The mucus binding of Bifidobacterium lactis Bb12 is enhanced in the presence of Lactobacillus GG and Lact. delbrueckii subsp. bulgaricus

Insights into the Anti-Adipogenic and Anti-Inflammatory Potentialities of Probiotics against Obesity

Functional foods with probiotics are safe and effective dietary supplements to improve overweight and obesity. Thus, altering the intestinal microflora may be an effective approach for controlling or preventing obesity. This review aims to summarize the experimental method used to study probiotics and obesity, and recent advances in probiotics against obesity. In particular, we focused on studies (in vitro and in vivo) that used probiotics to treat obesity and its associated comorbidities. Several in vitro and in vivo (animal and human clinical) studies conducted with different bacterial species/strains have reported that probiotics promote anti-obesity effects by suppressing the differentiation of pre-adipocytes through immune cell activation, maintaining the Th1/Th2 cytokine balance, altering the intestinal microbiota composition, reducing the lipid profile, and regulating energy metabolism. Most studies on probiotics and obesity have shown that probiotics are responsible for a notable reduction in weight gain and body mass index. It also increases the levels of anti-inflammatory adipokines and decreases those of pro-inflammatory adipokines in the blood, which are responsible for the regulation of glucose and fatty acid breakdown. Furthermore, probiotics effectively increase insulin sensitivity and decrease systemic inflammation. Taken together, the intestinal microbiota profile found in overweight individuals can be modified by probiotic supplementation which can create a promising environment for weight loss along enhancing levels of adiponectin and decreasing leptin, tumor necrosis factor (TNF)-α, interleukin (IL)-6, monocyte chemotactic protein (MCP)-1, and transforming growth factor (TGF)-β on human health.

Viability and In Vitro Gastrointestinal Transit Tolerance of Multispecies Probiotic Combinations Incorporated into Orange Juice and Drinking Water

Little is known about how combining probiotics affects the storage survival and functional performance of individual probiotics when incorporated into non-dairy drinks. Viability of Lacticaseibacillus rhamnosus GG (LG), Limosilactobacillus reuteri ATCC 55730 (LR), Bifidobacterium animalis subsp. lactis BB-12 (Bb), and Propionibacterium jensenii 702 (PJ), either alone or in multi-species combinations included in orange juice (OJ), were assessed during storage in refrigerated conditions and compared with bottled water (BW). The tolerance of probiotics included in refrigerated OJ to simulated gastrointestinal conditions was also examined. LG and LR viabilities were significantly higher in OJ than in BW (p ≤ 0.001), while the reverse was evident for PJ. Bb maintained high viability in both drinks. LG-PJ in both drinks and Bb-PJ in BW resulted in greater viabilities among the paired combinations compared to their respective monocultures when incorporated separately (p ≤ 0.001). The viability of LG in the LG-Bb-PJ combination improved significantly in BW compared with LG alone (p ≤ 0.001). OJ did not alter bacterial tolerance to simulated gastric juice but diminished tolerance to simulated intestinal juice (SIJ). In all combinations, tolerance of LG and LR to SIJ was improved, whereas tolerance of PJ declined significantly compared with respective monocultures (p ≤ 0.001). In conclusion, probiotic storage stability and gastrointestinal transit tolerance were species-dependent and affected by carrier type and combinations. These effects should be considered when formulating probiotic products.

Positive regulation of the DLT operon by TCSR7 enhances acid tolerance of Lactococcus lactis F44

Lactococcus lactis, a lactic acid bacterium, has been widely used in the fermented dairy products. The acid tolerance of L. lactis is of great importance to food fermentation and probiotic applications. As the first barrier of bacteria, the cell wall has a protective effect on strains under many stress conditions, whereas the regulatory mechanism has rarely been reported. Here, based on the transcription analysis of 9 cell wall or membrane-related genes of L. lactis F44 under acid stress, the transcription levels of DACB, DLTD, YLBA, HRTA, WP_080613266.1 (1610), and ERFK genes were significantly increased. We constructed 9 overexpressing strains with the cell wall or membrane-related genes, respectively. It was demonstrated that the survival rates under acid stress of DACB, DLTD, and ERFK were significantly higher than that of wild-type F44. To investigate the regulatory mechanism, a DNA pull-down assay was used to identify the transcriptional regulators of these 3 genes. It was discovered that the 2-component system (TCS) transcriptional regulator TCSR7 bound to the upstream region of DLTD involved in the teichoic acid (TA) alanylation. The combination was confirmed through an electrophoretic mobility shift assay in vitro. Reverse-transcription quantitative PCR results indicated that TCSR7 upregulated the expression of DLTD gene. In addition, the transcription level of TCSR7 increased approximately 1.8-fold (log2 fold change) under acidic conditions. In summary, this study found that TCSR7 was induced by acid stress to upregulate the transcription level of the DLT operon genes, which might increase the positive charge on the cell membrane surface to increase the acid tolerance of the strain. This study lays the foundation for the regulatory mechanism of TA alanylation under acid stress.

The effects of UV, gamma- and X-ray irradiation on the growth, antibacterial activity and radio-protective of Lactobacillus rhamnosus

Ionizing radiation is widely applied in food production as preservation technology and for correction of gut microbiome of cancer patients, rescuers, astronauts etc. Lactic acid bacteria can be used with the same reason. The main goal of this study was to investigate the effect of irradiation on some activities of Lactobacillus rhamnosus MDC 9661 and its effect on survival of irradiated rats. The results indicate that both UV (during 45 min) and X-ray irradiations (with 2 Sv) decreased the CFU and the antibacterial activity of the strain. Higher than 700 Sv dose of X-ray irradiation resulted in the total inhibition of antibacterial activity with the total reduction of CFU less than 10 cells ml^-1 , while irradiated with 1000 Sv dose L. rhamnosus MDC 9661 did not lose its proteolytic activity. It was also shown that L. rhamnosus MDC 9661 was not immunogenic in the organism of the rats and cannot lead to the development of autoimmune responses. L. rhamnosus MDC 9661 demonstrated the necessary properties for probiotics and can be effectively used for the correction of the gut microbiome of all target groups. The co-aggregation of the cells is one of the mechanisms for resistance of lactic acid bacteria to irradiation.

Exogenous Polyamines Influence In Vitro Microbial Adhesion to Human Mucus According to the Age of Mucus Donor

Adhesion to intestinal mucus is the first step for microbiota colonization in early life. Polyamines are polycations with important physiological functions in both procaryotic and eucaryotic cells. However, their role in intestinal mucus adhesion is not known. The objective of the present study was to evaluate whether exogenous polyamines (putrescine, spermidine, spermine, and their combination) would alter the adhesive properties of Lacticaseibacillus rhamnosus GG (LGG), Bifidobacterium animalis subs. lactis Bb12, Cronobacter sakazakii, and Escherichia coli. Human intestinal mucus was isolated from healthy infants (0-6-month-old and 6-12-month-old) and healthy adults (25-52 years old). Spermidine significantly increased Bb12 adhesion (p < 0.05) in the mucus of infants (0-6 months) but reduced the adhesion of LGG in adult mucus (p < 0.05) with no significant effect in any of the infant groups. Spermine was more effective than polyamine combinations in reducing C. sakazakii (p < 0.05) adhesion in early infant mucus (0-6 months). The adhesion ability of E. coli remained unaffected by exogenous polyamines at any age in the concentrations tested. Our data suggest that polyamines may modulate the bacterial adhesion to mucus depending on the bacterial strain and depending at what age the mucus has been generated.

