thickness, yolk index and yolk colour. Besides, B. subtilis C-3102 can enhance the activity of GSH-Px, the concentration of IgM and the level of AIV-Ab in the serum.

Intestinal in vitro and ex vivo Models to Study Host-Microbiome Interactions and Acute Stressors

The gut microbiome is extremely important for maintaining homeostasis with host intestinal epithelial, neuronal, and immune cells and this host-microbe interaction is critical during times of stress or disease. Environmental, nutritional, and cognitive stress are just a few factors known to influence the gut microbiota and are thought to induce microbial dysbiosis. Research on this bidirectional relationship as it pertains to health and disease is extensive and rapidly expanding in both in vivo and in vitro/ex vivo models. However, far less work has been devoted to studying effects of host-microbe interactions on acute stressors and performance, the underlying mechanisms, and the modulatory effects of different stressors on both the host and the microbiome. Additionally, the use of in vitro/ex vivo models to study the gut microbiome and human performance has not been researched extensively nor reviewed. Therefore, this review aims to examine current evidence concerning the current status of in vitro and ex vivo host models, the impact of acute stressors on gut physiology/microbiota as well as potential impacts on human performance and how we can parlay this information for DoD relevance as well as the broader scientific community. Models reviewed include widely utilized intestinal cell models from human and animal models that have been applied in the past for stress or microbiology research as well as ex vivo organ/tissue culture models and new innovative models including organ-on-a-chip and co-culture models.

Therapeutic Microbiology: The Role of Bifidobacterium breve as Food Supplement for the Prevention/Treatment of Paediatric Diseases

The human intestinal microbiota, establishing a symbiotic relationship with the host, plays a significant role for human health. It is also well known that a disease status is frequently characterized by a dysbiotic condition of the gut microbiota. A probiotic treatment can represent an alternative therapy for enteric disorders and human pathologies not apparently linked to the gastrointestinal tract. Among bifidobacteria, strains of the species Bifidobacterium breve are widely used in paediatrics. B. breve is the dominant species in the gut of breast-fed infants and it has also been isolated from human milk. It has antimicrobial activity against human pathogens, it does not possess transmissible antibiotic resistance traits, it is not cytotoxic and it has immuno-stimulating abilities. This review describes the applications of B. breve strains mainly for the prevention/treatment of paediatric pathologies. The target pathologies range from widespread gut diseases, including diarrhoea and infant colics, to celiac disease, obesity, allergic and neurological disorders. Moreover, B. breve strains are used for the prevention of side infections in preterm newborns and during antibiotic treatments or chemotherapy. With this documentation, we hope to increase knowledge on this species to boost the interest in the emerging discipline known as "therapeutic microbiology".

In vitro Assessment of the Probiotic Properties and Bacteriocinogenic Potential of Pediococcus pentosaceus MZF16 Isolated From Artisanal Tunisian Meat "Dried Ossban"

Pediococcus pentosaceus MZF16 has been isolated from artisanal Tunisian meat so called "Dried Ossban," an original ecological niche, and identified by MALDI-TOF mass spectrometry and 16S rDNA sequencing. This bacterium showed a high tolerance to gastric stress conditions, and toward bile salts. P. pentosaceus MZF16 also demonstrated a hydrophobic surface profile (high adhesion to xylene), autoaggregation, and adhesive abilities to the human intestinal Caco-2/TC7 cell line. These properties may help the bacterium colonizing the gut. Furthermore, MZF16 was found to be resistant to gentamycin and chloramphenicol but did not harbor any transferable resistance determinants and/or virulence genes. The data also demonstrated absence of cytotoxicity of this strain. Conversely, P. pentosaceus MZF16 can slightly stimulate the immune system and enhance the intestinal epithelial barrier function. Moreover, this bacterium has been shown to be highly active against Listeria spp. due to bacteriocin production. Characterization of the bacteriocin by PCR amplification, sequencing and bioinformatic analyses revealed that MZF16 produces a bacteriocin 100% identical to coagulin, a pediocin-like inhibitory substance produced by Bacillus coagulans. To our knowledge, this is the first report that highlights the production of a pediocin 100% identical to coagulin in a Pediococcus strain. As coagulin, pediocin MZF16 has the consensus sequence YYGNGVXCXXXXCXVXXXXA (X denotes any amino acid), which confirms its belonging to class IIa bacteriocins, and its suitability to preserve foods from Listeria monocytogenes development. According to these results, P. pentosaceus MZF16 can be proposed as a probiotic and bioprotective agent for fermented foods, including Tunisian dry meat and sausages. Further investigations will aim to study the behavior of this strain in meat products as a component of functional food.

