Effects of orally administered Lactobacillus casei DN-114 001 on the composition or activities of the dominant faecal microbiota in healthy humans

Novel probiotic preparation with in vivo gluten-degrading activity and potential modulatory effects on the gut microbiota

Gluten possesses unique properties that render it only partially digestible. Consequently, it exerts detrimental effects on a part of the worldwide population who are afflicted with celiac disease (1%) or related disorders (5%), particularly due to the potential for cross-contamination even when adhering to a gluten-free diet (GFD). Finding solutions to break down gluten during digestion has a high nutritional and social impact. Here, a randomized double-blind placebo-controlled in vivo challenge investigated the gluten-degrading activity of a novel probiotic preparation comprising lactobacilli and their cytoplasmic extracts, Bacillus sp., and bacterial protease. In our clinical trial, we collected feces from 70 healthy volunteers at specific time intervals. Probiotic/placebo administration lasted 32 days, followed by 10 days of wash-out. After preliminary GFD to eliminate residual gluten from feces, increasing amounts of gluten (50 mg-10 g) were administered, each one for 4 consecutive days. Compared to placebo, the feces of volunteers fed with probiotics showed much lower amounts of residual gluten, mainly with increased intakes. Probiotics also regulate the intestinal microbial communities, improving the abundance of genera pivotal to maintaining homeostasis. Quantitative PCR confirmed that all probiotics persisted during the intervention, some also during wash-out. Probiotics promoted a fecal metabolome with potential immunomodulating activity, mainly related to derivatives of branched-chain amino acids and short-chain fatty acids.

IMPORTANCE

The untapped potential of gluten-degrading bacteria and their application in addressing the recognized limitations of gluten-related disorder management and the ongoing risk of cross-contamination even when people follow a gluten-free diet (GFD) emphasizes the significance of the work. Because gluten, a common protein found in many cereals, must be strictly avoided to stop autoimmune reactions and related health problems, celiac disease and gluten sensitivity present difficult hurdles. However, because of the hidden presence of gluten in many food products and the constant danger of cross-contamination during food preparation and processing, total avoidance is frequently challenging. Our study presents a novel probiotic preparation suitable for people suffering from gluten-related disorders during GFD and for healthy individuals because it enhances gluten digestion and promotes gut microbiota functionality.

Improved gut microbiome recovery following drug therapy is linked to abundance and replication of probiotic strains

Probiotics have been used for decades to alleviate the negative side-effects of oral antibiotics, but our mechanistic understanding on how they work is so far incomplete. Here, we performed a metagenomic analysis of the fecal microbiota in participants who underwent a 14-d Helicobacter pylori eradication therapy with or without consumption of a multi-strain probiotic intervention (L. paracasei CNCM I-1518, L. paracasei CNCM I-3689, L. rhamnosus CNCM I-3690, and four yogurt strains) in a randomized, double-blinded, controlled clinical trial. Using a strain-level analysis for detection and metagenomic determination of replication rate, ingested strains were detected and replicated transiently in fecal samples and in the gut during and following antibiotic administration. Consumption of the fermented milk product led to a significant, although modest, improvement in the recovery of microbiota composition. Stratification of participants into two groups based on the degree to which their microbiome recovered showed i) a higher fecal abundance of the probiotic L. paracasei and L. rhamnosus strains and ii) an elevated replication rate of one strain (L. paracasei CNCMI-1518) in the recovery group. Collectively, our findings show a small but measurable benefit of a fermented milk product on microbiome recovery after antibiotics, which was linked to the detection and replication of specific probiotic strains. Such functional insight can form the basis for the development of probiotic-based intervention aimed to protect gut microbiome from drug treatments.

Health effects of yogurt consumption during paediatric age: a narrative review

Yogurt is a fermented milk product characterised by a peculiar nutritional composition with live and viable cultures of bacteria. Few studies have analysed the benefits of yogurt consumption on health outcomes during paediatric age. Recent epidemiological studies evaluating the nutritional impact of yogurt have demonstrated its significant contribution to nutrients intakes among children. Thus, consuming yogurt is a strategy to achieve recommended nutrient intake and healthier dietary choices, with potential impact on obesity and cardiometabolic outcome in children. Yogurt's effects on paediatric infectious diseases, gastrointestinal diseases and atopic-related disorders are ascribed to the specific probiotic strain administered. Interestingly, the benefits of yogurt consumption are most likely due to effects mediated through the gut microbiota and the enhancement of innate and adaptive immune responses. Therefore, supplementing standard yogurt cultures with probiotic strains could be useful to promote health at different paediatric ages, although more evidence is needed regarding the strain-related effects and their interplay within the paediatric immune system.

Microbiome Modulation as a Novel Strategy to Treat and Prevent Respiratory Infections

Acute and chronic lower airway disease still represent a major cause of morbidity and mortality on a global scale. With the steady rise of multidrug-resistant respiratory pathogens, such as Pseudomonas aeruginosa and Klebsiella pneumoniae, we are rapidly approaching the advent of a post-antibiotic era. In addition, potentially detrimental novel variants of respiratory viruses continuously emerge with the most prominent recent example being severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To this end, alternative preventive and therapeutic intervention strategies will be critical to combat airway infections in the future. Chronic respiratory diseases are associated with alterations in the lung and gut microbiome, which is thought to contribute to disease progression and increased susceptibility to infection with respiratory pathogens. In this review we will focus on how modulating and harnessing the microbiome may pose a novel strategy to prevent and treat pulmonary infections as well as chronic respiratory disease.