Efficacy of Single-Strain Probiotics Versus Multi-Strain Mixtures: Systematic Review of Strain and Disease Specificity

The diversity of probiotic products makes choosing an appropriate probiotic challenging. One unanswered question is whether single-strain probiotics are more effective than multi-strain mixtures. The aim of this review is to account for both disease and strain specificity to determine whether single strains or multiple strains are equivalent or more effective. This literature review of randomized controlled trials from 1973 to 2019 was used to compare the pooled efficacy of trials with a single strain versus the probiotic mixture with same matched strain within the same type of disease indication. A total of 65 RCTs were included (41 with single strains, 22 multi-strain mixtures and 2 comparing single strain to mixture arms) for eight different disease indications (N = 10,863). Only three strains (L. rhamnosus GG, L. helveticus R52 and B. lactis Bb12) had corresponding trials with matching mixtures. Use of L. rhamnosus GG only was significantly more protective for necrotizing enterocolitis compared to two mixtures also containing different strains of B. lactis. The mixture of L. rhamnosus GG and B. lactis Bb12 was significantly more effective than L. rhamnosus GG alone for the eradication of H. pylori. In most cases, single strains were equivalent to mixtures. Choice of an appropriate probiotic should be based, not on the number of strains in the product, rather based on evidence-based trials of efficacy. In most cases, multi-strain mixtures were not significantly more effective than single-strain probiotics.

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.

The Effect of Donor Human Milk Fortification on The Adhesion of Probiotics In Vitro

Preterm delivery complications are the primary cause of death among children under the age of five. Preventive strategies include the use of pasteurized donor human milk (DHM), its fortification with human milk fortifiers (protein supplements), and supplementation with probiotics. Our aim was to examine the impact of DHM and fortified DHM (FDHM) on the mucus adhesion properties of two widely used probiotics. The study covered two forms of human milk fortifier, liquid and powdered, with or without probiotics and storage at 4 °C for 24 h. To test the adhesion properties of the probiotic strains, DHM+probiotics and FDHM+probiotics were prepared and added to immobilized mucus isolated from the stool of healthy Finnish infants. The probiotic adhesion was then measured by liquid scintillation. Our results suggest that addition of liquid or powdered human milk fortifier in donor human milk had no impact on probiotic adhesion. In addition, given the increased adhesion of probiotics suspended in buffer, other matrices should be further studied. These factors need to be considered when designing future intervention strategies using probiotics in preterm infants.

Skin Care and Synbiotics for Prevention of Atopic Dermatitis or Food Allergy in Newborn Infants: A 2 × 2 Factorial, Randomized, Non-Treatment Controlled Trial

BACKGROUND

Atopic dermatitis (AD) and food allergy (FA) are common childhood diseases, which may either be interrelated or be the result of skin barrier disruption and gut mucosal dysbiosis. Although some evidence suggests the efficacy of emollients and synbiotics, there is no conclusive evidence on the use of these interventions alone or in combination.

OBJECTIVES

This study is aimed at identifying the efficacy of emollients and synbiotics in preventing AD and FA in children during the first year of life.

METHODS

The babies of mothers recruited prenatally received either an emollient, synbiotic, both or neither. The intervention was carried out from birth up to 6 months of age. The age of occurrence of AD and FA were reported in multiple questionnaires at 1, 6, and 9 months and at 1 year of age. AD was diagnosed by a pediatrician at 9 months of age.

RESULTS

A -total of 459 babies qualified for the outcome assessment at 1 year of age. Neither the emollient nor the synbiotic showed any effect on reducing the development of AD and FA at 1 year of age.

CONCLUSIONS

This study did not provide any evidence to show that emollients and synbiotics, alone or in combination are sufficient to prevent the occurrence of AD or FA in children up to 1 year of age.

The Use of Selected Bacteria and Yeasts to Control Vibrio spp. in Live Food

Vibrio species are a significant causative of mass mortality in mariculture worldwide, which can quickly accumulate in live food and transmit into the larval gut. With restrictions on the use of antibiotics in aquaculture, finding a proper solution to reduce the risk of Vibriosis is vital. This study aimed to evaluate the susceptibility of Vibrio harveyi, V. campbellii, V. anguillarum, and V. parahaemolyticus to twenty-six bacterial and yeast strains and use the beneficial ones to enrich live food (Branchiopod, Artemia franciscana, rotifer, Brachionus plicatilis and copepod, Tigriopus japonicus). Thus, a modified disk diffusion method was applied. After a susceptibility assay, the bacteria and yeast beneficial in suppressing the Vibrio species were labeled by fluorescent stain and used to measure the accumulation potential in different live foods. Also, the beneficial bacteria and yeast were used to enrich live foods, and then the count of loaded Vibrio was estimated after 5, 10, 15, and 20 hours by the serial dilution method. From the total bacteria and yeast strains that were used, Candida parapsilosis, Pseudoalteromonas flavipulchra, Lactobacillus sakei, Bacillus natto, and B. amyloliquefaciens inhibited all four Vibrio species. The results of microbial labeling showed that L. sakei in Artemia, C. parapsilosis in rotifers, and V. harveyi in copepods had the highest accumulation rate. The results of the estimation of loaded Vibrio in different live foods also showed that the use of beneficial bacteria and yeast each significantly reduced the count of Vibrio. Application of bacteria and yeast to suppress pathogenic Vibrio maybe a sustainable method for preventing this pathogen from harmfully invading aquaculture and may also aid in reducing the chances of antibiotic resistance in pathogenic Vibrio.

Development of the Caecal Microbiota in Three Broiler Breeds

The development of the caecal microbiota plays a role in the metabolism and immune competence of chickens. A detailed understanding of normal succession in the caecal microbiota can inform the use of probiotics and other interventions to optimize the caecal microbiota. The development of the microbiota in caecal mucus and lumen samples from three breeds of broiler chicken (Cobb 500, n = 36; Hubbard JA87, n = 38; and Ross 308, n = 36) was observed between 0 and 42 days post hatch. Chicks were housed in the same room of a climate-controlled, biosecure chicken housing unit. Between 0 and 14 days post hatch, chicks were kept in brooder pens ensuring a mixture of breeds in each brooder. From 22 days post hatch, chicks were removed from the brooders and kept in the same room. DNA was extracted from a pooled sample of caecal mucus and luminal contents from five birds of each breed at 0, 3, 7, 14, 21, 28, and 42 days post hatch. High-throughput Illumina sequencing was performed for the V4 hypervariable region of the 16S rRNA gene. The early caecal microbiota was characterized by poor diversity and dominance by one or two bacterial species. Early colonizers of the caecum included Bifidobacteriaceae, Lachnospiraceae, Bacteroidaceae and Burkholderiaceae with some amplicon sequence variants (ASVs) assigned to Ruminococcaceae. Later colonizers of the caecal microbiota were most apparent from 14 d.p.h and included Ruminococcaceae, Clostridiales vadin BB60 group, Christensenellaceae and Bacillaceae. The caecal microbiota continued to change until 42 d.p.h when the microbiota was characterized by a high abundance of Bacteroidaceae, Lachnospiraceae and Ruminococcaceae. The lumen microbiota was significantly different to the mucus with some ASVs assigned to Lachnospiraceae, Ruminococcaceae, Christensenellaceae and Bacillaceae showing increased abundance in the mucus. ASVs assigned to Bacteroidaceae, Lactobacillaceae and Burkholderiaceae showed a preference for the lumen. Analysis of five caecal mucus samples from each breed at 42 days post hatch showed differences in microbiota composition between Ross and Cobb as well as between Ross and Hubbard. Since performance data was not collected no functional inferences as to the significance of this finding can be made.