Lactobacillus rhamnosus GG Protects the Epithelial Barrier of Wistar Rats from the Pepsin-Trypsin-Digested Gliadin (PTG)-Induced Enteropathy

Celiac disease (CD) is a chronic immune-mediated disorder, characterized by enhanced paracellular permeability across the intestinal epithelium. The complex system of intercellular junctions, including tight junctions (TJs) and adherens junctions (AJs), seals together the epithelial cells to form a continuous layer. The improvements in barrier integrity have been related to modifications in intercellular junction protein expression. Polyamines (spermidine, spermine, and putrescine) actively participate in the modulation of the AJ expression. Both in vitro and in vivo studies have demonstrated that also probiotics can promote the integrity and the function of the intestinal barrier. On these bases, the present work investigated the protective effects exerted by Lactobacillus rhamnosus GG (L.GG) against the pepsin-trypsin-digested gliadin (PTG)-induced enteropathy in jejunal tissue samples of Wistar rats. In particular, the probiotic effects have been evaluated on the intestinal mucosal architecture, polyamine metabolism and intercellular junction protein expression (ZO-1, Occludin, Claudin-1, β-catenin and E-cadherin). The results from this study indicate that L.GG protects the intestinal mucosa of rats from PTG-induced damage, by preventing the reduction of the expression of the intercellular junction proteins. Consequently, a role for L.GG in the therapeutic management of the gluten-related disorders in humans could be hypothesized.

Probiotics and the Gut Immune System: Indirect Regulation

The gastrointestinal tract (GIT) represents the largest interface between the human organism and the external environment. In the lumen and upper part of the mucus layer, this organ hosts an enormous number of microorganisms whose composition affects the functions of the epithelial barrier and the gut immune system. Consequentially, the microorganisms in the GIT influence the health status of the organism. Probiotics are living microorganisms which, in specific conditions, confer a health benefit to the host. Among others, probiotics have immunomodulatory properties that usually act directly by (a) increasing the activity of macrophages or natural killer cells, (b) modulating the secretion of immunoglobulins or cytokines, or indirectly by (c) enhancing the gut epithelial barrier, (d) altering the mucus secretion, and (e) competitive exclusion of other (pathogenic) bacteria. This review focuses on specific bacteria strains with indirect immunomodulatory properties. Particularly, we describe here the mechanisms through which specific probiotics enhance the gut epithelial barrier and modulate mucus production. Moreover, we describe the antimicrobial properties of specific bacteria strains. Recent data suggest that multiple pathologies are associated with an unbalanced gut microflora (dysbiosis). Although the cause-effect relationship between pathology and gut microflora is not yet well established, consumption of specific probiotics may represent a powerful tool to re-establish gut homeostasis and promote gut health.

Probiotics for the airways: Potential to improve epithelial and immune homeostasis

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefit on the host. The therapeutic effects of probiotics have been mostly studied in the gastrointestinal tract, but recent evidence points toward the potential of these bacteria to prevent and/or treat chronic airway diseases. In this review, possible mechanisms of action of probiotics in the airways are described, with a particular focus on their capacity to modulate the epithelial barrier function and their mode of interaction with the immune system. Indeed, probiotic bacteria, mostly lactobacilli, can promote the expression and regulation of tight junctions and adherence junctions, resulting in the restoration of a defective epithelial barrier. These bacteria interact with the epithelial barrier and immune cells through pattern recognition receptors, such as Toll-like receptors, which upon activation can stimulate or suppress various immune responses. Finally, the clinical potential of probiotics to treat inflammatory diseases of the upper and lower respiratory tract, and the difference between their mode of application (eg, oral or nasal) are discussed here.