Colonization Ability and Impact on Human Gut Microbiota of Foodborne Microbes From Traditional or Probiotic-Added Fermented Foods: A Systematic Review

A large subset of fermented foods act as vehicles of live environmental microbes, which often contribute food quality assets to the overall diet, such as health-associated microbial metabolites. Foodborne microorganisms also carry the potential to interact with the human gut microbiome via the food chain. However, scientific results describing the microbial flow connecting such different microbiomes as well as their impact on human health, are still fragmented. The aim of this systematic review is to provide a knowledge-base about the scientific literature addressing the connection between foodborne and gut microbiomes, as well as to identify gaps where more research is needed to clarify and map gut microorganisms originating from fermented foods, either traditional or added with probiotics, their possible impact on human gut microbiota composition and to which extent foodborne microbes might be able to colonize the gut environment. An additional aim was also to highlight experimental approaches and study designs which could be better standardized to improve comparative analysis of published datasets. Overall, the results presented in this systematic review suggest that a complex interplay between food and gut microbiota is indeed occurring, although the possible mechanisms for this interaction, as well as how it can impact human health, still remain a puzzling picture. Further research employing standardized and trans-disciplinary approaches aimed at understanding how fermented foods can be tailored to positively influence human gut microbiota and, in turn, host health, are therefore of pivotal importance.

Effects of a Fermented Dairy Drink Containing Lacticaseibacillus paracasei subsp. paracasei CNCM I-1518 (Lactobacillus casei CNCM I-1518) and the Standard Yogurt Cultures on the Incidence, Duration, and Severity of Common Infectious Diseases: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

There is considerable interest in the role of probiotics in immune function. The objective of this systematic review and meta-analysis was to assess the effects of the consumption of a fermented dairy drink containing Lacticaseibacillus paracasei subsp. paracasei CNCM I-1518 (the previous taxonomic nomenclature was Lactobacillus casei CNCM I-1518, prior to the nomenclature change in April 2020) and the standard yogurt cultures (hereinafter referred to collectively as “FDD”) on common infectious diseases (CIDs) in generally healthy children and adults. Nine literature databases were searched, and nine randomized controlled trials from eight publications were eligible for inclusion. Combined effect sizes were determined for three metrics of CID incidence, two metrics of CID duration, and one metric of CID severity. Compared to the control, the consumption of the FDD resulted in (1) a significant reduction in the odds of experiencing ≥1 CID (odds ratio (OR) (with a 95% confidence interval (CI)): 0.81 (0.66, 0.98); p = 0.029); (2) a significant reduction in mean CIDs per subject (−0.09 (−0.15, −0.04); p = 0.001); and (3) a trend towards reduced risk in cumulative CIDs (relative risk (RR): 0.91 (0.82, 1.01); p = 0.082). The consumption of the FDD had no significant effect on CID duration or severity. Based on the studies conducted thus far, these results suggest that the FDD may reduce CID incidence in the general population.

Microbiota and Lifestyle: A Special Focus on Diet

It is widely known that a good balance and healthy function for bacteria groups in the colon are necessary to maintain homeostasis and preserve health. However, the lack of consensus on what defines a healthy gut microbiota and the multitude of factors that influence human gut microbiota composition complicate the development of appropriate dietary recommendations for our gut microbiota. Furthermore, the varied response to the intake of probiotics and prebiotics observed in healthy adults suggests the existence of potential inter- and intra-individual factors, which might account for gut microbiota changes to a greater extent than diet. The changing dietary habits worldwide involving consumption of processed foods containing artificial ingredients, such as sweeteners; the coincident rise in emotional disorders; and the worsening of other lifestyle habits, such as smoking habits, drug consumption, and sleep, can together contribute to gut dysbiosis and health impairment, as well as the development of chronic diseases. This review summarizes the current literature on the effects of specific dietary ingredients (probiotics, prebiotics, alcohol, refined sugars and sweeteners, fats) in the gut microbiota of healthy adults and the potential inter- and intra-individual factors involved, as well as the influence of other potential lifestyle factors that are dramatically increasing nowadays.

Probiotics in the next-generation sequencing era

Technological developments, including massively parallel DNA sequencing, gnotobiotics, metabolomics, RNA sequencing and culturomics, have markedly propelled the field of microbiome research in recent years. These methodologies can be harnessed to improve our in-depth mechanistic understanding of basic concepts related to consumption of probiotics, including their rules of engagement with the indigenous microbiome and impacts on the human host. We have recently demonstrated that even during probiotic supplementation, resident gut bacteria in a subset of individuals resist the mucosal presence of probiotic strains, limiting their modulatory effect on the microbiome and on the host gut transcriptional landscape. Resistance is partly alleviated by antibiotics treatment, which enables probiotics to interact with the host at the gut mucosal interface, although rather than promoting reconstitution of the indigenous microbiome and of the host transcriptional profile, they inhibit these components from returning to their naïve pre-antibiotic configurations. In this commentary, we discuss our findings in the context of previous and recent works, and suggest that incorporating the state-of-the-art methods currently utilized in microbiome research into the field of probiotics may lead to improved understanding of their mechanisms of activity, as well as their efficacy and long-term safety.

Bacteriocin production and adhesion properties as mechanisms for the anti-listerial activity of Lactobacillus plantarum 423 and Enterococcus mundtii ST4SA

