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PubMed1999

Review of probiotics available to modify gastrointestinal flora.

There is evidence that the oral consumption of micro-organisms produces a protective effect on the gut flora. A significant number of studies suggests that probiotics might have beneficial effects on several microbial disorders of the gut, but it is very difficult to define the clinical efficacy of such products. In this review, we report the results of studies on traveller's diarrhoea (TD), antibiotic associated diarrhoea (AAD) and acute diarrhoea (AD) in which various probiotic preparations have been used in controlled trials and been shown to have a beneficial therapeutic or prophylactic effect.

Anti-Bacterial Agents↗

PubMed2003

Immunobiotics and the probiotic evolution.

The term 'probiotic' was coined by the food industry to describe microbes beneficial to health. Scientific criticism based on poorly characterised isolates, soft clinical targets, and an absence of a mechanistic framework limited value of this concept. Current clinical and animal model studies support a role for certain 'probiotics', activating the common mucosal system through the stimulation of gut antigen-presenting cells to both promote protection and to switch regulatory mechanisms. It is concluded that a new term is required to identify bacteria that promote health through driving mucosal immune mechanisms, compared to those with strictly local effects. The term 'immunobiotics' is suggested as appropriate to fulfil this need.

Animals↗

PubMed2004

The probiotic Escherichia coli strain Nissle 1917 interferes with invasion of human intestinal epithelial cells by different enteroinvasive bacterial pathogens.

The probiotic Escherichia coli strain Nissle 1917 (Mutaflor) of serotype O6:K5:H1 was reported to protect gnotobiotic piglets from infection with Salmonella enterica serovar Typhimurium. An important virulence property of Salmonella is invasion of host epithelial cells. Therefore, we tested for interference of E. coli strain Nissle 1917 with Salmonella invasion of INT407 cells. Simultaneous administration of E. coli strain Nissle 1917 and Salmonella resulted in up to 70% reduction of Salmonella invasion efficiency. Furthermore, invasion of Yersinia enterocolitica, Shigella flexneri, Legionella pneumophila and even of Listeria monocytogenes were inhibited by the probiotic E. coli strain Nissle 1917 without affecting the viability of the invasive bacteria. The observed inhibition of invasion was not due to the production of microcins by the Nissle 1917 strain because its isogenic microcin-negative mutant SK22D was as effective as the parent strain. Reduced invasion rates were also achieved if strain Nissle 1917 was separated from the invasive bacteria as well as from the INT407 monolayer by a membrane non-permeable for bacteria. We conclude E. coli Nissle 1917 to interfere with bacterial invasion of INT407 cells via a secreted component and not relying on direct physical contact with either the invasive bacteria or the epithelial cells.

Antibiosis↗

PubMed2002

Probiotics and health: new facts and ideas.

Many trials on probiotics are now published that use established methods to demonstrate their clinical efficacy. Convincing progress has been made in the field of inflammatory bowel disease and allergy prevention in infants. Experimental studies show clear differences (and even sometimes opposite effects) between apparently closely related probiotics and suggest new mechanisms for the observed effects, such as immunostimulation by bacterial DNA and interaction with Toll-like receptors and dendritic cells in the gastrointestinal tract.

Bacterial Infections↗

PubMed2001

Phage-related DNA polymorphism in dairy and probiotic Lactobacillus.

Various DNA-based methods are presently being applied for identification of industrial bacterial cultures including dairy starter and probiotic strains of Lactobacillus. The success of strain-specific identification depends on the power of the DNA-based methods to reveal intraspecies DNA polymorphism. This study reveals that all eleven arbitrarily chosen Lactobacillus rhamnosus starter, laboratory and probiotic strains contain Lb. rhamnosus phage Lc-Nu related nucleotide sequences. One of these highly homologous regions in the genome of phage Lc-Nu was the 2.4kb HindIII fragment, which has been sequenced. Nucleotide sequence analysis suggested that one side of the 2.4kb HindIII fragment encodes a phage Lc-Nu helicase and accordingly represents an early gene region of phage Lc-Nu genome. Five forward and five reverse primers were derived from the nucleotide sequence of the 2.4kb HindIII fragment of phage Lc-Nu DNA for PCR-based identification of the eleven Lb. rhamnosus strains included in this study. Six different types of PCR product patterns were obtained. Among the patterns three were unique to particular Lb. rhamnosus strains. The results suggest that phage-related DNA sequences are, surprisingly, distributed widely among the Lb. rhamnosus strains, and that these sequences could also be a source of DNA polymorphism to apply for DNA-based identification of bacterial strains. Phage Lc-Nu related DNA homology was also found in the chromosome of Lb. casei, the species closely related to Lb. rhamnosus.

Bacteriophages↗

PubMed2003

Basic aspects and pharmacology of probiotics: an overview of pharmacokinetics, mechanisms of action and side-effects.

