Immunomodulating activity of Lactobacillus paracasei subsp. paracasei NTU 101 in enterohemorrhagic Escherichia coli O157H7-infected mice

Immunomodulatory Activity of Probiotics in Models of Bacterial Infections

As resistance to conventional antibiotics among bacteria continues to increase, researchers are increasingly focusing on alternative strategies for preventing and treating bacterial infections, one of which is microbiota modulation. The objective of this review is to analyze the scientific literature on the immunomodulatory effects of probiotics in bacterial infections. This is an integrative review of the literature based on systematic steps, with searches performed in the databases Medline, PubMed, Scopus, Embase, and ScienceDirect. The most prevalent bacterial genera used to evaluate infectious processes were Salmonella, Escherichia, Klebsiella, and Streptococcus. Lactobacillus was the most commonly used probiotic genus, with Lactobacillus delbrueckii subsp. bulgaricus is the most frequently used species. In most studies, prophylactic treatment with concentrations of probiotics equal to or greater than 8 log CFU/mL was chosen. However, there was considerable heterogeneity in terms of effective treatment duration, indicating that the results cannot be generalized across all studies. This review found that probiotics interact with the immune system through different mechanisms and have a positive effect on preventing different types of bacterial infections.

Impact of Selenium Nanoparticle-Enriched Lactobacilli Feeding Against Escherichia coli O157:H7 Infection of BALB/c Mice

The effectiveness of selenium nanoparticle (SeNP)-enriched Lactiplantibacillus plantarum and Lactobacillus acidophilus was studied against Shiga toxin-producing Escherichia coli O157:H7 infection on the intestinal fragments and kidney tissue of BALB/c mice. Gut microbiota-targeted bacteria and E. coli O157:H7 counts were obtained by qPCR and PCR. Histology of ileum, colon, and kidney tissues and Stx secretions were analyzed until one-week post-infection. Mice fed with SeNP Lpb. plantarum in the preinfection feeding groups have lower E. coli O157:H7 counts and lower intestinal damage than those in the infected group. The lowest mean fecal probiotic counts were in the L. acidophilus group (7.61 log 10). In pretreatment groups of SeNP L. acidophilus and L. acidophilus, the mean counts of bacteria decreased to 104 CFU/g by day 7. The lowest Stx copy number was demonstrated in SeNP Lpb. plantarum feeding groups' day 7 (P < 0.05). Feeding groups with SeNP Lpb. plantarum had significantly higher members of Lactobacilli in their fecal microbiota than the control group on day 7. It was clarified that Se-enriched Lpb. plantarum and L. acidophilus can be useful as a method of preventing STEC infections. The viability of STEC infection exposure to selenium-enriched Lactobacillus spp. was decreased more than for non-Se-enriched Lactobacillus spp.

Human cathelicidin LL-37 exerts amelioration effects against EHEC O157:H7 infection regarding inflammation, enteric dysbacteriosis, and impairment of gut barrier function

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 infection impairs intestinal barrier function, causing intestinal inflammation and enteric dysbacteriosis. The human cathelicidin LL-37 can regulate excessive inflammatory responses, barrier function, and balance the intestinal microbial community; however, little is known about its effects on inflammation, intestinal barrier function, and microbiota disorders in EHEC O157:H7-infected mice. In this study, we investigated the protective effect of LL-37 against EHEC O157:H7 infection and elucidated the underlying mechanism using a mouse model. LL-37 treatment was found to inhibit body weight loss, restore edema and destruction of the intestinal villi, and significantly reduce epithelial apoptosis (P < 0.05) in EHEC O157:H7-infected mice. Furthermore, inflammatory infiltration of macrophages and neutrophils into the jejunum and colon was significantly decreased (P < 0.05). LL-37 significantly downregulated the production of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) (P < 0.05) and upregulated the anti-inflammatory cytokine (IL-10) during EHEC O157:H7 infection. LL-37 increased the expression of tight junction proteins (ZO-1, ZO-2, claudin-1, and occludin), which are associated with intestinal barrier function, and had a positive effect on EHEC O157:H7-induced microbial disorders, particularly in terms of the inflammation-related microbiota. LL-37 also significantly decreased the E. coli load in the liver and spleen (P < 0.01) and restored the structure of the liver and kidney. Taken together, LL-37 conferred protection in a EHEC O157:H7-induced mouse model by reducing intestinal inflammation, enhancing intestinal barrier function, and restoring the balance of the intestinal microbiota, which indicates the therapeutic potential of LL-37 against pathogen infection.

AB5 Enterotoxin-Mediated Pathogenesis: Perspectives Gleaned from Shiga Toxins

Foodborne diseases affect an estimated 600 million people worldwide annually, with the majority of these illnesses caused by Norovirus, Vibrio, Listeria, Campylobacter, Salmonella, and Escherichia coli. To elicit infections in humans, bacterial pathogens express a combination of virulence factors and toxins. AB₅ toxins are an example of such toxins that can cause various clinical manifestations, including dehydration, diarrhea, kidney damage, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Treatment of most bacterial foodborne illnesses consists of fluid replacement and antibiotics. However, antibiotics are not recommended for infections caused by Shiga toxin-producing E. coli (STEC) because of the increased risk of HUS development, although there are conflicting views and results in this regard. Lack of effective treatment strategies for STEC infections pose a public health threat during outbreaks; therefore, the debate on antibiotic use for STEC infections could be further explored, along with investigations into antibiotic alternatives. The overall goal of this review is to provide a succinct summary on the mechanisms of action and the pathogenesis of AB₅ and related toxins, as expressed by bacterial foodborne pathogens, with a primary focus on Shiga toxins (Stx). The role of Stx in human STEC disease, detection methodologies, and available treatment options are also briefly discussed.