Probiotics play an important role in maintaining a healthy and stable intestinal microbiota, primarily by preventing infection. Probiotic lactic acid bacteria (LAB) are known to be inhibitory to many bacterial enteric pathogens, including antibiotic-resistant strains. Whilst the positive role that probiotics have on human physiology, specifically in the treatment or prevention of specific infectious diseases of the gastro-intestinal tract (GIT) is known, the precise mechanistic basis of these effects remains a major research goal. In this study, molecular evidence to underpin the protective and anti-listerial effect of Lactobacillus plantarum 423 and Enterococcus mundtii ST4SA against orally administered Listeria monocytogenes EGDe in the GIT of mice is provided. Bacteriocins plantaricin 423 and mundticin ST4SA, produced by L. plantarum 423 and E. mundtii ST4SA, respectively, inhibited the growth of L. monocytogenes in vitro and in vivo. Bacteriocin-negative mutants of L. plantarum 423 and E. mundtii ST4SA failed to exclude L. monocytogenes EGDe from the gastrointestinal tract (GIT) of mice. Furthermore, L. plantarum 423 and E. mundtii ST4SA failed to inhibit recombinant strains of L. monocytogenes EGDe in vivo that expressed the immunity proteins of the two bacteriocins. These results confirmed that bacteriocins plantaricin 423 and mundticin ST4SA acted as anti-infective mediators in vivo. Compared to wild type strains, mutants of L. plantarum 423 and E. mundtii ST4SA, in which the adhesion genes were knocked out, were less effective in the exclusion of L. monocytogenes EGDe from the GIT of mice. This work demonstrates the importance of bacteriocin and adhesion genes as probiotic anti-infective mechanisms.

Sampling Strategies for Three-Dimensional Spatial Community Structures in IBD Microbiota Research

Identifying intestinal microbiota is arguably an important task that is performed to determine the pathogenesis of inflammatory bowel diseases (IBD); thus, it is crucial to collect and analyze intestinally-associated microbiota. Analyzing a single niche to categorize individuals does not enable researchers to comprehensively study the spatial variations of the microbiota. Therefore, characterizing the spatial community structures of the inflammatory bowel disease microbiome is critical for advancing our understanding of the inflammatory landscape of IBD. However, at present there is no universally accepted consensus regarding the use of specific sampling strategies in different biogeographic locations. In this review, we discuss the spatial distribution when screening sample collections in IBD microbiota research. Here, we propose a novel model, a three-dimensional spatial community structure, which encompasses the x-, y-, and z-axis distributions; it can be used in some sampling sites, such as feces, colonoscopic biopsy, the mucus gel layer, and oral cavity. On the basis of this spatial model, this article also summarizes various sampling and processing strategies prior to and after DNA extraction and recommends guidelines for practical application in future research.

Use of probiotics to correct dysbiosis of normal microbiota following disease or disruptive events: a systematic review

OBJECTIVE

To assess the evidence for the claim probiotics can correct dysbiosis of the normal microbiota resulting from disease or disruptive events.

SETTING

Systematic review of published clinical trials of patients receiving a probiotic intervention for the prevention or treatment of various diseases.

DATA SOURCES

Sources searched (1985-2013): PubMed, EMBASE, Cochrane Database of Systematic Reviews, CINAHL, AMED and ISI Web of Science. Three on-line clinical trial registries were searched: Cochrane Central Register of Controlled trials, MetaRegister of Controlled Trials and National Institutes of Health.

REVIEW METHODS

Included studies were randomised clinical trials of probiotic interventions having microbiological assays. Studies were evaluated following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for specific probiotic strains. A standard data extraction form was used to collect the raw data.

OUTCOME MEASURES

The primary outcome is the degree of microbiota correction by specific probiotic strains. Secondary outcome was the association between the degree of dysbiosis correction and clinical efficacy.

RESULTS

The review of the literature found three distinct study designs: model A (restoration) assayed patients enrolled with a healthy, undisturbed microbiota and then assayed postdisruptive event and probiotic therapy; model B (alteration) assayed patients with pre-existing disrupted microbiota and then postprobiotic therapy; model C (no dysbiosis) assayed volunteers with no disruptive event prebiotic and postprobiotic. From a total of 63 trials, 83% of the probiotic products using model A restored the microbiota, 56% using model B improved the microbiota and only 21% using model C had any effect on microbiota. Clinical efficacy was more commonly associated with strains capable of restoration of the normal microbiota.

CONCLUSIONS

The ability to assess the degree of dysbiosis improvement is dependent on the enrolled population and the timing of microbiological assays. The functional claim for correcting dysbiosis is poorly supported for most probiotic strains and requires further research.

TRIAL REGISTRATION NUMBER

PROSPERO (CRD42014007224).

Fermented dairy products modulate Citrobacter rodentium-induced colonic hyperplasia

We evaluated the protective effects of fermented dairy products (FDPs) in an infection model, using the mouse pathogen Citrobacter rodentium (CR). Treatment of mice with FDP formulas A, B, and C or a control product did not affect CR colonization, organ specificity, or attaching and effacing lesion formation. Fermented dairy product A (FDP-A), but neither the supernatant from FDP-A nor β-irradiated (IR) FDP-A, caused a significant reduction in colonic crypt hyperplasia and CR-associated pathology. Profiling the gut microbiota revealed that IR-FDP-A promoted higher levels of phylotypes belonging to Alcaligenaceae and a decrease in Lachnospiraceae (Ruminococcus) during CR infection. Conversely, FDP-A prevented a decrease in Ruminococcus and increased Turicibacteraceae (Turicibacter). Importantly, loss of Ruminococcus and Turicibacter has been associated with susceptibility to dextran sodium sulfate-induced colitis. Our results demonstrate that viable bacteria in FDP-A reduced CR-induced colonic crypt hyperplasia and prevented the loss of key bacterial genera that may contribute to disease pathology.

Dual functions of Lactobacillus acidophilus NCFM as protection against rotavirus diarrhea

OBJECTIVE

The aim of the study was to examine the dose effects of Lactobacillus acidophilus (LA) NCFM strain on rotavirus-specific antibody and B-cell responses in gnotobiotic pigs vaccinated with an oral attenuated human rotavirus (AttHRV).