A Review: The Fate of Bacteriocins in the Human Gastro-Intestinal Tract: Do They Cross the Gut-Blood Barrier?

The intestinal barrier, consisting of the vascular endothelium, epithelial cell lining, and mucus layer, covers a surface of about 400 m2. The integrity of the gut wall is sustained by transcellular proteins forming tight junctions between the epithelial cells. Protected by three layers of mucin, the gut wall forms a non-permeable barrier, keeping digestive enzymes and microorganisms within the luminal space, separate from the blood stream. Microorganisms colonizing the gut may produce bacteriocins in an attempt to outcompete pathogens. Production of bacteriocins in a harsh and complex environment such as the gastro-intestinal tract (GIT) may be below minimal inhibitory concentration (MIC) levels. At such low levels, the stability of bacteriocins may be compromised. Despite this, most bacteria in the gut have the ability to produce bacteriocins, distributed throughout the GIT. With most antimicrobial studies being performed in vitro, we know little about the migration of bacteriocins across epithelial barriers. The behavior of bacteriocins in the GIT is studied ex vivo, using models, flow cells, or membranes resembling the gut wall. Furthermore, little is known about the effect bacteriocins have on the immune system. It is generally believed that the peptides will be destroyed by macrophages once they cross the gut wall. Studies done on the survival of neurotherapeutic peptides and their crossing of the brain-blood barrier, along with other studies on small peptides intravenously injected, may provide some answers. In this review, the stability of bacteriocins in the GIT, their effect on gut epithelial cells, and their ability to cross epithelial cells are discussed. These are important questions to address in the light of recent papers advocating the use of bacteriocins as possible alternatives to, or used in combination with, antibiotics.

Lactobacillus acidophilus Alleviated Salmonella-Induced Goblet Cells Loss and Colitis by Notch Pathway

SCOPE

The intestinal mucosal barrier, including the mucus layer, protects against invasion of enteropathogens, thereby inhibiting infection. In this study, the protective effect of Lactobacillus on the intestinal barrier against Salmonella infection is investigated. The underlying mechanism of its effect, specifically on the regulation of goblet cells through the Notch pathway, is also elucidated.

METHODS AND RESULTS

Here, the protective effect of Lactobacillus on alleviating changes in the intestinal barrier caused by Salmonella infection is explored. It has been found that Salmonella typhimurium colonizes the colon and damages colonic mucosa. However, Lactobacillus acidophilus ATCC 4356 alleviates the colitis caused by Salmonella infection. Moreover, S. typhimurium infection causes colonic crypt hyperplasia with increased PCNA⁺ cells, while L. acidophilus administration resolves these pathological changes. In addition, it has been further demonstrated that Salmonella results in severe colitis associated with goblet cells, and Lactobacillus improves colitis similarly associated with goblet cells. Salmonella infection induces goblet cell loss and reduces MUC2 expression by increasing Dll1, Dll4, and HES1 expression, while L. acidophilus reverses epithelial damage by balancing the Notch pathway.

CONCLUSION

The study demonstrates that colitis improvement is controlled by Lactobacillus ATCC 4356 by regulation of the Notch pathway; this finding will be useful for prevention against animal S. typhimurium infection.

The role of adjuvant probiotics to attenuate intestinal inflammatory responses due to cancer treatments

Chemotherapy and radiotherapy treatment regimens for gastrointestinal, peritoneal and pelvic tumours can disrupt the intestinal microbiome and intestinal epithelia. Such disturbances can provoke symptoms such as diarrhoea, nausea and vomiting. Chemotherapy and radiotherapy induced gastrointestinal toxicity aggravating intestinal microbiome dysbiosis is postulated to adversely alter the intestinal microbiome, with a consequent induced pro-inflammatory effect that disrupts the intestinal microbiome-epithelia-mucosal immunity axis. Although not widely recognised, the intestinal mucosa is the largest and most densely and dynamically populated immune-environment. Cancer treatment adverse effects that affect intestinal and mucosal cells inadvertently target and disrupt resident intestinal macrophages, the cells that marshal immune activity in the intestinal mucosa by shaping pro-inflammatory and anti-inflammatory activities to control and eradicate infectious insults and maintain local homeostasis. Pathobionts (bacteria capable of pathogenic pro-inflammatory activity) and noxious environmental and bacterial antigens use the intestinal epithelia and gap junctions as a point of entry into the systemic circulation. This translocation movement promotes toxic sequelae that obstruct intestinal macrophage functions resulting in uncontrolled local and systemic pro-inflammatory activity, loss of phagocytic function and loss of expression of tight junction proteins. Probiotic bacteria as an adjunctive treatment shows efficacy in ameliorating enteropathies such as mucositis/diarrhoea resulting from chemotherapy or radiotherapy regimens. As such we posit that an important benefit that warrants a further focused research effort is the administration of adjuvant probiotics to help reduce the incidence of febrile neutropenia.