Pediococcus pentosaceus IM96 Exerts Protective Effects against Enterohemorrhagic Escherichia coli O157:H7 Infection In Vivo

Enterohemorrhagic Escherichia coli (EHEC) is a notorious and prevalent foodborne pathogen which can cause serious intestinal diseases. The antagonistic activity of probiotics against EHEC is promising, but most of the studies concerning this subject have been carried out in vitro. Specifically, the interaction between Pediococcus pentosaceus and EHEC O157:H7 in vivo has not been reported yet. In this study, we investigated the protective effect of P. pentosaceus IM96 on EHEC O157:H7-infected female mice in vivo. The results demonstrated that P. pentosaceus IM96 reduced the level of pro-inflammatory factors and increased the level of anti-inflammatory factors of EHEC O157:H7-infected mice. Furthermore, P. pentosaceus IM96 alleviated intestinal mucosal damage and increased the level of MUC-2, tight junction (TJ) proteins, and short chain fatty acids (SCFAs). The intestinal microbial community structure and the diversity and richness of the microbiota were also changed by P. pentosaceus IM96 treatment. In summary, P. pentosaceus IM96 exerted protective effects against EHEC O157:H7 via alleviating intestinal inflammation, strengthening the intestinal barrier function, and regulating intestinal microbiota, suggesting that P. pentosaceus IM96 might serve as a potential microbial agent to prevent and treat intestinal diseases caused by EHEC O157:H7 infection in the future.

Probiotic Characterization of Lactobacillus paracasei subsp. paracasei KNI9 Inhibiting Adherence of Yersinia enterocolitica on Caco-2 Cells In Vitro

The study was aimed to characterize the probiotic properties of Lactobacillus paracasei subsp. paracasei strain KNI9 and its antagonistic activity against Yersinia enterocolitica subsp. enterocolitica. The strain KNI9 was susceptible to antibiotics such as chloramphenicol, tetracycline, erythromycin, and streptomycin recommended by European food safety authority (EFSA). Strain KNI9 exhibited tolerance to simulated oro-gastrointestinal (OGT) condition, adherence to Caco-2 cells, and antimicrobial activity against intestinal enteric pathogens such as Yersinia enterocolitica subsp. enterocolitica, Shigella boydii, and Listeria monocytogenes. Furthermore, the strain KNI9 inhibited the adherence and invasiveness of Y. enterocolitica subsp. enterocolitica to Caco-2 cell line. These results indicate that the L. paracasei subsp. paracasei KNI9 could be further developed into a potential probiotic strain after appropriate in vivo studies.

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

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

Lactobacillus animalis pZL8a: a potential probiotic isolated from pig feces for further research

This study aimed to screen a potential anti-diarrheal probiotic for pigs to meet the growing demand for antibiotic alternatives in livestock. Six intestinal pathogens, Escherichia coli (O157: H7) ATCC 43888, Staphylococcus aureus ATCC 6538, Listeria monocytogenes ATCC 19115, Salmonella Typhimurium ATCC 14028, Shigella boydii ATCC 9207, and Staphylococcus haemolyticus ZSY2 were employed as indicator bacteria. Our result showed that Lactobacillus animalis pZL8a isolated from pig feces had extensive and higher antibacterial activity against indicator pathogens among 9 tested strains. In addition, valuable attributes of pZL8a such as great tolerance of low pH (3.0) and bile salts (0.3%), high-level adhesion to Caco-2 cells, and similar susceptibility to the reference strain Lactobacillus rhamnosus GG (LGG) were observed. Compared with control, pZL8a supplement significantly improved the level of immunoglobulin G (IgG), immunoglobulin M (IgM), and interleukin-2 (IL-2) in mouse serum. Therefore, L. animalis pZL8a was proposed as a potential probiotic for further research and hope to reduce or replace the application of antibiotics in animal production.

Bacillus amyloliquefaciens TL106 protects mice against enterohaemorrhagic Escherichia coli O157:H7-induced intestinal disease through improving immune response, intestinal barrier function and gut microbiota

AIMS

This study evaluated the effects of Bacillus amyloliquefaciens TL106, isolated from Tibetan pigs' faeces, on the growth performance, immune response, intestinal barrier function, morphology of jejunum, caecum and colon, and gut microbiota in the mice with enterohaemorrhagic Escherichia coli (EHEC)-induced intestinal diseases.