Effect of Cell Concentration on the Persistence in the Human Intestine of Four Probiotic Strains Administered through a Multispecies Formulation

Studies devoted to evaluating the outcome of different doses of probiotics are very limited, especially for multistrain formulations. In this context, we performed an intervention study that aimed to compare the effect of the administration of two doses (7 billion and 70 billion bacterial cells) of a multistrain probiotic formulation on the persistence of the four probiotic strains that were present in the product in the fecal samples collected from healthy subjects. The overall persistence of the probiotic strains was significantly higher for the 70 billion formulation than for the 7 billion formulation. Furthermore, probiotic strains were detected earlier and for longer for the 70 billion formulation compared to those for the 7 billion formulation. All probiotic strains were recovered alive from the 70 billion preparation, whereas recovery was not possible in a few fecal samples upon administration of the 7 billion preparation. In addition, the overall number of viable probiotic cells recovered on day 14 (i.e., the last day of consumption) was significantly higher for the 70 billion formulation than that for the 7 billion formulation. Finally, we found that the viability of the probiotic cells was stable over the course of the trial independent of volunteers' handling, demonstrating good manufacturing of the product. In conclusion, this study demonstrated that strains belonging to different taxa may coexist in the human gastrointestinal tract upon ingestion of a multispecies probiotic formulation. Moreover, this study suggests that higher doses of bacterial cells in probiotic formulations may permit a higher, earlier, and longer recovery of the probiotics in the feces of healthy adults.

Multiple-strain probiotics appear to be more effective in improving the growth performance and health status of white shrimp, Litopenaeus vannamei, than single probiotic strains

The probiotic efficiencies of the mixed probiotics containing Lactobacillus pentosus BD6, Lac. fermentum LW2, Bacillus subtilis E20, and Saccharomyces cerevisiae P13 for shrimp growth and health status improvement were better than those when using single probiotics. The probiotic mixture at a level of 10⁸ colony-forming units (cfu) (kg diet)^-1 and the diets containing BD6 and E20 at 10⁹ cfu (kg diet)^-1 significantly improved the growth and health status of shrimp, whereas the diets containing P13 or LW2 did not significantly affect the growth of shrimp. No significant difference in the carcass composition was recorded among the control and treatments. After 56 days of feeding, shrimp fed the diet containing the probiotic mixture (10⁷∼10⁹ cfu (kg diet)^-1) had higher survival after injection with the V. alginolyticus, but 10⁹ cfu (kg diet)^-1 of single probiotics (except for S. cerevisiae P13) had to be administered to improve shrimp survival. The better disease resistance of shrimp in groups fed the probiotic mixture might have been due to increased phenoloxidase activity, respiratory bursts, and lysozyme activity of hemocytes. Therefore, we considered that the probiotic mixture could adequately provide probiotic efficiency for white shrimp, and a diet containing 10⁸ cfu (kg diet)^-1 probiotic mixture is recommended.

Effectiveness of Multistrain Versus Single-strain Probiotics: Current Status and Recommendations for the Future

Probiotics are investigated as single-strain and multistrain products. In the market, however, there is an increasing tendency to work with multistrain probiotics, in particular, products with a high number of different strains. There are some thoughts behind this: more strains imply more chances of success; it can mean a broader spectrum of efficacy, and there is often the hope that there are at least additive and, potentially, even synergistic effects. The present review did not find convincing evidence that these assumptions are valid. There is, however, also no strong evidence that the assumptions are incorrect and/or that there is antagonistic activity between strains in a combination. We suggest that, to answer these questions, structured research is conducted. Starting with a systematic review of meta-analyses that have compared single-strain and multistrain probiotic efficacy, dedicated human studies need to be performed, comparing single-strain and multistrain probiotics to each other and placebo. In vitro and animal studies can provide indications and may help understand mechanisms. For human, animal, and in vitro studies, it is recommended to work with the simple setup of 2 single strains, a 2-strain combination, and placebo. It is also important in such research to take into consideration the doses, as a combination product will have a higher total dose.

Lactobacillus acidophilus and Clostridium butyricum ameliorate colitis in murine by strengthening the gut barrier function and decreasing inflammatory factors

Ulcerative colitis is a type of chronic inflammation present in the intestines for which the aetiology is not yet clear. The current therapies for ulcerative colitis cannot be considered to be long-term management strategies due to their significant side effects. Therefore, it is essential to identify an alternative therapeutic strategy for ulcerative colitis. The present study focused on the evaluation of the anti-inflammatory activities of Lactobacillus acidophilus CGMCC 7282 and Clostridium butyricum CGMCC 7281. The roles of both single and combination of L. acidophilus CGMCC 7282 and C. butyricum CGMCC 7281 in ulcerative colitis were investigated in 2,4,6-trinitrobenzenesulfonic acid-induced acute colitis (Th1-type colitis) in Sprague-Dawley rats and oxazolone-induced chronic colitis (Th2-type colitis) in BALB/c mice. The in vivo studies showed that the administration of L. acidophilus CGMCC 7282, C. butyricum CGMCC 7281 and L. acidophilus CGMCC 7282 plus C. butyricum CGMCC 7281 could reduce the Th1-type colitis as well as the Th2-type colitis, and the combination of the two strains exhibited the most notable effects, as indicated by the reduced mortality rates, the suppressed disease activity indices, the improved body weights, the reduced colon weight/colon length and colon weight/body weight ratios, and the improved gross anatomic characteristics and histological features (ameliorations of neutrophil infiltration and ulceration in the colon). It was found that the alterations of the gut microbiome, the barrier function changing and the selected inflammation-related cytokines are observed in the ulcerative colitis rats/mice treated with L. acidophilus CGMCC 7282 and C. butyricum CGMCC 7281. The combination of L. acidophilus CGMCC 7282 plus C. butyricum CGMCC 7281 also exerted a stronger anti-inflammatory effect than either of the single strains alone in vitro. These findings provide evidence that the administration of L. acidophilus CGMCC 7282 plus C. butyricum CGMCC 7281 may be a promising therapy for ulcerative colitis.