Probiotics interaction with foodborne pathogens: a potential alternative to antibiotics and future challenges

Antibiotics are a key tool used nowadays in health care industry to fight against bacterial infections; however, repeated antibiotic use or misuses, have led to bacterial resistance, causing significant threats for many people with common bacterial infections. The use of probiotics to enhance gastrointestinal health has been proposed for many years. In recent years, there has been an increasing interest in the use of probiotic bacteria as alternatives for antibiotics for preventing or treating various intestinal infections. Several important underlying mechanisms responsible for the antagonistic effects of probiotics on different microorganisms include: (1) competitive exclusion for adhesion sites and nutritional sources; (2) secretion of antimicrobial substances; (3) enhancement of intestinal barrier function; and (4) immunomodulation. However, their mode of action is not very well understood and therefore a clearer understanding of these mechanisms is necessitated. This will enable appropriate probiotic strains to be selected for particular applications and may reveal new probiotic functions. The goal of this review was to highlight some studies from literature describing the probiotic interaction with several major foodborne pathogens, as well as explore the mechanisms for such probiotic-pathogen interaction. The review will conclude by presenting future perspective and challenges of probiotic application in food products.

Lactobacillus reuteri LR1 Improved Expression of Genes of Tight Junction Proteins via the MLCK Pathway in IPEC-1 Cells during Infection with Enterotoxigenic Escherichia coli K88

Intestinal epithelial barrier damage disrupts immune homeostasis and leads to many intestinal disorders. Lactobacillus reuteri strains have probiotic functions in their modulation of the microbiota and immune system in intestines. In this study, the effects of L. reuteri LR1, a new strain isolated from the feces of weaning piglets, on intestinal epithelial barrier damage in IPEC-1 cells caused by challenge with enterotoxigenic Escherichia coli (ETEC) K88 were examined. It was found that L. reuteri LR1, in large part, offset the ETEC K88-induced increase in permeability of IPEC-1 cell monolayers and decreased the adhesion and invasion of the coliform in IPEC-1 cells. In addition, L. reuteri LR1 increased transcript abundance and protein contents of tight junction (TJ) proteins zonula occluden-1 (ZO-1) and occludin in ETEC K88-infected IPEC-1 cells, whereas it had no effects on claudin-1 and F-actin expression. Using colloidal gold immunoelectron microscopy, these effects of L. reuteri LR1 on ZO-1 and occludin content in IPEC-1 cells were confirmed. By using ML-7, a selective inhibitor of myosin light-chain kinase (MLCK), the beneficial effect of L. reuteri LR1 on contents of ZO-1 and occludin was shown to be dependent on the MLCK pathway. In conclusion, L. reuteri LR1 had beneficial effects on epithelial barrier function consistent with increasing ZO-1 and occludin expression via a MLCK-dependent manner in IPEC-1 cells during challenge with ETEC K88.