METHODS AND RESULTS

In all, 40 female C57BL/6J mice were randomly divided into four groups: mice fed a normal diet (Control), mice oral administration of TL106 daily (Ba), mice challenged with EHEC O157:H7 on day 15 (O157) and mice oral administration of TL106 daily and challenged with EHEC O157:H7 on day 15 (Ba+O157). The TL106 was administrated to mice for 14 days, and mice were infected with O157:H7 at day 15. We found that TL106 could prevent the weight loss caused by O157:H7 infection and alleviated the associated increase in pro-inflammatory factors (TNF-α, IL-1β, IL-6 and IL-8) and decrease in anti-inflammatory factor (IL-10) in serum and intestinal tissues of mice caused by O157:H7 infection (P < 0·05). Additionally, TL106 could prevent disruption of gut morphology caused by O157:H7 infection, and alleviate the associated decrease in expression of tight junction proteins (ZO-1, occludin and claudin-1) in jejunum and colon (P < 0·05). In caecum and colon, the alpha diversity for bacterial community analysis of Chao and ACE index in Ba+O157 group were higher than O157 group. The TL106 stabilized gut microbiota disturbed by O157:H7, including increasing Lachnospiraceae, Prevotellaceae, Muribaculaceae and Akkermansiaceae, and reducing Lactobacillaceae.

CONCLUSIONS

We indicated the B. amyloliquefaciens TL106 can effectively protect mice against EHEC O157:H7 infection by relieving inflammation, improving intestinal barrier function, mitigating permeability disruption and stabilizing the gut microbiota.

SIGNIFICANCE AND IMPACT OF THE STUDY

Bacillus amyloliquefaciens TL106 can prevent and treat intestinal disease induced by EHEC O157:H7 in mice, which may be a promising probiotic for disease prevention in animals.

Protective effects of tryptophan-catabolizing Lactobacillus plantarum KLDS 1.0386 against dextran sodium sulfate-induced colitis in mice

Tryptophan is an essential amino acid for the human body, whose intake is through the diet. Several studies support the theory that microbiota-derived tryptophan metabolite played a crucial role in maintaining the balance between gut microbiota and the mucosal immune system. Previously, we selected the Lactobacillus plantarum KLDS 1.0386 strain with high tryptophan-metabolic activity after the screening of 16 Lactobacillus strains. The current study aimed to assess the effects of L. plantarum KLDS 1.0386 combination with tryptophan in improving ulcerative colitis (UC) induced by dextran sodium sulfate (DSS) and the potential mechanisms involved. Our results showed that L. plantarum KLDS 1.0386 combined with tryptophan (LAB + Trp) decreased DAI score, MPO level, and pro-inflammatory cytokine (TNF-α, IL-1β, and IL-6) concentration. It also increased anti-inflammatory cytokine (IL-10) production, tight junction proteins (claudin-1, occludin, and ZO-1), and mucin (MUC1 and MUC2) mRNA expressions. The level of indole-3-acetic acid (IAA), an important tryptophan metabolite in the liver, serum, and colon, was elevated after LAB + Trp treatment, which further upregulated aryl hydrocarbon receptor (AHR) mRNA expression to activate the IL-22/STAT3 signaling pathway. Moreover, the supplementation with LAB + Trp modulated gut microbiota composition. The present study provided novel insights that can be used to reduce the number of UC patients by employing a method utilizing tryptophan-catabolizing Lactobacillus strains.

Effects of Vigiis 101-LAB on a healthy population's gut microflora, peristalsis, immunity, and anti-oxidative capacity: A randomized, double-blind, placebo-controlled clinical study

Vigiis 101-LAB capsules are produced from the fermentation of Lactobacillus paracasei subsp. paracasei NTU 101. We tested effects of Vigiis 101-LAB capsules I or II (5 or 10 billion CFU/day, respectively) on gut microflora in clinical trial I, and on peristalsis, immunity, and anti-oxidative capacity in clinical trial II, during a 4-week randomized, double-blind, placebo-controlled, adaptive-design study. In trial I, 36 subjects were divided into capsule I and placebo groups. After 4 weeks, Bifidobacterium spp. and Lactobacillus spp. counts were significantly higher in the feces of treatment subjects, with increases of 4.01- and 4.25-fold, respectively. In trial II, 52 subjects were divided into capsule II and placebo groups. After 4 weeks, the treatment group was found to have improved motility, decreased food transit time, and significantly increased immunoglobulin G, immunoglobulin M, and antioxidant activity. Thus, daily administration of Vigiis 101 capsule II can improve peristalsis, immunity, and anti-oxidative capacity.

Lactobacillus paracasei-derived extracellular vesicles attenuate the intestinal inflammatory response by augmenting the endoplasmic reticulum stress pathway

Lactobacillus paracasei is a major probiotic and is well known for its anti-inflammatory properties. Thus, we investigated the effects of L. paracasei-derived extracellular vesicles (LpEVs) on LPS-induced inflammation in HT29 human colorectal cancer cells and dextran sulfate sodium (DSS)-induced colitis in C57BL/6 mice. ER stress inhibitors (salubrinal or 4-PBA) or CHOP siRNA were utilized to investigate the relationship between LpEV-induced endoplasmic reticulum (ER) stress and the inhibitory effect of LpEVs against LPS-induced inflammation. DSS (2%) was administered to male C57BL/6 mice to induce inflammatory bowel disease, and disease activity was measured by determining colon length, disease activity index, and survival ratio. In in vitro experiments, LpEVs reduced the expression of the LPS-induced pro-inflammatory cytokines IL-1α, IL-1β, IL-2, and TNFα and increased the expression of the anti-inflammatory cytokines IL-10 and TGFβ. LpEVs reduced LPS-induced inflammation in HT29 cells and decreased the activation of inflammation-associated proteins, such as COX-2, iNOS and NFκB, as well as nitric oxide. In in vivo mouse experiments, the oral administration of LpEVs also protected against DSS-induced colitis by reducing weight loss, maintaining colon length, and decreasing the disease activity index (DAI). In addition, LpEVs induced the expression of endoplasmic reticulum (ER) stress-associated proteins, while the inhibition of these proteins blocked the anti-inflammatory effects of LpEVs in LPS-treated HT29 cells, restoring the pro-inflammatory effects of LPS. This study found that LpEVs attenuate LPS-induced inflammation in the intestine through ER stress activation. Our results suggest that LpEVs have a significant effect in maintaining colorectal homeostasis in inflammation-mediated pathogenesis.