Maternal supplementation alone with Lactobacillus rhamnosus HN001 during pregnancy and breastfeeding does not reduce infant eczema

BACKGROUND

In a randomized placebo-controlled trial, we previously found that the probiotic Lactobacillus rhamnosus HN001 (HN001) taken by mothers from 35 weeks of gestation until 6 months post-partum if breastfeeding and their child from birth to age 2 years halved the risk of eczema during the first 2 years of life. We aimed to test whether maternal supplementation alone is sufficient to reduce eczema and compare this to our previous study when both the mother and their child were supplemented.

METHODS

In this 2-centre, parallel double-blind, randomized placebo-controlled trial, the same probiotic as in our previous study (HN001, 6 × 10⁹ colony-forming units) was taken daily by mothers from 14-16 weeks of gestation till 6 months post-partum if breastfeeding, but was not given directly to the child. Women were recruited from the same study population as the first study, where they or their partner had a history of treated asthma, eczema or hay fever.

RESULTS

Women were randomized to HN001 (N = 212) or placebo (N = 211). Maternal-only HN001 supplementation did not significantly reduce the prevalence of eczema, SCORAD ≥ 10, wheeze or atopic sensitization in the infant by 12 months. This contrasts with the mother and child intervention study, where HN001 was associated with reductions in eczema (hazard ratio (HR): 0.39, 95% CI 0.19-0.79, P = .009) and SCORAD (HR = 0.61, 95% 0.37-1.02). However, differences in the HN001 effect between studies were not significant. HN001 could not be detected in breastmilk from supplemented mothers, and breastmilk TGF-β/IgA profiles were unchanged.

CONCLUSION

Maternal probiotic supplementation without infant supplementation may not be effective for preventing infant eczema.

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

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

Some current applications, limitations and future perspectives of lactic acid bacteria as probiotics

Several mechanism and non-mechanism-based studies supporting the claim that lactic acid bacteria (LAB) strains confer health benefits and play immune-modulatory roles were examined in this review. Probiotic applications of LAB on global burdens such as obesity and type-2 diabetes were discussed as well as the use of yoghurt and ice cream as important vehicles to convey several beneficial LAB strains. Probiotic and symbiotic dairy products may be used in the nearest future to treat a variety of health disorders. Current studies suggest that lactic acid bacteria possess anti-obesity and anti-diabetic propensities on their hosts and thus can play a crucial role in human health care. Research in the rheological and physicochemical properties of ice cream as well as its applications are also on the increase. These applications face certain hurdles including technological (for less developed countries), consumer acceptability of new functional foods may be influenced by culture, ethics or religion. There is need for more studies on the genetic basis for probiotic properties which will give further understanding regarding novel manipulation skills and applicability in nutrition and health sectors. More studies confirming the direct effects of probiotic LABs in lowering the spread of food-borne and other pathogens are also anticipated.

Mismatch between Probiotic Benefits in Trials versus Food Products

Probiotic food products contain a variety of different bacterial strains and may offer different health effects. The objective was to document the prevalence and dosage of probiotic strains in the Canadian food supply and to review the literature investigating these strains in order to understand what health benefits these products may offer. The Food Label Information Program was used to identify probiotic-containing products in the food supply. PubMed, Web of Science, and Embase were searched for randomized controlled trials that tested the health effects of these strains in humans. There were six probiotic strains/strain combinations identified in the food supply. Thirty-one studies investigated these strains and found that they are associated with decreased diarrhea and constipation, improved digestive symptoms, glycemic control, antioxidant status, blood lipids, oral health, and infant breastfeeding outcomes, as well as enhanced immunity and support for Helicobacter pylori eradication. There were a limited number of studies investigating these strains. Many studies were funded by the food industry and tested dosages that were up to twenty-five times the dosage found in most food products. Probiotic food products could have health benefits not currently reported on their labels. However, many dosages are too low to provide the benefits demonstrated in clinical trials. Further research is needed to enable more effective use of these functional foods.

Antagonistic Activity of Lactobacillus reuteri Strains on the Adhesion Characteristics of Selected Pathogens

Adhesion ability of probiotics is the key factor that decides their colonization in the gastrointestinal tract and potential to inhibit pathogens. Therefore, adhesion ability can be considered as a key determinant for probiotic efficacy. Presents study documents the antagonistic activity of viable/untreated, Lithium chloride (LiCl) treated or heat-killed forms of eight probiotic Lactobacillus reuteri strains on the adhesion characteristics of selected pathogens. All strains investigated were able to adhere to Caco-2 cells. L. reuteri strains tested were able to inhibit and displace (P < 0.05) the adhesion of Escherichia coli ATCC25922, Salmonella typhi NCDC113, Listeria monocytogenes ATCC53135, and Enterococcus faecalis NCDC115. The probiotic strain L. reuteri LR6 showed the strongest adhesion and pathogen inhibition ability among the eight L. reuteri strains tested. In addition, the abilities to inhibit and to displace adhered pathogens depended on both the probiotic and the pathogen strains tested suggesting the involvement of various mechanisms. The adhesion and antagonistic potential of the probiotic strains were significantly decreased upon exposure to 5 M LiCl, showing that surface molecules, proteinaceous in nature, are involved. The heat-killed forms of the probiotic L. reuteri strains also inhibited the attachment of selected pathogens to Caco-2 cells. In conclusion, in vitro assays showed that L. reuteri strains, as viable or heat-killed forms, are adherent to Caco-2 cells and are highly antagonistic to pathogens tested in which surface associated proteins play an important role.

Dual-coated lactic acid bacteria: an emerging innovative technology in the field of probiotics

Probiotics are living micro-organisms that do not naturally have shelf life, and normally are weakly protected against the digestive action of the GI tract. A new dual coating technology has been developed in an effort to maximize survival, that is, to be able to reach the intestine alive and in sufficient numbers to confer the beneficial health effects on the host. Dual-coating of lactic acid bacteria (LAB) is the result of fourth-generation coating technology for the protection of these bacteria at least 100-fold or greater than the uncoated LAB. This innovative technique involves a first pH-dependent protein layer that protects bacteria from gastric acid and bile salt, and a second polysaccharide matrix that protects bacteria from external factors, such as humidity, temperature and pressure, as well as the digestive action during the passage through the GI tract. Dual-coated probiotic formulation is applicable to different therapeutic areas, including irritable bowel syndrome, atopic dermatitis, acute diarrhea, chronic constipation, Helicobacter pylori eradication, and prevention of antibiotic-associated diarrhea. An updated review of the efficacy of doubly coated probiotic strains for improving bacterial survival in the intestinal tract and its consequent clinical benefits in humans is here presented.