METHODS

Pigs were inoculated with AttHRV vaccine in conjunction with high-dose LA (14 doses, total 2.2 × 10(6) colony-forming units [CFU]), intermediate-dose LA (MidLA) (9 doses, total 3.2 × 10(9) CFU), low-dose LA (LoLA) (5 doses, total 2.1 × 10(6) CFU), or without LA feeding. Protection against rotavirus shedding and diarrhea was assessed upon challenge with a virulent HRV. Rotavirus-specific immunoglobulin A (IgA) and IgG antibodies in serum and rotavirus-specific IgA and IgG antibody-secreting cells (ASCs) and memory B cells in ileum, spleen, and blood of the pigs were measured and compared among treatment groups.

RESULTS

The MidLA, but not high-dose LA or LoLA, significantly reduced rotavirus diarrhea (MidLA-only group) and significantly improved the protection conferred by AttHRV vaccine (MidLA + AttHRV group). Associated with the increased protection, MidLA significantly enhanced rotavirus-specific antibody, ASCs, and memory B-cell responses to AttHRV vaccine. High-dose LA or LoLA did not enhance virus-specific antibody and ASC responses, and hence did not improve the vaccine efficacy.

CONCLUSIONS

These findings highlight the importance of dose selection and indicate that certain specific lactobacilli strains at the appropriate dose have the dual function of reducing rotavirus diarrhea and enhancing the immunogenicity and protective efficacy of rotavirus vaccines.

In vitro fermentation characteristics of select nondigestible oligosaccharides by infant fecal inocula

This study sought to determine the fermentation potential of human milk oligosaccharides by mixed cultures of fecal microbiota from breast-fed (BF; n = 4) and formula-fed (FF; n = 4) infants. Infant fecal inocula were incubated with galactooligosaccharide (GOS), gum arabic (GA), HP inulin (HP), 2'-fucosyllactose (2'FL), 6'-sialyllactose (6'SL), and lacto-N-neotetraose (LNnt). GOS, 2'FL, and LNnT had a lower pH than other substrates after 3 h (P < 0.05). Total short chain fatty acids were greater in FF compared to BF infants at 6 h (P = 0.03) and 12 h (P = 0.01). GOS, 2'FL, and LNnT led to more lactate than 6'SL, HP, and GA (P < 0.05). Bifidobacteria populations were greater (P = 0.02) in FF at 6 and 12 h. Overall, GOS, 2'FL, and LNnT were rapidly fermented by infant fecal inocula, 6'SL and HP had intermediate fermentability, while GA had little fermentation. Inocula from FF infants fermented substrates more rapidly than inocula from BF infants, which should be accounted for when evaluating substrate fermentability. These data will aid in future infant formulas to promote optimal gut health in FF infants.

The effect of probiotics on faecal microbiota and genotoxic activity of faecal water in patients with atopic dermatitis: a randomized, placebo-controlled study

BACKGROUND

Colonic microbiota is involved in the etiology of colon cancer according to several reports. Studies also indicate that the microbiota differs between atopic patients and healthy subjects.

OBJECTIVE

To evaluate whether a probiotic mix containing Lactobacillus paracasei Lpc-37, Lactobacillus acidophilus 74-2, and Bifidobacterium animalis subsp. lactis DGCC 420 can affect the microbiota and its genotoxic activity in healthy subjects and patients with atopic dermatitis (AD).

METHODS

A placebo-controlled cross-over study was conducted. Fifteen healthy adults and 15 adult AD patients consumed 2×100 ml/d of either a probiotic or a placebo drink for 8 weeks followed by a wash out period of 2 weeks before crossing the intervention. Faecal water was isolated from stool samples collected at the end of each period. HT29c19a cells incubated with faecal water were measured for DNA damage using single-cell gel electrophoresis ("comet assay"). Bacterial species were determined by qPCR and concentrations of short-chain fatty acids were measured by means of gas chromatography.

RESULTS

Probiotic supplementation resulted in a significant increase in lactobacilli, whereas numbers of Bifidobacteria and Bacteroidetes remained unchanged. Clostridium perfringens cluster I-II was significantly reduced in healthy subjects. Genotoxic potential (expressed as tail intensity) of faecal water, was not affected. However, tail intensity decreased significantly in the probiotic period compared to placebo (23.5 vs. 16.7%) in AD patients. Although faecal concentrations of short-chain fatty acids were not affected, faecal pH was significantly reduced (7.0 vs. 6.6) in AD patients after probiotics.

CONCLUSION

The results indicate that probiotics lower the genotoxic potential of faecal water in AD patients. The faecal C. perfringens cluster I-II levels remained unaffected suggesting either a change in their activity, or the fact that other bacterial species are responsible for the reduced genotoxic activity of faecal water.

A probiotic mixture including galactooligosaccharides decreases fecal β-glucosidase activity but does not affect serum enterolactone concentration in men during a two-week intervention

A high serum concentration of enterolactone, an enterolignan produced by colonic microbiota from precursors in cereals, vegetables, and fruits, is associated with reduced risk of acute coronary events. Probiotics and prebiotics modify colonic metabolism and may affect the serum enterolactone concentration. The effects of a probiotic mixture alone and with galactooligosaccharides (GOS) on serum enterolactone concentration and fecal metabolism were investigated in 18 healthy men. Participants received 3 interventions, each for 2 wk: 1) probiotics [Lactobacillus rhamnosus strains GG (LGG) and LC705, Propionibacterium freudenreichii ssp. shermanii JS, and Bifidobacterium breve Bb99, for a total amount of 2 × 10(10) CFU/d]; 2) probiotics and GOS 3.8 g/d; 3) probiotics, GOS, and rye bread (minimum 120 g/d). Serum enterolactone and fecal dry weight, enzyme activities, pH, SCFA, lactic acid bacteria, bifidobacteria, propionibacteria, and the strains LGG and LC705 were determined. The serum enterolactone concentration (nmol/L) tended to be decreased from baseline [mean (95% CI) 18.6 (10.8-26.4)] by probiotics alone [15.2 (7.8-22.7); P = 0.095], was not significantly affected by probiotics with GOS [21.5 (13.2-29.8)], and was increased by probiotics with GOS and rye bread [24.6 (15.4-33.7); P < 0.05]. Probiotics alone did not affect fecal β-glucosidase activity and bifidobacteria, but probiotics with GOS decreased β-glucosidase activity and increased bifidobacteria compared with baseline (P < 0.05) and with probiotics alone (P < 0.01). In conclusion, this probiotic mixture with or without GOS does not significantly affect serum enterolactone concentration. Because probiotics with GOS decreased fecal β-glucosidase activity but not serum enterolactone, the reduced fecal β-glucosidase, within the range of activities measured, does not seem to limit the formation of enterolactone.