Tiny vesicles released by a bacterial species found in the human gut can reduce symptoms of inflammatory bowel disease (IBD) and prevent disease progression. People with IBD have a decreased abundance of Lactobacilli bacteria in their gut, creating an imbalance that perpetuates the disease. Replenishment of this bacteria may become a valuable therapy. Chang Mo Moon at Ewha Womans University, Yoon-Keun Kim at MD Healthcare, both in Seoul, South Korea, and co-workers demonstrated how extracellular vesicles (EVs) released by Lactobacilli paracasei can actively prevent bowel inflammation. These EVs contain a mixture of proteins, nucleic acids and other biomolecules. The team administered EV to cultured human colorectal cancer cells and to mice with induced colitis. The EVs decreased pro-inflammatory protein activity and boosted levels of protective cellular membrane proteins via augmenting ER stress pathway.

Dehydroepiandrosterone alleviates E. Coli O157:H7-induced inflammation by preventing the activation of p38 MAPK and NF-κB pathways in mice peritoneal macrophages

As an important metabolite in cholesterol metabolism, dehydroepiandrosterone (DHEA) can modulate the immune function in animals and humans, but the underlying mechanism is still unclear. The present study investigated the effect and mechanism of DHEA's anti-inflammatory action in primary mice peritoneal macrophages infected with E. coli O157:H7. The finding showed that DHEA improved the phagocytic ability in E. coli O157:H7-infected macrophages. DHEA inhibited the cytokines (including tumor necrosis factor-α, interleukin-1β and interleukin-6) secretion in E. coli O157:H7-infected macrophages. The inducible nitric oxide synthase and cyclooxygenase-2 protein level were significantly decreased in E. coli O157:H7-infected macrophages treated with DHEA. In addition, DHEA markedly decreased the phospho (p)-p38 MAPK protein level in E. coli O157:H7-infected macrophages. Furthermore, DHEA prevented the nuclear translocation of NF-κB by decreasing of p-IκB-α protein level in E. coli O157:H7-infected macrophage; and these effects of DHEA were heightened when the cells were pre-treated with p38 MAPK inhibitor SB203580. Our data indicated that DHEA alleviates the pro-inflammatory mediator production in E. coli O157:H7-infected mice peritoneal macrophages; and this beneficial action associated with it prevents the activation of p38 MAPK and NF-κB signaling pathway.

Management of STEC Gastroenteritis: Is There a Role for Probiotics?

Shiga toxin-producing Escherichia Coli (STEC) infections routinely run as a common gastroenteritis, but in many cases they may evolve towards hemolytic uremic syndrome (HUS). HUS is a rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Gut microorganisms have a fundamental impact on human physiology, because they modulate normal intestinal functions and play a pivotal role in influencing the local and systemic immune responses. Despite surveillance established in many countries and major progresses in the understanding of STEC-HUS mechanisms, no specific treatment is currently available. Targeting the gut microbiota could represent a new potential therapeutic strategy in STEC infection. In this paper, we reviewed the current knowledge about microbiota characteristics of patients with STEC infections, as well as in vitro and in vivo evidence of probiotic supplementation in managing STEC gastroenteritis and in HUS onset prevention.

Antiobesity and Uric Acid-Lowering Effect of Lactobacillus plantarum GKM3 in High-Fat-Diet-Induced Obese Rats

Objective: Obesity has become one of the world's biggest issues. This condition has a great impact on several metabolic and chronic diseases. For example, obesity is often accompanied by hyperuricemia or gout. However, few drugs are available for the treatment of obesity. The present study is to evaluate the antiobesity effect of Lactobacillus plantarum GKM3 in high-fat-diet-induced obese rats and whether taking L plantarum GKM3 can effectively reduce uric acid accumulation caused by obesity and ameliorate other harmful factors. Method: Sixty male Wistar rats were divided into five groups as follows: ( 1 ) ND group, fed normal diet; ( 2 ) HFC group, fed AIN93G-based high-fat diet containing 65% solids, 7% soybean oil, and 25% lard; ( 3 ) HFL group, fed AIN93G-based high-fat diet supplemented with 102.7 mg/kg/d L plantarum GKM3; ( 4 ) HFM group, fed AIN93G-based high-fat diet supplemented with 205.4 mg/kg/d L plantarum GKM3; and ( 5 ) HFH group, fed AIN93G-based high-fat diet supplemented with 513.5 mg/kg/d L plantarum GKM3. After 6 weeks, the body, organ, and fat weights; food intake; blood serum levels; and adipocyte size were measured. Results: Results showed that rats fed on the high-fat diet showed more body weight, increased feed efficiency, higher fat deposition, higher total liver weight, elevated serum lipid levels, and increased adipocyte size compared with those on the normal diet. All these effects were reversed by supplementation of L plantarum GKM3. Conclusions: In conclusion, we suggest that the L plantarum GKM3 supplement may have beneficial antiobesity and uric acid-lowering effects.