Effects of dietary supplementation of Lactobacillus rhamnosus or/and Lactococcus lactis on the growth, gut microbiota and immune responses of red sea bream, Pagrus major

Pagrus major fingerlings (3·29 ± 0·02 g) were fed with basal diet (control) supplemented with Lactobacillus rhamnosus (LR), Lactococcus lactis (LL), and L. rhamnosus + L. lactis (LR + LL) at 10(6) cell g(-1) feed for 56 days. Feeding a mixture of LR and LL significantly increased feed utilization (FER and PER), intestine lactic acid bacteria (LAB) count, plasma total protein, alternative complement pathway (ACP), peroxidase, and mucus secretion compared with the other groups (P < 0.05). Serum lysozyme activity (LZY) significantly increased in LR + LL when compared with the control group. Additionally, fish fed the LR + LL diet showed a higher growth performance (Fn wt, WG, and SGR) and protein digestibility than the groups fed an individual LR or the control diet. Superoxide dismutase (SOD) significantly increased in LR and LR + LL groups when compared with the other groups. Moreover, the fish fed LR or LL had better improvement (P < 0.05) in growth, feed utilization, body protein and lipid contents, digestibility coefficients (dry matter, protein, and lipid), protease activity, total intestine and LAB counts, hematocrit, total plasma protein, biological antioxidant potential, ACP, serum and mucus LZY and bactericidal activities, peroxidase, SOD, and mucus secretion than the control group. Interestingly, fish fed diets with LR + LL showed significantly lower total cholesterol and triglycerides when compared with the other groups (P < 0.05). These data strongly suggest that a mixture of LR and LL probiotics may serve as a healthy immunostimulating feed additive in red sea bream aquaculture.

Probiotics for allergy prevention

Probiotics, given either as a supplement or in infant foods, have been evaluated in randomised controlled trials for allergy prevention. Here, the aim is to give an overview of the results from these primary prevention studies and to discuss current strategies. In most studies, single strains or a mixture of strains of lactic acid bacteria and bifidobacteria have been used--prenatally, postnatally or perinatally. Several meta-analyses have reported a moderate benefit of probiotics for eczema prevention, and the most consistent effect has been observed with a combined perinatal intervention in infants at high risk of allergic disease due to familial predisposition. In a recent meta-analysis, the use of multi-strain probiotics appeared to be most effective for eczema prevention. No preventive effect has been shown for other allergic manifestations. As long-term follow-up data on later onset allergic conditions (asthma and allergic rhinitis) are available only from a few of the initiated studies, reports from ongoing follow-up studies that are adequately powered to examine long-term outcomes are anticipated to provide more insight. Arguably, the differences in many aspects of study design and the use of different probiotic strains and combinations have made direct comparison difficult. To date, expert bodies do not generally recommend probiotics for allergy prevention, although the World Allergy Organization (WAO) in their recently developed guidelines suggests considering using probiotics in pregnant women, during breastfeeding and/or to the infant if at high risk of developing allergic disease (based on heredity). However, in concordance with other expert bodies, the WAO guideline panel stressed the low level of evidence and the need for adequately powered randomised controlled trials and a more standardised approach before clinical recommendations on specific strains, dosages and timing can be given.

A comparative evaluation of the efficacy of probiotic and chlorhexidine mouthrinses on clinical inflammatory parameters of gingivitis: A randomized controlled clinical study

BACKGROUND

The aim of our clinical trial was to assess and compare the antiplaque and anti-inflammatory potential of a probiotic mouthwash with 0.2% chlorhexidine and saline.

MATERIALS AND METHODS

A randomized parallel group study was designed for a period of 4 weeks on 45 systemically healthy subjects between 20 and 30 years having chronic gingivitis. The study population was divided into three groups. Group A - 15 subjects were advised experimental (probiotic) mouthwash. Group B - 15 subjects were advised positive control (chlorhexidine) mouthwash and Group C - 15 subjects into a negative control group (normal saline). Oral prophylaxis was done for all groups at baseline. After the proper oral hygiene instructions, all the three groups were instructed to rinse their mouth with 10 ml of their respective mouthrinse, undiluted for 1 min twice daily, 30 min after brushing. Clinical parameters such as plaque index (PI), gingival index (GI), and oral hygiene index simplified (OHI-S) were assessed at baseline, 2 weeks and 4 weeks, respectively.

RESULTS

At day 28, the PI, GI, and OHI-S were significantly reduced by all treatment modalities ranking probiotic and chlorhexidine is greater than saline.

CONCLUSION

The probiotic mouthrinses tested was effectively used as an adjunct to mechanical plaque control in the prevention of plaque and gingivitis. Thus, the probiotic mouthrinse has a great therapeutic potential.

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.

VSL#3 probiotics provide protection against acute intestinal ischaemia/reperfusion injury

Acute intestinal ischaemia/reperfusion injury (AII/R) is an adaptive physiologic response during critical illness, involving mesenteric vasoconstriction and hypoperfusion. Prevention of AII/R in high risk patient populations would have a significant impact on morbidity and mortality. The purpose of this study was to investigate the protective effects of VSL#3 probiotic treatment in a murine model of AII/R. Adult 129/SvEv mice were subjected to an experimental AII/R model using superior mesenteric artery occlusion. Animals were pre-treated with either three days or two weeks of VSL#3 probiotics. Local tissue injury markers were assessed by levels of myeloperoxidase and activation of nuclear factor kappa B (NFкB). Systemic and local cytokines, including interleukin (IL)-1β, IL- 10, TNFα, and interferon gamma were measured by ELISA and multiplex fluorescent detection. VSL#3 probiotics reduced local tissue inflammation and injury due to AII/R. A two-week course of VSL#3 was more effective than a shorter three-day course. The reduction in local inflammation from the two-week course of VSL#3 is correlated to a significant reduction in levels of active IL-1β, and tissue levels of myeloperoxidase. Levels of active NFкB were significantly elevated in the vehicle-fed AII/R mice, corroborating with tissue inflammation, which were attenuated by VSL#3 administrations. VSL#3 did not cause any systemic inflammation or lung injury. VSL#3 probiotics are effective in reducing local tissue injury from AII/R by down-regulating pro-inflammatory mediators and immune cell recruitment. This study highlights a potential role for VSL#3 in management of patients at high risk for AII/R.

Maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of eczema in the infant

BACKGROUND

Probiotics have shown promising potential in reducing the risk of eczema in infants. Optimal probiotic intervention regimen remains to be determined.

OBJECTIVE

We investigated whether maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of developing eczema in high-risk infants.

METHODS

This was a parallel, double-blind placebo-controlled trial of 241 mother-infant pairs. Mothers with allergic disease and atopic sensitization were randomly assigned to receive (1) Lactobacillus rhamnosus LPR and Bifidobacterium longum BL999 (LPR+BL999), (2) L paracasei ST11 and B longum BL999 (ST11+BL999), or (3) placebo, beginning 2 months before delivery and during the first 2 months of breast-feeding. The infants were followed until the age of 24 months. Skin prick tests were performed at the ages of 6, 12, and 24 months.

RESULTS

Altogether 205 infants completed the follow-up and were included in the analyses. The risk of developing eczema during the first 24 months of life was significantly reduced in infants of mothers receiving LPR+BL999 (odds ratio [OR], 0.17; 95% CI, 0.08-0.35; P < .001) and ST11+BL999 (OR, 0.16; 95% CI, 0.08-0.35; P < .001). The respective ORs for chronically persistent eczema were 0.30 (95% CI, 0.12-0.80; P = .016) and 0.17 (95% CI, 0.05-0.56; P = .003). Probiotics had no effect on the risk of atopic sensitization in the infants. No adverse effects were related to the use of probiotics.