The role of oral hygiene in inflammatory bowel disease

BACKGROUND

The 'hygiene hypothesis' suggests that a reduction in the microbial exposure due to improved health measures has contributed to an immunological imbalance in the intestine and increased the incidence of autoimmune diseases such as inflammatory bowel diseases (IBD). Accordingly, we investigated associations between oral hygiene practices and IBD.

METHODS

We developed and administered a multiple choice questionnaire to evaluate oral hygiene and dental care practices of 137 subjects (83 with IBD and 54 healthy controls).

RESULTS

Of the 83 IBD cases, 31% had ulcerative colitis and 69% had Crohn's disease. For subjects with IBD, the frequency of brushing at disease onset was significantly higher than in controls (P=0.005). Also, the frequency of use of dental floss and breath freshener at disease onset was significantly higher in IBD patients (P=0.005 and<0.001, respectively). Also, patients with IBD more frequently visited their dentist at disease onset (P<0.001) and continued to visit their dentist more often (P<0.001). IBD cases had a higher frequency of dental complications such as tooth caries (P=0.007), oral ulcers (P=0.04) and dry mouth (P=0.001).

CONCLUSIONS

These findings suggest that oral hygiene practices may cause alterations in the flora of the oral mucosa, which causes imbalance in the gut microbiome (dysbiosis), and thereby contributes to the pathogenesis of IBD. Conversely, the increased frequency of dental problems in IBD patients might be due, at least in part, to alterations in oral flora or to their disease.

Consumption of a fermented dairy product containing the probiotic Lactobacillus casei DN-114001 reduces the duration of respiratory infections in the elderly in a randomised controlled trial

Common infectious diseases (CID) of the airways and the gastrointestinal tract are still a considerable cause of morbidity and mortality in elderly. The present study examined the beneficial effect of a dairy product containing the probiotic strain Lactobacillus casei DN-114 001 (fermented product) on the resistance of free-living elderly to CID. The study was multicentric, double blind and controlled, involving 1072 volunteers (median age = 76.0 years) randomised for consumption of either 200 g/d of fermented (n 537) or control (non-fermented) dairy product (n 535) for 3 months, followed by an additional 1 month's follow-up. The results showed that, when considering all CID, the fermented product significantly reduced the average duration per episode of CID (6.5 v. 8 d in control group; P = 0.008) and the cumulative duration of CID (7 v. 8 d in control group; P = 0.009). Reduction in both episode and cumulative durations was also significant for all upper respiratory tract infections (URTI; P < 0.001) and for rhinopharyngitis (P < 0.001). This was accompanied with an increase of L. casei species in stools throughout the fermented product consumption (2-3.8 x 107 equivalents of colony-forming unit/g of stools, P < 0.001). The cumulative number of CID (primary outcome) was not different between groups nor was the CID severity, fever, pathogens' occurrence, medication, immune blood parameters and quality of life. The fermented product was safe and well tolerated. In conclusion, consumption of a fermented dairy product containing the probiotic strain L. casei DN-114 001 in elderly was associated with a decreased duration of CID in comparison with the control group, especially for URTI such as rhinopharyngitis.

Lactobacillus casei downregulates commensals' inflammatory signals in Crohn's disease mucosa

BACKGROUND

The interaction of commensal bacteria with the intestinal immune system is an essential factor in the development of inflammatory bowel disease (IBD). The study of isolated commensal bacteria's effects on the mucosal immune response might be relevant for a better understanding of pathophysiological mechanisms in IBD.

METHODS

We investigated the immune responses to signals from the commensal Escherichia coli ATCC 35345 and the probiotic Lactobacillus casei DN-114 001 in Crohn's disease (CD) mucosa. Ileal specimens were obtained during surgery from CD patients. Mucosal explants were incubated with L. casei or its genomic DNA; TNF-alpha, IFN-gamma, IL-2, IL-6, IL-8, and CXCL1 were measured in the supernatant. Second, tissue expression of key proinflammatory cytokines (IL-6, TGF-beta, IL-23p19, IL-12p35, IL-17F), and chemokines (IL-8, CXCL1, CXCL2) was evaluated after incubation with L. casei or E. coli. Finally, combination experiments were carried out by incubating both strains with mucosal explants at different timepoints.

RESULTS

Live L. casei significantly decreased secretion of TNF-alpha, IFN-gamma, IL-2, IL-6, IL-8, and CXCL1 by CD mucosa, but the effect was not reproduced by L. casei DNA. Second, live L. casei downregulated expression of IL-8, IL-6, and CXCL1 and did not modify expression of IL-23p19, IL-12p35, and IL-17F. In contrast, E. coli significantly upregulated expression of all these cytokines. Interestingly, combination experiments revealed the ability of L. casei to prevent and counteract the proinflammatory effects of E. coli.

CONCLUSIONS

Live L. casei can counteract the proinflammatory effects of E. coli on CD inflamed mucosa by specific downregulation of key proinflammatory mediators.

Application of sequence-dependent electrophoresis fingerprinting in exploring biodiversity and population dynamics of human intestinal microbiota: what can be revealed?