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.

Anticancer and Antimigration Effects of a Combinatorial Treatment of 5-Fluorouracil and Lactobacillus paracasei subsp. paracasei NTU 101 Fermented Skim Milk Extracts on Colorectal Cancer Cells

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide. Metabolites of lactic acid bacteria (LAB) have anticancer and antimetastasis capacities. This study aimed to investigate the chemotherapeutic effects of Lactobacillus paracasei subsp. paracasei NTU 101-fermented skim milk (NTU101-FM) extracts in combination with the chemotherapeutic drug 5-fluorouracil (5-FU) in a cellular CRC model. The NTU101-FM extracts effectively reduced CRC cell viability but were not cytotoxic to colon epithelial cells. Moreover, they increased RAW 264.7 cell viability. Notably, the cell viability of CRC cells was decreased by 5-FU in combination with the NTU101-FM extracts; the combinatorial treatment inhibited cell viability significantly more than 5-FU alone ( p < 0.05). An ethanol extract of NTU101-FM effectively attenuated CT26 cell migration. In conclusion, the ethanol extract prepared from NTU101-FM has a potential application as an anticancer agent in CRC.

Pharmaceutical significance of Leuconostoc mesenteroides KS-TN11 isolated from Nile Tilapia, Oreochromis niloticus

Aquatic animals are known for their myriad of beneficial bacteria with diverse biologically active compounds. The current study was aimed to isolate and characterize potentially beneficial lactic acid bacteria from Nile Tilapia and evaluate their pharmaceutical applications. The fish samples were dissected and stomach, intestine, and gills were collected and serially diluted for the isolation of lactic acid bacteria (LAB) on BCP agar media. Identification of isolate was carried by biochemical and molecular characterization using API kit and 16S rRNA gene sequencing analysis, respectively. Further, KS-TN11 was assessed for α-glucosidase inhibitory potential using the chromogenic method. A lactic acid bacterium KS-TN11 was isolated from the stomach of Nile Tilapia and identified as Leuconostoc mesenteroides. Effect of KS-TN11 on lipid accumulation in adipocytes was done by using Oil Red O staining. The isolate showed strong antibacterial activity against a number of pathogenic bacteria in vitro. In addition, L. mesenteroides KS-TN11 KS-TN11 (50 mg/ml and 100 mg/ml) tends to inhibit adipogenesis in 3T3-L1 adipocytes and thus may have possible anti-obesity effects. Moreover, L. mesenteroides KS-TN11 exhibited substantial α–glucosidase inhibitory activities by 41.33% at 50 mg/ml and 64% at 100 mg/ml, respectively. The bacterium showed potent antibacterial activity against a number of pathogenic bacteria; in addition to alpha-glucosidase activity, and inhibition of lipid accumulation in 3T3-L1 cell line. These results reinforce KS-TN11 as a novel bacterium with an impending pharmaceutical application.

The implication of probiotics in the prevention of dental caries

The current oral health crisis, whose causes are varied and complex, necessitates timely oral evaluation and early detection and treatment of oral health problems. Dramatic changes in eating habits and lifestyles are associated with the recent decline in oral health. Probiotics are "good" bacteria that support digestion and a healthy immune system and offer various health benefits to the host. Traditionally, probiotics have been used to improve gut health; the most common uses have historically been as a treatment or prevention of gastrointestinal infections and disease. During the last decade, studies have additionally suggested the intake of probiotics for oral health purposes. Probiotic use provides an effective strategy to combat oral disease, including the development of dental caries and periodontal infection. The aim of this review is to describe the beneficial roles of probiotic bacteria in the oral cavity and the potential mechanisms by which these bacteria exert their effects on oral health.

Probiotic and enterohemorrhagic Escherichia coli: An effective strategy against a deadly enemy?

Enterohemorrhagic Escherichia coli (EHEC) are major food-borne pathogens that constitute a serious public health threat. Currently, there is no specific treatment available for EHEC infections in human creating an urgent need for the development of alternative therapeutic strategies. Among them, one of the most promising approaches is the use of probiotic microorganisms. Even if many studies have shown the antagonistic effects of probiotic bacteria or yeast on EHEC survival, virulence, adhesion on intestinal epithelium or pathogen-induced inflammatory responses, mechanisms mediating their beneficial effects remain unclear. This review describes EHEC pathogenesis and novel therapeutic strategies, with a particular emphasis on probiotics. The interests and limits of a probiotic-based approach and the way it might be incorporated into global health strategies against EHEC infections will be discussed.