CONCLUSION

Prevention regimen with specific probiotics administered to the pregnant and breast-feeding mother, that is, prenatally and postnatally, is safe and effective in reducing the risk of eczema in infants with allergic mothers positive for skin prick test.

Evaluation of strain-specific primers for identification of Lactobacillus rhamnosus GG

Lactobacillus rhamnosus strain GG (ATCC 53103) is one of the most widely studied and commercialized probiotic strains, and thus strain-specific identification for the strain is highly valuable. In this study, two published PCR-based identification methods for strain GG, a transposase gene-targeting system and a phage-related gene-targeting system, were evaluated. The former produced amplicons from eight of the 41 strains tested and the phage-related system from five of the tested strains, including the strain GG. Fingerprinting analysis indicated that the strains LMG 18025, LMG 18030, and LMG 18038, which had an amplicon by the former system but none by the latter, were genetically distinguishable from L. rhamnosus GG at strain level. Strains LMG 23320, LMG 23325, LMG 23534, and LMG 25859 showed profiles very similar to that of the strain GG, suggesting that these strains might be identical to GG or derivative strains of it. The results here indicated that the phage-related gene-targeting system is a good tool for accurate identification of L. rhamnosus GG. This system would be able to detect both the original L. rhamnosus GG and its derivative strains.

Lactobacillus reuteri protects epidermal keratinocytes from Staphylococcus aureus-induced cell death by competitive exclusion

Recent studies have suggested that the topical application of probiotic bacteria can improve skin health or combat disease. We have utilized a primary human keratinocyte culture model to investigate whether probiotic bacteria can inhibit Staphylococcus aureus infection. Evaluation of the candidate probiotics Lactobacillus reuteri ATCC 55730, Lactobacillus rhamnosus AC413, and Lactobacillus salivarius UCC118 demonstrated that both L. reuteri and L. rhamnosus, but not L. salivarius, reduced S. aureus-induced keratinocyte cell death in both undifferentiated and differentiated keratinocytes. Keratinocyte survival was significantly higher if the probiotic was applied prior to (P < 0.01) or simultaneously with (P < 0.01) infection with S. aureus but not when added after infection had commenced (P > 0.05). The protective effect of L. reuteri was not dependent on the elaboration of inhibitory substances such as lactic acid. L. reuteri inhibited adherence of S. aureus to keratinocytes by competitive exclusion (P = 0.026). L. salivarius UCC118, however, did not inhibit S. aureus from adhering to keratinocytes (P > 0.05) and did not protect keratinocyte viability. S. aureus utilizes the α5β1 integrin to adhere to keratinocytes, and blocking of this integrin resulted in a protective effect similar to that observed with probiotics (P = 0.03). This suggests that the protective mechanism for L. reuteri-mediated protection of keratinocytes was by competitive exclusion of the pathogen from its binding sites on the cells. Our results suggest that use of a topical probiotic prophylactically could inhibit the colonization of skin by S. aureus and thus aid in the prevention of infection.

Antagonistic activities of lactobacilli against Helicobacter pylori growth and infection in human gastric epithelial cells

Lactobacilli have positive effects on bowel microflora and health in humans and animals. In this study, the antagonistic activities of Lactobacillus gasseri Chen, and L. plantarum 18 were assessed by agar plate diffusion assay and tests that determined the growth and urease activity of Helicobacter pylori cocultured with lactobacilli and the adherence of H. pylori to human gastric epithelial cells in the presence of lactobacilli. The results showed that the 2 Lactobacillus strains had significant anti-H.pylori activity, and this activity may be contributed by the cell-free supernatants (CFS) of lactobacilli and live Lactobacillus strains in vitro. The antagonistic activity of the CFS against H. pylori depended on the pH and the presence of metabolites, such as organic acids and proteases. Our results also indicated that 2 Lactobacillus strains could inhibit H. pylori adherence human gastric epithelial cells.

PRACTICAL APPLICATION

Helicobacter pylori causes chronic gastritis, peptic ulcer disease, and gastric cancer, and it infects about 50% of the world's population. Lactobacilli have been reported to have an inhibitory effect on H. pylori and can be used as probiotic to manufacture dairy products preventing H. pylori infection.

The relative efficacy of different strain combinations of lactic acid bacteria in the reduction of populations of Salmonella enterica Typhimurium in the livers and spleens of mice

Multispecies probiotics have been reported to be more effective than monostrain probiotics in health promoting for the host. In this study, 12 lactic acid bacteria (LAB) strains were selected based on the level of induction of tumor necrosis factor (TNF)-α in RAW 264.7 macrophage cells. Their adherence to Caco-2 cells and inhibitory effects on Salmonella invasion of Caco-2 cells were compared. Strains with different probiotic properties were then combined and BALB/c mice were fed with LAB strains for 63 days; then the mice were challenged with Salmonella on day 64. For Salmonella-unchallenged mice that received a multistrain combination of LAB strains that have greater TNF-α production in macrophages, greater adherence and inhibit Salmonella invasion of Caco-2 cells to a greater extent, their peritoneal macrophages had greater phagocytic activity. For Salmonella-challenged mice, a significant reduction of Salmonella cells in the livers and spleens of the mice was observed 8 days post challenge. The addition of 12% skim milk powder together with LAB strain combinations significantly enhanced the reduction of Salmonella cells in the mice livers and spleens. In conclusion, we have shown that LAB strain combinations with particular probiotic properties when fed to mice can inhibit Salmonella invasion of the liver and spleen.

Efficacy of combined or single use of Lactobacillus crispatus LT116 and L. johnsonii LT171 on broiler performance

1. The objective of this research was to investigate the efficacy of combined or single use of Lactobacillus crispatus LT116 and Lactobacillus johnsonii LT171 on broiler performance. 2. A total of 320 one-d-old male Ross broiler chicks were allocated in 4 experimental treatments for 6 weeks. The experimental treatments received a maize-soybean meal basal diet that was supplemented as follows: 'control', with no other additions; 'LJ', 1 × 10(6) CFU of L. johnsonii LT171; 'LC', 1 × 10(6) CFU of L. crispatus LT116; and 'LCJ', 0·5 × 10(6) CFU of L. johnsonii LT171 + 0·5 × 10(6) CFU of L. crispatus LT116/g of the diet. A suspension of sheep red blood cells (SRBC) was injected into the breast of 8 birds from each treatment on d 14 and 30, and the antibody titre was measured on d 20, 26, 36 and 42. 3. Body weight was improved when compared with control for broilers fed diets supplemented with LCJ. The feed conversion ratio (FCR) decreased in LC and LCJ groups compared with control. The number of coliforms in the ileum of LJ, LC and LCJ birds was lower than that from the control birds. However, only the LCJ treatment significantly decreased the number of coliforms in the caecum. The LCJ group had greater villus height in the duodenum than the LC group, and both LCJ and LC groups showed increased villus height in the duodenum and jejunum relative to the control. Antibody titre against SRBC was higher for the LCJ group than for the LJ and control groups in terms of secondary immune response (mean of 36 and 42 d). 4. This study showed, compared with the control, that the combination of Lactobacillus spp. could positively affect body weight, coliform numbers in the caecum and immune response.