Evaluation of Probiotic Properties and Safety of Enterococcus faecium Isolated From Artisanal Tunisian Meat "Dried Ossban"

Enterococcus faecium strains were isolated from an original biotope, artisanal dried Tunisian meat “Dried Ossban,” and evaluated for safety and capacity as probiotics. Gram-positive, catalase negative, and bacteriocin-producing bacteria were screened using selective microbiological media. All isolates were identified by phenotypic and molecular tools. Five E. faecium strains (MZF1, MZF2, MZF3, MZF4, and MZF5) were selected and further assessed for their probiotic properties. They were found to be resistant to the physiological concentrations of bile salts, and the harsh conditions of the gastrointestinal tract, and showed autoaggregation and adhesion ability. All these isolates possess at least one enterocin and could efficiently inhibit the growth of Listeria innocua HPB13. The analysis of their safety profile revealed for almost all the strains the absence of cytotoxicity and virulence determinants, and susceptibility to clinically important antibiotics such as vancomycin. These data suggest that these bacteria, isolated from “Dried Ossban,” do not present a risk to human health, and may be considered as interesting candidates for future use as probiotics and bioprotective cultures for application in the food and/or feed industries.

Metabolism of Caprine Milk Carbohydrates by Probiotic Bacteria and Caco-2:HT29⁻MTX Epithelial Co-Cultures and Their Impact on Intestinal Barrier Integrity

The development and maturation of the neonatal intestine is generally influenced by diet and commensal bacteria, the composition of which, in turn, can be influenced by the diet. Colonisation of the neonatal intestine by probiotic Lactobacillus strains can strengthen, preserve, and improve barrier integrity, and adherence of probiotics to the intestinal epithelium can be influenced by the available carbon sources. The goal of the present study was to examine the role of probiotic lactobacilli strains alone or together with a carbohydrate fraction (CF) from caprine milk on barrier integrity of a co-culture model of the small intestinal epithelium. Barrier integrity (as measured by trans epithelial electrical resistance (TEER)), was enhanced by three bacteria/CF combinations (Lactobacillus rhamnosus HN001, L. plantarum 299v, and L. casei Shirota) to a greater extent than CF or bacteria alone. Levels of occludin mRNA were increased for all treatments compared to untreated co-cultures, and L. plantarum 299v in combination with CF had increased mRNA levels of MUC4, MUC2 and MUC5AC mucins and MUC4 protein abundance. These results indicate that three out of the four probiotic bacteria tested, in combination with CF, were able to elicit a greater increase in barrier integrity of a co-culture model of the small intestinal epithelium compared to that for either component alone. This study provides additional insight into the individual or combined roles of microbe–diet interactions in the small intestine and their beneficial contribution to the intestinal barrier.

Roles and applications of probiotic Lactobacillus strains

Lactobacilli are recognized as probiotics on account of their health-promoting effects in the host. The aim of this review is to summarize current knowledge of the mechanisms of the adaption factors and main functions of lactobacilli that exert health-promoting effects in the host and to discuss important applications in animal and human health. The adaption mechanisms of lactobacilli facilitate interactions with the host and directly contribute to the beneficial nutritional, physiological, microbiological, and immunological effects in the host. Besides, the application of probiotic lactobacilli will increase our understanding of practical uses based on the roles of these organisms in immunoregulation, antipathogenic activities, and enhancement of the epithelial barrier.

Protective Effects of Lactic Acid Bacteria Against TLR4 Induced Inflammatory Response in Hepatoma HepG2 Cells Through Modulation of Toll-Like Receptor Negative Regulators of Mitogen-Activated Protein Kinase and NF-κB Signaling

The beneficial effects of probiotics in several liver diseases have been investigated in both animal and clinical models; however, the precise mechanisms responsible for their effects have not yet been elucidated. Gut transmitted endotoxins such as LPS have been shown to play critical roles in hepatic inflammation and injury. Therefore, in this study, we investigated the beneficial role of selected lactic acid bacteria (LABs) on reduction of hepatic steatosis (HS) and attenuation of LPS induced inflammatory response in vitro. Total cellular fluid (TCF) of LABs treatment reduced HS by decreasing the amount of lipid accumulation in vitro. Additionally, HepG2 cells exposed to LPS showed increased expression of exacerbated inflammatory cytokines, such as IL-6, CXCL8, CCL2, and TNF-α, but these effects were counteracted when cells were treated with TCF of LABs prior to LPS challenge. Moreover, TCF of LABs was able to modulate mRNA levels of TLR negative regulators and protein levels of p38 MAPK and p65 NF-κB transcription factors. However, these modulations were differed remarkably between both free fatty acid treated and untreated HepG2 cells. Heat-killed LABs were also indirectly suppressed THP-1 cells to produce higher level of IL-10, TLR4, and lower at genes level of TGF-β, IL-1β, and IL-6, and at protein level of TNF-α in response to LPS. Taken together, our findings indicate that selected LABs exhibit profound immunoregulatory effects on liver cells via modulation of TLR negative regulators of the MAPK and NF-κB pathways.