Probiotics have been defined as non-pathogenic micro-organisms that, when ingested, exert a positive influence on host health or physiology. Their pharmacology is more complex than that of inert drugs but is now being studied in detail. Some strains have a high survival capacity until they reach the faeces, whereas others are rapidly killed by acid and bile (a characteristic that can be used for the delivery of active intracellular components). Potential translocation and permanent colonization are rare but possible events; and should come under closer scrutiny. Mechanisms of action can be direct or indirect through modifications of the endogenous flora or through immunomodulation. The active components are poorly known but include bacterial formylated peptides, peptidoglycan cell wall constituents and nucleotides. Although the safety of commercial probiotics is excellent, this aspect should be studied in more detail, especially in immunocompromised hosts.

Animals↗

PubMed2002

Novel probiotics for the management of allergic inflammation.

Several pathologies of the gastrointestinal tract, particularly food allergy, are due to an exaggerated and imbalanced response of the gut mucosal immune system. The intestinal microflora is an important constituent of the gut mucosal barrier against food allergens and there is increasing evidence that one important acquired factor predisposing to food allergy in infants is the gut microflora. Indeed, the balance of bifidobacteria versus Clostridia in the neonatal flora appears to determine the allergic status in infants. In earlier studies, it was shown that the higher prevalence of allergies in infants fed standard formulas, compared to breast-fed infants, correlated with lower frequencies of bifidobacteria in their faeces. Certain Lactobacillus probiotic strains can have an inhibitory impact on allergic inflammation. The mechanisms implicated are still unclear, but it seems that they can involve both proteolytic and/or immunomodulatory functions. One challenge will be to find a probiotic strain that elicits all these functions and that fulfills all safety criteria.

Food Hypersensitivity↗

PubMed2002

Probiotics and Crohn's disease.

Antibiotics are often employed in the treatment of Crohn's disease, with interesting results. However indiscriminate suppression of intestinal bacteria may be harmful and long-term use of antibiotics is burdened by side-effects and by the risk of developing bacterial resistance. Manipulation of enteric flora with probiotic compounds would be a possible and appealing alternative. First aim of our study has been to investigate the efficacy of this probiotic in reducing the endoscopic recurrence rate or in reducing the severity of recurrent lesions at 1 year after surgery. Secondary goal has been the reduction of the clinical recurrence rate. Forty-five patients have been randomised to receive Lactobacillus rhamnosus strain GG or placebo for 12 months. The results have shown no differences in endoscopic and clinical remission between the two groups.

Crohn Disease↗

PubMed2002

Probiotics and atopic dermatitis. A new strategy in atopic dermatitis.

Over the last few decades, the prevalence of atopic dermatitis has been increasing from 2% to 100%, with 90% of cases within 5 years of age versus 6% between 6 and 10 years and 2% after 10 years, and environmental factors may possibly play an important role in this increase as in other atopic diseases. Many findings suggest an important role of atopy in atopic dermatitis; moreover, 40% of children with atopic dermatitis have food allergy and the removal of the food allergen from the patient's diet leads to a significant clinical improvement. In a possible scenario, IgE-bearing dendritic cells are likely to process allergens acquired in the gastrointestinal tract, circulate to the skin and activate local T cells. Cultures of beneficial live microorganisms characteristic of the commensal microflora are administered with probiotic functional foods in order to provide a microbial challenge for the maturation of gut-associated lymphoid tissue, which the infant often lacks. The probiotic effects are attributed to normalisation of the increased intestinal permeability and balancing gut microecology, improvement of the immunological defence barrier (IgA) of the intestine, alleviation of the intestinal inflammatory response, and downregulation of proinflammatory cytokines characteristic of local and systemic allergic inflammation.

Child↗

PubMed2002

Probiotics in antibiotic-associated diarrhoea.

Antibiotic-associated diarrhoea is a common event. In some cases, it could represent a life-threatening event. Clostridium difficile colitis is a further distinct complication of antibiotic administration. Treatment options for antibiotic-associated diarrhoea and Clostridium difficile colitis include supplementation with several types of probiotics, as overviewed in this paper. Three randomised, double-blind, controlled clinical trials show a therapeutic effect of Saccharomyces boulardii in antibiotic-associated diarrhoea. The efficacy of Lactobacillus acidophilus and bulgaricus has also been ascertained in two double-blind controlled studies. Other studies focusing on Lactobacillus as a new preventive agent for antibiotic-associated diarrhoea are not double-blind. Among these, a positive effect of Lactobacillus rhamnosus GG, Bifidobacterium longum and Enterococcus faecium SF68 has been reported. Effectiveness of probiotics in antibiotic-associated diarrhoea has, therefore, a consistent scientific rationale, however few studies have performed an assessment of bacterial recovery in stools, and this approach may be helpful in deciding a more rigorous dose standardisation.

Bifidobacterium↗

PubMed2003

Probiotics induce resistance to enteropathogens in a re-nourished mouse model.