Gut microbiota is not modified by Randomized, Double-blind, Placebo-controlled Trial of VSL#3 in Diarrhea-predominant Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is a common condition that negatively impacts the quality of life for many individuals. The exact etiology of this disorder is largely unknown; however, emerging studies suggest that the gut microbiota is a contributing factor. Several clinical trials show that probiotics, such as VSL#3, can have a favorable effect on IBS. This double-blind, randomized placebo-controlled study has been conducted in diarrhea-predominant IBS subjects in order to investigate the effect of VSL#3 on the fecal microbiota. The bacterial composition of the fecal microbiota was investigated using high-throughput microarray technology to detect 16S RNA. Twenty four subjects were randomized to receive VSL#3 or placebo for 8 weeks. IBS symptoms were monitored using GSRS and quality of life questionnaires. A favorable change in Satiety subscale was noted in the VSL #3 groups. However, the consumption of the probiotic did not change the gut microbiota. There were no adverse events or any safety concerns encountered during this study. To summarize, the use of VSL#3 in this pilot study was safe and showed improvement in specific GSRS-IBS scores in diarrhea-predominant IBS subjects. The gut microbiota was not affected by VSL#3 consumption suggesting that the mechanism of action is not directly linked to the microbiota.

Cellular injuries of spray-dried Lactobacillus spp. isolated from kefir and their impact on probiotic properties

The injuries caused by spray drying (SD) of three potential probiotic lactobacilli isolated from kefir grains and the impact on some probiotic properties, were evaluated. Results demonstrated that Lactobacillus plantarum 83114 and L. kefir 8321 showed a slight reduction of viability (0.11 and 0.29 log CFU/ml respectively) after SD process, and L. kefir 8348 was found to be more sensitive to the process with a reduction in viability of 0.70 log CFU/ml. Neither membrane damage, evaluated by increased sensitivity to NaCl, lysozyme, bile salt and penicillin G, nor changes in acidifying activity in MRS and milk by lactobacilli were detected after SD. L. plantarum 83114 and L. kefir 8321 after SD did not lose their capacity to adhere to intestinal cells. Nevertheless, L. kefir 8348 showed a significant loss of adhesion capacity after SD. In addition, rehydrated spray-dried L. kefir 8321 retained the ability to protect against Salmonella invasion of intestinal cells. This effect was observed when L. kefir is co-incubated with Salmonella before invasion assay. This work shows that the membrane integrity evaluated by indirect methods and some probiotic properties of lactobacilli isolated from kefir did not change significantly after SD, and these powders could be used in functional foods applications.

Persistence of probiotic strains in the gastrointestinal tract when administered as capsules, yoghurt, or cheese

Most clinical studies of probiotics use freeze-dried, powdered bacteria or bacteria packed in capsules. However, probiotics are commercially available in various food matrices, which may affect their persistence in the gastrointestinal tract. The objective of the study was to compare oral and faecal recovery during and after administration of a combination of Lactobacillus rhamnosus GG and LC705, Propionibacterium freudenreichii subsp. shermanii JS, and Bifidobacterium animalis subsp. lactis Bb12 as capsules, yoghurt, or cheese. This randomized, parallel-group, open-label trial (n=36) included a 4-week run-in, 2-week intervention, and 3-week follow-up period. Participants consumed 10(10)cfu/day of probiotic combination and provided saliva and faecal samples before, during, and after the intervention. Strain-specific real-time PCR was used to quantify the strains. L. rhamnosus GG was the only probiotic strain regularly recovered in saliva samples. During the intervention period it was recovered in the saliva of 88% of the volunteers at least once. No difference was found between the yoghurt and cheese groups. At the end of the intervention, L. rhamnosus GG and LC705 counts were high in faecal samples of all product groups (8.08 and 8.67log(10) genome copies/g, respectively). There was no matrix effect on strain quantity in faeces or the recovery time after ceasing the intervention. For P. freudenreichii subsp. shermanii JS and B. animalis subsp. lactis Bb12, a matrix effect was found at the end of the intervention (P<0.01 and P<0.001, respectively) and in the recovery time during follow-up (P<0.05 for both). Yoghurt yielded the highest faecal quantity of JS and Bb12 strains (8.01 and 9.89log(10) genome copies/g, respectively). The results showed that the administration matrix did not influence the faecal quantity of lactobacilli, but affected faecal counts of propionibacteria and bifidobacteria that were lower when consumed in cheese. Thus, the consumption of probiotics in yoghurt matrix is highly suitable for studying potential health benefits and capsules provide a comparable means of administration when the viability of the strain in the capsule product is confirmed.

Host-microbiota interactions within the fish intestinal ecosystem

Teleost fish are in direct contact with the aquatic environment, and are therefore in continual contact with a complex and dynamic microbiota, some of which may have implications for health. Mucosal surfaces represent the main sites in which environmental antigens and intestinal microbiota interact with the host. Thus, the gut-associated lymphoid tissues (GALT) must develop mechanisms to discriminate between pathogenic and commensal microorganisms. Colonization of intestinal mucosal surfaces with a normal microbiota has a positive effect on immune regulatory functions of the gut, and disturbance in these immune regulatory functions by an imbalanced microbiota may contribute to the development of diseases. Significant attention has therefore been recently focused on the role of probiotics in the induction or restoration of a disturbed microbiota to its normal beneficial composition. Given this, this article explores the fascinating relationship between the fish immune system and the bacteria that are present in its intestinal microbiota, focusing on the bacterial effect on the development of certain immune responses.

Interaction of probiotics and pathogens--benefits to human health?

The probiotic terminology has matured over the years and currently a unified definition has been formed. Lactic acid bacteria (LAB) and bifidobacteria have been reported to remove heavy metals, cyanotoxins and mycotoxins from aqueous solutions. The binding processes appear to be species and strain specific. The most efficient microbial species and strains in the removal of these compounds vary between components tested. However, it is of interest to note that most strains characterized until now do not bind positive components or nutrients in the diet. This has significant implications to future detoxification biotechnology development. In a similar manner, lactic acid bacteria and bifidobacteria interact directly with viruses and pathogens in food and water as well as toxin producing microbes and some toxins. This review updates information and aims to characterize these interactions in association. The target is to understand probiotic health effects and to relate the mechanisms and actions to future potential of specific probiotic bacteria on decontamination of foods and water, and diets. The same aim is targeted in characterizing the role of probiotics in inactivating pathogens and viruses of health importance to facilitate the establishment of novel means of disease risk reduction related health benefits.

Probiotic properties of Lactobacillus rhamnosus and Lactobacillus paracasei isolated from human faeces

BACKGROUND

The possibility of using microbes to maintain health, and to prevent or treat disease is a topic as old as microbiology. The research of novel probiotic strains is important in order to satisfy the increasing request of the market and to obtain functional products in which the probiotic cultures are more active and with better probiotic characteristics than those already present on the market.