Effects of Lactobacillus plantarum NCU116 on Intestine Mucosal Immunity in Immunosuppressed Mice

The effects of Lactobacillus plantarum (L. plantarum) NCU116 isolated from pickled vegetables on intestine mucosal immunity in cyclophosphamide treated mice were investigated. Animals were divided into six groups: normal group (NIM), immunosuppression group (IM), immunosuppression plus L. plantarum NCU116 groups with three different doses (NCU-H, NCU-M, and NCU-L), and plus Bifidobacterium BB12 as positive control group (BB12). Results showed that the thymus indexes of the four treatment groups were significantly higher than that of the IM group (2.02 ± 0.16) (p < 0.05) and close to the index of the NIM group (2.61 ± 0.37) at 10 days. The level of immune factor IL-2 notably increased (IM, 121 ± 9.0) (p < 0.05) and was close to 65% of NIM group's level (230 ± 10.7). The levels of other immune factors (IFN-γ, IL-10, IL-12p70, and sIgA), the gene expression levels of IL-2 and IFN-γ, and the number of IgA-secreting cells showed similar patterns (p < 0.05). However, the level of immune factor IL-4 remarkably decreased (IM, 128 ± 10.2) (p < 0.05) and was only approximately 50% of the NIM group (154 ± 18.2). The levels of other immune factors (IL-6 and IgE) and the gene expression level of IL-6 at 10 days exhibited similar changes (p < 0.05) but showed a slight recovery at 20 days, accompanied by the altered protein expression levels of T-bet and GATA-3 in the small intestine. These findings suggest that L. plantarum NCU116 enhanced the immunity of the small intestine in the immunosuppressed mice.

Antihypertensive Effect of a Combination of Uracil and Glycerol Derived from Lactobacillus plantarum Strain TWK10-Fermented Soy Milk

We previously demonstrated that angiotensin-converting enzyme (ACE) could be inhibited by soy milk that had been fermented with the Lactobacillus plantarum strain TWK10, suggesting great potential for the development of antihypertensive products. In this work, the bioactive ACE inhibitors in TWK10-fermented soy milk water extracts were isolated, and a combination of uracil and glycerol (CUG) was identified as one of the ACE inhibitors. We then examined the physiological effects of CUG treatment in short-term and long-term studies using spontaneously hypertensive rats (SHRs) as an experimental model. The results revealed that the fermented soy milk extracts and CUG decreased blood pressure by 11.97 ± 3.71 to 19.54 ± 9.54 mmHg, 8 h after oral administration, and exhibited antihypertensive effects in SHRs in a long-term study. In addition, CUG was shown to decrease blood pressure by suppressing either the renin activity or the ACE activity and, thus, decreasing the downstream vasoconstricting peptide angiotensin II and the hormone aldosterone. CUG also promoted nitric oxide production, resulting in vasodilation and further improvement to hypertension. This important finding suggests that TWK10-fermented soy milk and its functional ingredients, uracil and glycerol, exhibit antihypertensive effects via multiple pathways and provide a healthier and more natural antihypertensive functional food.

Evaluation of immunomodulatory activity of two potential probiotic Lactobacillus strains by in vivo tests

Here we evaluate the immunomodulatory function of two potential probiotic strains, Lactobacillus salivarius CICC 23174 and Lactobacillus plantarum CGMCC 1.557. Mice were fed with each Lactobacillus strain at different doses for several consecutive days. The effects of the two probiotic strains on immune organs, immune cells and immune molecules were investigated on days 10 and 20. Both Lactobacillus strains increased the spleen index, improved the spleen lymphocyte transformation rate, enhanced sIgA production and improved the number of CD11c(+) CD80(+) double-positive cells. L. plantarum CGMCC 1.557 was the more active strain in enhancing the phagocytic activity of macrophages, while, L. salivarius CICC 23174 was the more effective strain at maintaining the Th1/Th2 balance. This study suggests that these two Lactobacillus strains have beneficial effects on regulation of immune responses, which has promising implications for the development of ecological agents and functional foods.

Optimization of antimicrobial substances produced from Lactobacillus paracasei subsp. paracasei NTU 101 (DSM 28047) and Lactobacillus plantarum NTU 102 by response surface methodology

Response surface methodology (RSM) was used to study the effects of medium composition and growth conditions on antimicrobial substances produced by Lactobacillus paracasei subsp. paracasei NTU 101 and Lactobacillus plantarum NTU 102. These strains are used in the food and pharmaceutical industries because of their beneficial effects on the human gastrointestinal tract and in immune modulation. The production of antimicrobial substances was optimized by the Box-Behnken experimental design. An empirical model was developed through RSM to describe the relationship between variables (molasses, soymilk, and incubation temperature). The maximum antimicrobial activity of L. paracasei subsp. paracasei NTU 101 was 12.50 AU/mL with 18.33 g/L molasses and 14.53 g/L soymilk at a temperature of 35.00 °C, whereas in MRS (de Man, Rogosa, and Sharpe) broth, the activity was 14.00 AU/mL. Similarly, the maximum antimicrobial activity of L. plantarum NTU 102 was 15.00 AU/mL with 20.56 g/L molasses and 13.54 g/L soymilk at a temperature of 36.50 °C, whereas in MRS, the activity was 13.50 AU/mL. The antimicrobial activities visualized in response surface plots were 12.26 and 15.59 AU/mL for NTU 101 and 102, respectively. The results derived from RSM regression were close to those obtained with the experimental design treatments. These results revealed that an alternative medium could be used for large-scale commercial production of the antimicrobial substances, with potential prospects for application.