Sequence-dependent electrophoresis (SDE) fingerprinting techniques such as denaturing gradient gel electrophoresis (DGGE) have become commonplace in the field of molecular microbial ecology. The success of the SDE technology lays in the fact that it allows visualization of the predominant members of complex microbial ecosystems independent of their culturability and without prior knowledge on the complexity and diversity of the ecosystem. Mainly using the prokaryotic 16S rRNA gene as PCR amplification target, SDE-based community fingerprinting turned into one of the leading molecular tools to unravel the diversity and population dynamics of human intestinal microbiota. The first part of this review covers the methodological concept of SDE fingerprinting and the technical hurdles for analyzing intestinal samples. Subsequently, the current state-of-the-art of DGGE and related techniques to analyze human intestinal microbiota from healthy individuals and from patients with intestinal disorders is surveyed. In addition, the applicability of SDE analysis to monitor intestinal population changes upon nutritional or therapeutic interventions is critically evaluated.

Modulation of Lactobacillus casei in ileal and fecal samples from healthy volunteers after consumption of a fermented milk containing Lactobacillus casei DN-114 001Rif

Lactobacillus casei DN-114 001 is a probiotic strain able to interact with the immune system and to interfere with gastrointestinal pathogens. The derived strain DN-114 001Rif was studied during its transit through the upper and distal intestine of human volunteers. Seven volunteers participated in the study, which involved intestinal intubation to sample ileal contents and collection of fecal samples, with a wash-out period of 8 days between the 2 steps. The retrieval of the probiotic was analyzed in the ileum every 2 h for 8 h following the ingestion of one dose of the test product and in the feces prior to, during, and after daily consumption of the test product for 8 days. Persistence of the probiotic amplifiable DNA was assessed using temporal temperature gradient gel electrophoresis and real-time PCR. Fluorescent in situ hybridization allowed analysis of the composition of the dominant digestive microbiota. The ingestion of L. casei DN-114 001Rif led to a significant and transient increase of its amplifiable DNA in ileal and fecal samples. This is related to a high stability in the composition of dominant groups of the gut microbiota. Data from ileal samples are scarce and our study confirms the potentiality for interaction between probiotics and the human immune system.

The influence of Lactobacillus rhamnosus LC705 together with Propionibacterium freudenreichii ssp. shermanii JS on potentially carcinogenic bacterial activity in human colon

The bacterial enzymes beta-glucosidase, beta-glucuronidase, and urease may contribute to the development of colon cancer by generating carcinogens. A reduction in the activity of these enzymes by certain lactic acid bacteria is considered to be beneficial. This study examined fecal beta-glucosidase, beta-glucuronidase, and urease activities during administration of Lactobacillus rhamnosus LC705 (LC705) together with Propionibacterium freudenreichii ssp shermanii JS (PJS). Thirty-eight healthy men participated in this randomized, double-blind, placebo-controlled, two-period crossover study with treatment periods of 4 weeks. Subjects consumed daily bacterial or placebo capsules. Bacterial capsules contained viable LC705 and PJS (2x10(10) CFU of each strain daily). The activities of beta-glucosidase, beta-glucuronidase and urease, recovery of LC705 and PJS, and counts of total lactobacilli and propionibacteria were determined from feces. The mean fecal counts of total lactobacilli and propionibacteria as well as strains LC705 and PJS were significantly increased during the administration of bacteria (3.5-, 13-, 80- and 11-fold, respectively). beta-glucosidase activity decreased by 10% (P=0.18) and urease activity by 13% (P=0.16) during bacterial supplementation versus placebo. The change in beta-glucosidase activity was negatively correlated with the change in propionibacteria counts (R=-0.350, P=0.039), being -2.68 versus 0.94 nmol/min/mg protein in subjects with increased and unchanged/decreased propionibacteria, respectively (P=0.003). To conclude, the administration of LC705 and PJS was followed by an increase in the fecal counts of lactobacilli and propionibacteria and a decrease in the activity of beta-glucosidase with increasing counts of propionibacteria.

The evidence to support health claims for probiotics

As the health benefits of ingesting live bacteria become more evident, foods are now being produced that contain probiotic bacteria. The data to support label health claims for probiotic products are often difficult to provide. The experimental evidence to identify probiotic microorganisms and to demonstrate their efficacy in clinical trials is more challenging than for other potential functional foods because effects are mediated by living microorganisms and may therefore be influenced by the status of these microorganisms. Clinical trials to show efficacy are expensive. Obtaining appropriate samples is difficult. A scientific consensus is building to support the claim that the ingestion of certain probiotic bacteria reduces lactose intolerance and can reduce the duration of rotavirus diarrheas. Some probiotic bacteria have "generally accepted as safe" status; proof of the safety of any probiotic is essential. Japanese health regulatory officials, using their Foods for Specific Health Use system, have approved human health claims for over 20 probiotic products. On the other hand, at this time, no probiotic product is sold in Canada that carries a label health claim. This illustrates the considerable discrepancies across countries in perception of health effects of probiotics.

Fate and effects of Camembert cheese micro-organisms in the human colonic microbiota of healthy volunteers after regular Camembert consumption

The objective of this study was to determine i) if Camembert cheese micro-organisms could be detected in fecal samples after regular consumption by human subjects and ii) the consequence of this consumption on global metabolic activities of the host colonic microbiota. An open human protocol was designed where 12 healthy volunteers were included: a 2-week period of fermented products exclusion followed by a 4-weeks Camembert ingestion period where 2x40 g/day of Camembert cheese was consumed. Stools were collected from the volunteers before consumption, twice during the ingestion period (2nd and 4th week) and once after a wash out period of 2 weeks. During the consumption of Camembert cheese, high levels of Lactococcus lactis and Leuconostoc mesenteroides were measured in fecal samples using real-time quantitative PCR, reaching median values of 8.2 and 7.5 Log(10) genome equivalents/g of stool. For Ln. mesenteroides, persistence was observed 15 days after the end of Camembert consumption. The survival of Geotrichum candidum was also assessed and the fecal concentration reached a median level of 7.1 Log(10) CFU/g in stools. Except a decreasing trend of the nitrate reductase activity, no significant modification was shown in the metabolic activities during this study.