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.

The functionality of prebiotics as immunostimulant: Evidences from trials on terrestrial and aquatic animals

The gut immune system is, the main option for maintaining host's health, affected by numerous factors comprising dietary constituents and commensal bacteria. These dietary components that affect the intestinal immunity and considered as an alternative of antibiotics are called immunosaccharides. Fructooligosaccharide (FOS), Galactooligosaccharide (GOS), inulin, dietary carbohydrates, and xylooligosaccharide (XOS) are among the most studied prebiotics in human as well as in aquaculture. Although prebiotics and probiotics have revealed potential as treatment for numerous illnesses in both human and fish, a comprehensive understanding of the molecular mechanism behind direct and indirect effect on the intestinal immune response will help more and perhaps extra effective therapy intended for ailments. This review covers the most newly deep-rooted scientific outcomes about the direct and indirect mechanism through which these dietetic strategies can affect intestinal immunity of terrestrial and aquatic animals. Prebiotics exert an influence on gut immune system via the increase in lysozyme and phagocytic activity, macrophage activation and stimulation of monocyte-derived dendritic cells. Furthermore, these functional molecules also enhance epithelial barrier function, beneficial gut microbial population, and production of intermediate metabolites for example short chain fatty acids (SCFAs) that assist in balancing the immune system. Moreover, emphasis will be sited on the relationship among food/feed, the microbiota, and the gut immune system. In conclusion, further studies are nonetheless essential to confirm the direct effect of prebiotics on immune response.

Biological Activities of Lactose-Derived Prebiotics and Symbiotic with Probiotics on Gastrointestinal System

Lactose-derived prebiotics provide wide ranges of gastrointestinal comforts. In this review article, the probable biochemical mechanisms through which lactose-derived prebiotics offer positive gastrointestinal health are reported along with the up-to-date results of clinical investigations; this might be the first review article of its kind, to the best of our knowledge. Lactose-derived prebiotics have unique biological and functional values, and they are confirmed as ‘safe’ by the Food and Drug Administration federal agency. Medical practitioners frequently recommend them as therapeutics as a pure form or combined with dairy-based products (yoghurt, milk and infant formulas) or fruit juices. The biological activities of lactose-derived prebiotics are expressed in the presence of gut microflora, mainly probiotics (Lactobacillus spp. in the small intestine and Bifidobacterium spp. in the large intestine). Clinical investigations reveal that galacto-oligosaccharide reduces the risks of several types of diarrhea (traveler’s diarrhea, osmotic diarrhea and Clostridium difficile associated relapsing diarrhea). Lactulose and lactosucrose prevent inflammatory bowel diseases (Crohn’s disease and ulcerative colitis). Lactulose and lactitol reduce the risk of hepatic encephalopathy. Furthermore, lactulose, galacto-oligosaccharide and lactitol prevent constipation in individuals of all ages. It is expected that the present review article will receive great attention from medical practitioners and food technologists.

In Vitro and in Vivo Selection of Potentially Probiotic Lactobacilli From Nocellara del Belice Table Olives