Anti-obesity effects of gut microbiota are associated with lactic acid bacteria

The prevalence of obesity is rapidly becoming endemic in industrialized countries and continues to increase in developing countries worldwide. Obesity predisposes people to an increased risk of developing metabolic syndrome. Recent studies have described an association between obesity and certain gut microbiota, suggesting that gut microbiota might play a critical role in the development of obesity. Although probiotics have many beneficial health effects in humans and animals, attention has only recently been drawn to manipulating the gut microbiota, such as lactic acid bacteria (LAB), to influence the development of obesity. In this review, we first describe the causes of obesity, including the genetic and environmental factors. We then describe the relationship between the gut microbiota and obesity, and the mechanisms by which the gut microbiota influence energy metabolism and inflammation in obesity. Lastly, we focus on the potential role of LAB in mediating the effects of the gut microbiota in the development of obesity.

Therapeutic use of a receptor mimic probiotic reduces intestinal Shiga toxin levels in a piglet model of hemolytic uremic syndrome

Background

Hemolytic uremic syndrome (HUS) is a systemic and potentially fatal complication of gastroenteritis secondary to Shiga toxin-producing enterohemorrhagic Escherichia coli (EHEC) infection characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal damage. Shiga toxin (Stx), the toxin principle in HUS, is produced locally within the gut following EHEC colonization and is disseminated via the vasculature. Clinical development of HUS currently has no effective treatment and is a leading cause of renal failure in children. Novel post-exposure therapies are currently needed for HUS; therefore, the purpose of this study was to investigate the efficacy of a Stx receptor mimic probiotic in a porcine model of HUS. Edema disease, an infection of swine caused by host adapted Shiga toxin-producing Escherichia coli (STEC) and mediated by Shiga toxin 2e (Stx2e), shares many pathogenic similarities to HUS. In this study, three-week old piglets were inoculated with STEC and 24 hours later treated twice daily with a probiotic expressing an oligosaccharide receptor mimic for Stx2e to determine if the probiotic could reduce intestinal toxin levels.

Methods

Piglets were orally inoculated with 10¹⁰ CFU of STEC strain S1191 eight days after weaning. Beginning day 1 post-inoculation, piglets were treated orally twice daily with 5 × 10¹¹ CFU of either the receptor mimic probiotic or a sham probiotic for 10 days. Intestinal Stx2e levels were assessed daily via Vero cell assay. The efficacy of the probiotic at reducing intestinal Stx2e, vascular lesions, and clinical disease was evaluated with repeated measures ANOVA and Fisher’s exact test as appropriate.

Results

The probiotic significantly reduced intestinal Stx2e, as reflected by decreased fecal toxin titers on days 3–8 post-inoculation (p < 0.01). Despite this reduction in intestinal toxin levels, however, the probiotic failed to reduce the incidence of vascular necrosis in target organs and had no effect on clinical disease.

Conclusions

The data suggest that post-exposure treatment with a Stx-binding probiotic is effective in reducing intestinal toxin burden. Future studies could target this approach for possible development of post-exposure interventions.

Lactobacilli reduce chemokine IL-8 production in response to TNF-α and Salmonella challenge of Caco-2 cells

The probiotic properties of two selected lactobacilli strains were assessed. L. salivarius and L. plantarum displayed higher hydrophobicity (48% and 54%, resp.) and coaggregation ability with four pathogens (from 7.9% to 57.5%). L. salivarius and L. plantarum had good inhibitory effects on S. aureus (38.2% and 49.5%, resp.) attachment to Caco-2 cells. Live lactobacilli strains and their conditioned media effectively inhibited IL-8 production (<14.6 pg/mL) in TNF-α-induced Caco-2 cells. Antibiotic-treated and the sonicated lactobacilli also maintained inhibitory effects (IL-8 production from 5.0 to 36.3 pg/mL); however, the heat-treated lactobacilli lost their inhibitory effects (IL-8 production from 130.2 to 161.0 pg/mL). These results suggest that both the structural components and the soluble cellular content of lactobacilli have anti-inflammatory effects. We also found that pretreatment of Caco-2 cells with lactobacilli inhibited S. typhimurium-induced IL-8 production (<27.3 pg/mL). However, lactobacilli did not inhibit IL-8 production in Caco-2 cells pretreated with S. typhimurium. These results suggest that the tested lactobacilli strains are appropriate for preventing inflammatory diseases caused by enteric pathogens but not for therapy. In short, L. salivarius and L. plantarum are potential candidates for the development of microbial ecological agents and functional foods.

Colorimetric detection of Escherichia coli O157:H7 using functionalized Au@Pt nanoparticles as peroxidase mimetics

The presence of Escherichia coli (E. coli) in food and drinking water is a chronic problem worldwide. Protecting food against bacterial contamination and rapid diagnosis of infection require simple and rapid assays for detection of bacterial pathogens, including E. coli O157:H7. Here we report a rapid and novel colorimetric method for detecting E. coli O157:H7. This colorimetric method is based on the catalytic oxidation of the peroxidase substrate 3,3,5,5-tetramethylbenzidine by hydrogen peroxide using 4-mercaptophenylboronic acid-functioned Au@Pt nanoparticles adsorbed on the surface of E. coli O157:H7. The assay showed excellent sensitivity both with the naked eye and based on absorbance measurements. The absorbance at 652 nm was proportional to the concentration of E. coli O157:H7 ranging from 7 to 6 × 10(6) cfu mL(-1) with a limit of detection of 7 cfu mL(-1). The total detection time was less than 40 min.