Characterization of cecal microbiota and response to an orally administered lactobacillus probiotic strain in the broiler chicken

A probiotic Lactobacillus strain was given in drinking water to young broiler chickens from 1 to 19 days of age. Cecal contents were collected from 4- and 19-day-old chickens in treated and control groups. Enumeration of bacteria by culture on selective media showed a decrease in Clostridium perfringens carriage in the 4-day-old treated chickens, whereas coliforms and Lactobacillus populations were not significantly affected by the treatment. Fluorescent in situ hybridization analysis with 7 phylogenetic probes targeting the major groups of intestinal bacteria revealed that the Clostridium coccoides group accounted for more than 50% of the total bacteria in the cecum of 4-day-old chickens, whereas the bacterial community of 19-day-old chickens evolved towards a more diverse microbiota with Faecalibacterium prausnitzii (36%) and C. coccoides (22%) groups representing the predominant bacteria. No effect of the Lactobacillus strain supplementation was observed in the composition of the cecal microbiota assessed by fluorescent in situ hybridization with the 7 probes. Nevertheless, profiling of the cecal microbiota using temporal temperature gradient gel electrophoresis in combination with principal component analysis demonstrated an impact of the probiotic treatment on the overall bacterial community as well as on the Lactobacillus population.

Effects of probiotic Lactobacillus casei DN-114 001 in prevention of radiation-induced diarrhea: results from multicenter, randomized, placebo-controlled nutritional trial

PURPOSE

To determine whether a probiotic drink containing Lactobacillus casei DN-114 001 reduces the incidence of radiation-induced diarrhea in patients with gynecologic cancer.

METHODS AND MATERIALS

Patients who were undergoing pelvic radiotherapy (45-50 Gy, conventional fractionation) for either cervical carcinoma (radiotherapy and weekly cisplatin) or endometrial adenocarcinoma (postoperative radiotherapy) were randomly assigned to a probiotic drink or placebo, in a double-blind fashion. The probiotic drink consisted of liquid yogurt containing L. casei DN-114 001 at 10(8) CFU/g. The patients recorded the daily the number of bowel movements and scored the stool consistency using the Bristol scale. Diarrhea was graded weekly according the Common Toxicity Criteria system. The primary endpoint was to reduce the incidence of diarrhea, defined by a Common Toxicity Criteria Grade of 2 or greater or the need for loperamide.

RESULTS

A total of 85 patients were enrolled. Grade 2 or greater diarrhea and/or the use of loperamide was observed in 24 of 41 patients in the placebo group and 30 of 44 in the probiotic group (p = 0.568). No differences were found in the median time to the presentation of the primary endpoint. Probiotic intervention had a significant effect on stool consistency (p = 0.04). The median time for patients to present with Bristol scale stools of Type 6 or greater was 14 days for patients receiving the probiotic drink vs. 10 days for those receiving placebo.

CONCLUSION

Nutritional intervention with the probiotic drink containing L. casei DN-114 001 does not reduce the incidence of radiation-induced diarrhea as defined by a Common Toxicity Criteria Grade 2 or greater. However, it had a significant effect on stool consistency as measured by the Bristol scale.

The effect of a multispecies probiotic on the intestinal microbiota and bowel movements in healthy volunteers taking the antibiotic amoxycillin

BACKGROUND

One of the side effects of antimicrobial therapy is a disturbance of the intestinal microbiota potentially resulting in antibiotic-associated diarrhea (AAD). In this placebo-controlled double-blind study, the effect of a multispecies probiotic on the composition and metabolic activity of the intestinal microbiota and bowel habits was studied in healthy volunteers taking amoxycillin.

METHODS

Forty-one healthy volunteers were given 500 mg amoxycillin twice daily for 7 days and were randomized to either 5 g of a multispecies probiotic, Ecologic AAD (10(9) cfu/g), or placebo, twice daily for 14 days. Feces and questionnaires were collected on day 0, 7, 14, and 63. Feces was analyzed as to the composition of the intestinal microbiota, and beta-glucosidase activity, endotoxin concentration, Clostridium difficile toxin A, short chain fatty acids (SCFAs), and pH were determined. Bowel movements were scored according to the Bristol stool form scale.

RESULTS

Mean number of enterococci increased significantly from log 4.1 at day 0 to log 5.8 (day 7) and log 6.9 (day 14) cfu/g feces (P < 0.05) during probiotic intake. Although no other significant differences were observed between both intervention groups, within each group significant changes were found over time in both microbial composition and metabolic activity. Moreover, bowel movements with a frequency >or=3 per day for at least 2 days and/or a consistency >or=5 for at least 2 days were reported less frequently in the probiotic compared to the placebo group (48%vs 79%, P < 0.05).

CONCLUSIONS

Apart from an increase in enterococci no significant differences in microbial composition and metabolic activity were observed in the probiotic compared with the placebo group. However, changes over time were present in both groups, which differed significantly between the probiotic and the placebo arm, suggesting that the amoxycillin effect was modulated by probiotic intake. Moreover, the intake of a multispecies probiotic significantly reduced diarrhea-like bowel movements in healthy volunteers receiving amoxycillin.