Table olives are increasingly recognized as a vehicle as well as a source of probiotic bacteria, especially those fermented with traditional procedures based on the activity of indigenous microbial consortia, originating from local environments. In the present study, we report characterization at the species level of 49 Lactic Acid Bacteria (LAB) strains deriving from Nocellara del Belice table olives fermented with the Spanish or Castelvetrano methods, recently isolated in our previous work. Ribosomal 16S DNA analysis allowed identification of 4 Enterococcus gallinarum, 3 E. casseliflavus, 14 Leuconostoc mesenteroides, 19 Lactobacillus pentosus, 7 L. coryniformis, and 2 L. oligofermentans. The L. pentosus and L. coryniformis strains were subjected to further screening to evaluate their probiotic potential, using a combination of in vitro and in vivo approaches. The majority of them showed high survival rates under in vitro simulated gastro-intestinal conditions, and positive antimicrobial activity against Salmonella enterica serovar Typhimurium, Listeria monocytogenes and enterotoxigenic Escherichia coli (ETEC) pathogens. Evaluation of antibiotic resistance to ampicillin, tetracycline, chloramphenicol, or erythromycin was also performed for all selected strains. Three L. coryniformis strains were selected as very good performers in the initial in vitro testing screens, they were antibiotic susceptible, as well as capable of inhibiting pathogen growth in vitro. Parallel screening employing the simplified model organism Caenorhabditis elegans, fed the Lactobacillus strains as a food source, revealed that one L. pentosus and one L. coryniformis strains significantly induced prolongevity effects and protection from pathogen-mediated infection. Moreover, both strains displayed adhesion to human intestinal epithelial Caco-2 cells and were able to outcompete foodborne pathogens for cell adhesion. Overall, these results are suggestive of beneficial features for novel LAB strains, which renders them promising candidates as starters for the manufacturing of fermented table olives with probiotic added value.

Lactobacillus plantarum lipoteichoic acid inhibits biofilm formation of Streptococcus mutans

Dental caries is a biofilm-dependent oral disease and Streptococcus mutans is the known primary etiologic agent of dental caries that initiates biofilm formation on tooth surfaces. Although some Lactobacillus strains inhibit biofilm formation of oral pathogenic bacteria, the molecular mechanisms by which lactobacilli inhibit bacterial biofilm formation are not clearly understood. In this study, we demonstrated that Lactobacillus plantarum lipoteichoic acid (Lp.LTA) inhibited the biofilm formation of S. mutans on polystyrene plates, hydroxyapatite discs, and dentin slices without affecting the bacterial growth. Lp.LTA interferes with sucrose decomposition of S. mutans required for the production of exopolysaccharide, which is a main component of biofilm. Lp.LTA also attenuated the biding of fluorescein isothiocyanate-conjugated dextran to S. mutans, which is known to have a high affinity to exopolysaccharide on S. mutans. Dealanylated Lp.LTA did not inhibit biofilm formation of S. mutans implying that D-alanine moieties in the Lp.LTA structure were crucial for inhibition. Collectively, these results suggest that Lp.LTA attenuates S. mutans biofilm formation and could be used to develop effective anticaries agents.

Inhibition of EV71 by curcumin in intestinal epithelial cells

EV71 is a positive-sense single-stranded RNA virus that belongs to the Picornaviridae family. EV71 infection may cause various symptoms ranging from hand-foot-and-mouth disease to neurological pathological conditions such as aseptic meningitis, ataxia, and acute transverse myelitis. There is currently no effective treatment or vaccine available. Various compounds have been examined for their ability to restrict EV71 replication. However, most experiments have been performed in rhabdomyosarcoma or Vero cells. Since the gastrointestinal tract is the entry site for this pathogen, we anticipated that orally ingested agents may exert beneficial effects by decreasing virus replication in intestinal epithelial cells. In this study, curcumin (diferuloylmethane, C₂₁H₂₀O₆), an active ingredient of turmeric (Curcuma longa Linn) with anti-cancer properties, was investigated for its anti-enterovirus activity. We demonstrate that curcumin treatment inhibits viral translation and increases host cell viability. Curcumin does not exert its anti-EV71 effects by modulating virus attachment or virus internal ribosome entry site (IRES) activity. Furthermore, curcumin-mediated regulation of mitogen-activated protein kinase (MAPK) signaling pathways is not involved. We found that protein kinase C delta (PKCδ) plays a role in virus translation in EV71-infected intestinal epithelial cells and that curcumin treatment decreases the phosphorylation of this enzyme. In addition, we show evidence that curcumin also limits viral translation in differentiated human intestinal epithelial cells. In summary, our data demonstrate the anti-EV71 properties of curcumin, suggesting that ingestion of this phytochemical may protect against enteroviral infections.