Bioengineered probiotics, a strategic approach to control enteric infections

Enteric infections account for high morbidity and mortality and are considered to be the fifth leading cause of death at all ages worldwide. Seventy percent of all enteric infections are foodborne. Thus significant efforts have been directed toward the detection, control and prevention of foodborne diseases. Many antimicrobials including antibiotics have been used for their control and prevention. However, probiotics offer a potential alternative intervention strategy owing to their general health beneficial properties and inhibitory effects against foodborne pathogens. Often, antimicrobial probiotic action is non-specific and non-discriminatory or may be ineffective. In such cases, bioengineered probiotics expressing foreign gene products to achieve specific function is highly desirable. In this review we summarize the strategic development of recombinant bioengineered probiotics to control enteric infections, and to examine how scientific advancements in the human microbiome and their immunomodulatory effects help develop such novel and safe bioengineered probiotics.

Assessment of the probiotic potential of a dairy product fermented by Propionibacterium freudenreichii in piglets

Dairy propionibacteria, including Propionibacterium freudenreichii , display promising probiotic properties, including immunomodulation. These properties are highly strain-dependent and rarely studied in a fermented dairy product. We screened 10 strains, grown in a newly developed fermented milk ultrafiltrate, for immunomodulatory properties in vitro. The most anti-inflammatory strain, P. freudenreichii BIA129, was further tested on piglets. P. freudenreichii -fermented product improved food intake and growth of piglets. Colonic mucosa explants of treated pigs secreted less interleukin 8 (-25%, P < 0.05) and tumor necrosis factor α (-20%, P < 0.05), either in basal conditions or after a lipopolysaccharide challenge. By contrast, the gut structure, barrier function (measured ex vivo in Ussing chambers), microbial diversity (assessed by 16S rRNA pyrosequencing), and colonic short-chain fatty acid content were unchanged, assuming maintenance of normal intestinal physiology. In conclusion, this work confirms in vivo probiotic properties of dairy propionibacteria-fermented products, which are promising for the prevention or healing of inflammatory bowel diseases.

Modern approaches in probiotics research to control foodborne pathogens

Foodborne illness is a serious public health concern. There are over 200 known microbial, chemical, and physical agents that are known to cause foodborne illness. Efforts are made for improved detection, control and prevention of foodborne pathogen in food, and pathogen associated diseases in the host. Several commonly used approaches to control foodborne pathogens include antibiotics, natural antimicrobials, bacteriophages, bacteriocins, ionizing radiations, and heat. In addition, probiotics offer a potential intervention strategy for the prevention and control of foodborne infections. This review focuses on the use of probiotics and bioengineered probiotics to control foodborne pathogens, their antimicrobial actions, and their delivery strategies. Although probiotics have been demonstrated to be effective in antagonizing foodborne pathogens, challenges exist in the characterization and elucidation of underlying molecular mechanisms of action and in the development of potential delivery strategies that could maintain the viability and functionality of the probiotic in the target organ.

Immunomodulatory and antioxidant potential of Lactobacillus exopolysaccharides

BACKGROUND

Immunomodulation by probiotic microorganisms has become a topic of increasing interest in food microbiology. Polysaccharides are broadly used in the food industry as gelling, thickening, stabilizing, or emulsifying agents. Some probiotics such as lactic acid bacteria also produce exopolysaccharides that stimulate macrophage production of cytokines. The aim of this study was to characterize the effects of exopolysaccharides of Lactobacillus paracasei subsp. paracasei NTU 101 (101EP) and Lactobacillus plantarum NTU 102 (102EP) exopolysaccharides on antioxidant activity and immunomodulation in vitro.

RESULTS

The sugar composition (including arabinose, galactose, glucose, fructose, mannose, and maltose) of 101EP and 102EP was quantified by high-performance anion-exchange chromatography. Cytokine production (including IL-6, TNF-α, and IL-1β) was induced by 101EP and 102EP in Raw 264.7 in a dose-dependent manner (5-500 µg mL(-1) ). 101EP and 102EP also demonstrated potential antioxidant properties (1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, chelation of ferrous ions, inhibition of linoleic acid peroxidation, and reducing power) in vitro.

CONCLUSION

101EP and 102EP stimulate cell proliferation and may be useful as a mild immune modulator of macrophages.

Antihypertensive effects of Lactobacillus-fermented milk orally administered to spontaneously hypertensive rats

Products fermented with lactic acid bacteria may show antihypertensive effects via substances such as angiotensin I-converting enzyme inhibitor (ACEI) and γ-aminobutyric acid (GABA). It was previously found that milk fermented with Lactobacillus paracasei subsp. paracasei NTU 101 (101FM) or Lactobacillus plantarum NTU 102 (102FM) has ACEI and GABA activities. This study aimed to investigate the antihypertensive effects of 101FM and 102FM orally administered to spontaneously hypertensive rats (SHRs). Eight hours after a single oral administration or after 8 weeks of weekly (chronic) administration, 101FM and 102FM significantly decreased systolic and diastolic blood pressures in the SHRs. Microscopic examination of aortic tissue demonstrated that 101FM and 102FM reduced the disorganization of the media layer. These findings suggest that orally administered 101FM and 102FM have antihypertensive effects, possibly via ACEI and GABA activity, in SHRs. Therefore, 101FM and 102FM may be useful ingredients in physiologically functional foods to prevent hypertension.