Effect of a milk formula containing probiotics on the fecal microbiota of asian infants at risk of atopic diseases

The fecal microbiota of 37 infants with (n = 20) or without (n = 17) probiotic administration was evaluated on D 3, and at 1, 3, and 12 mo by fluorescence in situ hybridization-flow cytometry (FISH-FC), PCR, and bacteriological culture methods. They represent consecutive subjects of an ongoing double-blind, placebo-controlled trial on a probiotic formula (LGG and Bifidobacterium longum) administered during the first 6 mo of life. Despite varying composition in each baby, there was a general bacterial colonization pattern in the first year. Bifidobacteria increased markedly (p = 0.0003) with a parallel decrease in Enterobacteriaceae (p < 0.001) and Bacteroides-Prevotella (p = 0.005) populations. Eubacterium rectale-Clostridium coccoides (p < 0.001) and Atopobium (p = 0.039) groups also gradually increased. This overall pattern was unaffected by probiotic administration (p > 0.05). B. longum (p = 0.005) and Lactobacillus rhamnosus (p < 0.001) were detected more frequently in probiotic group during supplementation, but no difference after supplementation had ceased (p > 0.05). Cultured lactic acid bacteria were also more numerous in the probiotic-administered babies during treatment period (log CFU/g 8.4 versus 7.4; p = 0.035). Our results indicate that supplemented strains could be detected but did not persist in the bowel once probiotic administration had ceased.

Current and future uses of real-time polymerase chain reaction and microarrays in the study of intestinal microbiota, and probiotic use and effectiveness

Probiotics are defined as live microorganisms that confer a health benefit to the host when administered in adequate amounts. In addition to human health benefits, probiotics can improve various aspects of growth and performance in livestock and poultry, as well as control undesirable microorganisms in food animals. Studies indicate that probiotics can prevent or treat certain conditions, including atopic disease in infants, food allergy, infection after surgery, acute diarrhea, and symptoms associated with irritable bowel syndrome. Understanding the complete mechanism, effectiveness, and potential use of probiotics is limited by the availability and sensitivity of current methods (i.e., culturing techniques). In recent years, real-time polymerase chain reaction (PCR) and microarrays have become prominent and promising methods to examine quantitative changes of specific members of the microbial community and the influence of probiotics on the structure and function of human and animal intestinal ecosystems. Culture-independent studies have established that only a fraction of organisms present in feces are cultivable, therefore, results obtained by cultivation are limited. Conversely, in-depth knowledge of microbial genomes has enabled real-time PCR and microarrays to be more sensitive and has resulted in precise methods for comprehensive analysis of the complex gut microbiota. Additionally, these technologies can assess the influence of intestinal microorganisms on host metabolism, nutrient status, and disease. This paper reviews method technologies and applications of real-time PCR and microarray assays as they relate to the effect and use of probiotics on the intestinal microbiota and gastrointestinal disease.

Lactobacillus acidophilus 74-2 and Bifidobacterium animalis subsp lactis DGCC 420 modulate unspecific cellular immune response in healthy adults

OBJECTIVE

It was determined whether a combination of Lactobacillus acidophilus (L. acidophilus) 74-2 and Bifidobacterium animalis subsp lactis DGCC 420 (B. lactis 420) affect the faecal microbiota as well as immunological parameters and blood lipids in healthy adults.

DESIGN

A placebo-controlled, double-blinded, randomized crossover trial was conducted.

SUBJECTS

Twenty-six healthy volunteers (mean age 25 years) were recruited by advertising in academical buildings. All of them completed the study.

METHODS

After 3-week run-in period, half of the volunteers consumed 300 g/day of yoghurt supplement containing probiotic strains L. acidophilus 74-2 and B. lactis 420, and the other half received the placebo product for a period of 5 weeks. The two groups were crossed during the following 5-week period. Blood and faecal samples were collected at the end of each period. The faecal content of probiotic bacteria, faecal short-chain fatty acids (SCFA), serum lipids and plasma immune system biomarkers were evaluated.

RESULTS

Faecal proportions of L. acidophilus and of B. lactis increased significantly from 0.02 to 0.19 and 0.4 to 1.4% (P<0.05), respectively. Percentages of granulocytes and monocytes showing phagocytic activity were significantly elevated from 92 to 95% during probiotic intervention, whereas their oxidative burst activity and specific immune parameters remained unaffected. Fecal SCFA and serum cholesterol levels were not influenced by the probiotics. However, serum concentrations of triacylglyceroles decreased significantly by 11.6% (P<0.05) in the probiotic supplementation period.

CONCLUSIONS

L. acidophilus and B. lactis were recovered in faeces in significantly elevated numbers after supplementation. They are able to modulate unspecific cellular immune response indicated by the increased phagocytic activity.

Composition and metabolism of the intestinal microbiota in consumers and non-consumers of yogurt

The objective of the present study was to evaluate the impact of a regular consumption of yogurt on the composition and metabolism of the human intestinal microbiota. Adult subjects were selected on the basis of daily food records and divided into two groups: yogurt consumers (at least 200 g yogurt consumed per d, n 30); non-consumers (no yogurt, n 21). Their faecal microbiota was analysed using molecular methods (in situ hybridisation and PCR amplification combined with separation by denaturing gel electrophoresis) and its metabolic characteristics were assessed by measuring glycosidase, P-glucuronidase and reductase activities and profiling SCFA, neutral sterols and bile acids. The yogurt starter Lactobacillus delbrueckii ssp. bulgaricus (identity confirmed by 16S rRNA sequencing) was detected in 73% of faecal samples from fermented milk consumers v. 28% from non-consumers (P=0.003). In yogurt consumers, the level of Enterobacteriaceae was significantly lower (P=0.006) and 13-galactosidase activity was significantly increased (P=0.048). In addition, within this group, 3-galactosidase activity and the Bifidobacterium population were both positively correlated with the amount of fermented milk ingested (r 0.66, P<0.0001 and r 0.43, P=0.018, respectively). Apart from these effects, which can be considered beneficial to the host, no other major differences could be detected regarding the composition and metabolic activity of intestinal microbiota.