AIM OF THE STUDY

In this study, the probiotic potential of Lactobacillus strains isolated from Italian elderly human faeces was investigated.

METHODS

The Lactobacillus strains were identified and examined for resistance to gastric acidity and bile toxicity, adhesion to HT-29 cells, antimicrobial activities, antibiotic susceptibility and plasmid profile. Survival of the strains through human intestine was examined in a 3 months human feeding trial.

RESULTS

Two strains, Lactobacillus rhamnosus IMC 501 and Lactobacillus paracasei IMC 502, tolerated well low pH and bile acids. In antimicrobial activity assays, both strains showed inhibitory properties towards selected potential harmful microorganisms, particularly against Candida albicans. The two selected strains expressed high in vitro adherence to HT-29 cells increasing this characteristic when they are used in combination and they were resistant to vamcomycin, colistin sulphate, gentamicin, oxolinic acid and kanamycin. Moreover, the two strains could be recovered from stools of volunteers after the feeding trials.

CONCLUSIONS

Lactobacillus rhamnosus IMC 501 and L. paracasei IMC 502 present favourable strain-specific properties for their utilisation as probiotics in functional foods and the high adhesion ability of the L. rhamnosus IMC 501 and L. paracasei IMC 502 used in combination, confirmed by both in vitro and in vivo study, indicate that the two bacterial strains could be used as health-promoting bacteria.

Probiotics and dietary counselling contribute to glucose regulation during and after pregnancy: a randomised controlled trial

Balanced glucose metabolism ensures optimal fetal growth with long-term health implications conferred on both mother and child. We examined whether supplementation of probiotics with dietary counselling affects glucose metabolism in normoglycaemic pregnant women. At the first trimester of pregnancy 256 women were randomised to receive nutrition counselling to modify dietary intake according to current recommendations or as controls; the dietary intervention group was further randomised to receive probiotics (Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb12; diet/probiotics) or placebo (diet/placebo) in a double-blind manner, whilst the control group received placebo (control/placebo). Blood glucose concentrations were lowest in the diet/probiotics group during pregnancy (baseline-adjusted means 4.45, 4.60 and 4.56 mmol/l in diet/probiotics, diet/placebo and control/placebo, respectively; P = 0.025) and over the 12 months' postpartum period (baseline-adjusted means 4.87, 5.01 and 5.02 mmol/l; P = 0.025). Better glucose tolerance in the diet/probiotics group was confirmed by a reduced risk of elevated glucose concentration compared with the control/placebo group (OR 0.31 (95 % CI 0.12, 0.78); P = 0.013) as well as by the lowest insulin concentration (adjusted means 7.55, 9.32 and 9.27 mU/l; P = 0.032) and homeostasis model assessment (adjusted means 1.49, 1.90 and 1.88; P = 0.028) and the highest quantitative insulin sensitivity check index (adjusted means 0.37, 0.35 and 0.35; P = 0.028) during the last trimester of pregnancy. The effects observed extended over the 12-month postpartum period. The present study demonstrated that improved blood glucose control can be achieved by dietary counselling with probiotics even in a normoglycaemic population and thus may provide potential novel means for the prophylactic and therapeutic management of glucose disorders.

Specific probiotics in reducing the risk of acute infections in infancy--a randomised, double-blind, placebo-controlled study

A randomised, double-blind, placebo-controlled study was conducted to determine whether probiotics might be effective in reducing the risk of infections in infancy. Infants requiring formula before the age of 2 months were recruited from community well-baby clinics. Infant formula supplemented with the probiotics Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb-12 or placebo was administered daily until the age of 12 months. Incidence of early infections (before the age of 7 months) and incidence of recurrent (three or more) infections during the first year of life were recorded as the main outcome measures of the study. During the first 7 months of life, seven out of thirty-two (22 %) infants receiving probiotics and twenty out of forty (50 %) infants receiving placebo experienced acute otitis media (risk ratio (RR) 0.44 (95 % CI 0.21, 0.90); P = 0.014) and antibiotics were prescribed for ten out of thirty-two (31 %) infants receiving probiotics and twenty-four out of forty (60 %) infants receiving placebo (RR 0.52 (95 % CI 0.29, 0.92); P = 0.015). During the first year of life, nine out of thirty-two (28 %) infants receiving probiotics and twenty-two out of forty (55 %) infants receiving placebo encountered recurrent respiratory infections (RR 0.51 (95 % CI 0.27, 0.95); P = 0.022). These data suggest that probiotics may offer a safe means of reducing the risk of early acute otitis media and antibiotic use and the risk of recurrent respiratory infections during the first year of life. Further clinical trials are warranted.

Implication of an outer surface lipoprotein in adhesion of Bifidobacterium bifidum to Caco-2 cells

We found that the human intestinal isolate Bifidobacterium bifidum MIMBb75 strongly adhered to Caco-2 cells. Proteinase K and lithium chloride treatments showed that proteins play a key role in MIMBb75 adhesion to Caco-2 cells. By studying the cell wall-associated proteins, we identified a surface protein, which we labeled BopA. We purified the protein chromatographically and found that it functioned as an adhesion promoter on Caco-2 cells. In silico analysis of the gene coding for this protein and globomycin experiments showed that BopA is a cysteine-anchored lipoprotein expressed as a precursor polypeptide. A database search indicated that BopA appears to function biologically as an oligopeptide/tripeptide-solute-binding protein in the ABC transport system. We discovered a protein corresponding to BopA and its gene in eight other highly adherent B. bifidum strains. Finally, we found that B. bifidum MIMBb75 and BopA affected the production of interleukin-8 in Caco-2 epithelial cells. BopA is the first protein described to date to be directly involved in the adhesion of bifidobacteria to Caco-2 cells and to show immunomodulatory activity.

Monospecies and multispecies probiotic formulations produce different systemic and local immunostimulatory effects in the gilthead seabream (Sparus aurata L.)

The effects of the oral administration of heat-inactivated Lactobacillus delbrüeckii ssp. lactis and Bacillus subtilis, individually or combined, on gilthead seabream immune responses were investigated both systemically and locally in the gut. In a first experiment, seabream (65 g) were fed for 3 weeks different diets supplemented with 1 x 10(7)CFU g(-1)Lactobacillus, 1 x 10(7)CFU g(-1)Bacillus, or 0.5 x 10(7)CFU g(-1)Lactobacillus plus 0.5 x 10(7)CFU g(-1)Bacillus. Controls were fed non-supplemented diet. Six fish per group were sampled at the end of the trial and some humoral and cellular systemic innate immune parameters were evaluated. Feeding the mixture of the two killed bacteria species significantly increased natural complement, serum peroxidase and phagocytic activities compared with controls. In a second experiment, juvenile seabream (13 g) were fed for 3 weeks the same experimental diets and total serum IgM and numbers of gut IgM(+) cells and acidophilic granulocytes were evaluated. All these parameters were significantly higher in the multispecies probiotic group compared to monospecies and control fed groups. The advantages provided by administration of killed probiotic bacteria as well as multispecies versus monospecies formulations are discussed in light of the results obtained and for their possible application in aquacultural practices.