Nutritional deficiency is commonly associated with impaired immune response and the relation between infection and malnutrition is synergic. Probiotics, especially lactic acid bacteria are immunomodulatory. The aim was to determine whether optimal doses of Lactobacillus casei and yogurt, used as adjuvants in a re-nutrition diet in a non-severe malnutrition experimental model, protect against Salmonella typhimurium and Escherichia coli. Groups of malnourished mice were used, which were re-nourished with milk for 7 or 14 d. After that, both groups of mice received the optimal doses of Lb. casei and yogurt supplements. We measured IgA+ and IgG+-B cells and phenotypic markers of T lymphocytes; CD3+, CD4+ and CD8+ cells. We also determined alphabeta and gammabeta T cell receptor (TCR). The ability to protect against Sal. typhimurium and Esch. coli infections and specific S-IgA were assessed. Probiotics complemented the effects of the re-nutrition diet, by stimulating recuperation of the activity of immune cells that improved protection against infections.

Animals↗

PubMed2005

Effect of fermented milk containing probiotic bacteria in the prevention of an enteroinvasive Escherichia coli infection in mice.

This study investigated the protective capacity of the oral administration of fermented milk containing the probiotic strains; Lactobacillus casei, Lb. delbrueckii subsp. bulgaricus and Streptococcus thermophilus, against enteroinvasive Escherichia coli infection in a murine (BALB/ c mice) model. Mice were fed for 2, 5 or 7 consecutive days with fermented milk diluted to a concentration of viable Lb. casei, Lb. delbrueckii subsp. bulgaricus and Strep. thermophilus of 10(7) cfu/ml. Phagocytic activity of peritoneal macrophages and the number of IgA+ cells in small and large intestine were determined at the end of the feeding periods. For the preventive effect against Esch. coli, animals were fed for 5 days (selected dose). Mice were challenged with an infective dose of enteroinvasive Esch. coli of 10(8) cfu/mouse. The colonization of liver and spleen and the secretory IgA specific for the pathogen in the intestinal fluid were determined (ELISA test). Results showed that the unspecific immune response enhanced itself after 5 consecutive days of the administration of this fermented milk (increase in the percentage of phagocytosis and number of IgA+ cells in the small intestine). Treated animals showed less Esch. coli colonization of liver than control mice and a higher secretory anti-Esch. coli IgA in the intestinal fluids. These results suggest that the protection against enteroinvasive Esch. coli infection observed for the fermented milk containing probiotic bacteria may be associated with an enhance of the intestinal mucosa immunity.

Animals↗

PubMed2001

Induction of nitric oxide synthesis by probiotic Lactobacillus rhamnosus GG in J774 macrophages and human T84 intestinal epithelial cells.

BACKGROUNDS AND AIMS: Probiotic Lactobacillus rhamnosus GG (LGG) has proved to be beneficial in the treatment of viral- and antibiotic-associated diarrhea but the mechanisms of action remain unknown. Nitric oxide (NO) is involved in the protective mechanisms in the gastrointestinal tract and may contribute to some of the beneficial effects of probiotics. The aim of the present study was to investigate if induction of NO synthesis is involved in the cellular actions of LGG. METHODS: NO synthesis and its regulation were measured in cultures of J774 murine macrophages and human T84 colon epithelial cells. NO production was measured as its metabolite nitrite accumulated into the culture medium. Inducible nitric oxide synthase (iNOS) protein and iNOS mRNA were detected by Western blot and RT-PCR, respectively. RESULTS: In J774 macrophages, LGG induced a low level production of NO in the presence of gamma interferon (IFNgamma) and it was inhibited by NOS inhibitors, cycloheximide and by a NF-kappa B inhibitor pyrrolidinedithiocarbamate. Accordingly, LGG and IFNgamma-stimulation increased iNOS mRNA and protein levels. T84 cells produced NO in response to LGG when first primed with a combination of IL-1beta, TNFalpha and IFNgamma. Lipoteichoic acid (LA), an antigenic structure in gram-positive bacteria, also induced NO formation in J774 cells in the presence of IFNgamma suggesting that LA may be the active component in LGG. CONCLUSIONS: LGG induces NO production in J774 macrophages and in human T84 colon epithelial cells through induction of iNOS by a mechanism involving activation of transcription factor NF-kappaB. Induction of iNOS and low-level synthesis of NO may be involved in the protective actions of LGG in the gastrointestinal tract.

Cell Line↗

PubMed2001

Dietary probiotic supplementation enhances natural killer cell activity in the elderly: an investigation of age-related immunological changes.

Many elderly subjects are at increased risk of infectious and noninfectious diseases due to an age-related decline in lymphoid cell activity (immunosenescence). Noninvasive means of enhancing cellular immunity are therefore desirable in the elderly. Previous reports have suggested that dietary supplementation could represent an effective means of enhancing the activity of circulating natural killer (NK) cells in the elderly. In the present study, we have conducted a pre-post intervention trial to determine the impact of dietary supplementation with probiotic lactic acid bacteria (LAB) on peripheral blood NK cell activity in healthy elderly subjects. Twenty-seven volunteers consumed low-fat/low-lactose milk supplemented with known immunostimulatory LAB strains (Lactobacillus rhamnosus HN001 or Bifidobacterium lactis HN019) for a period of 3 weeks. A dietary run-in of milk alone was shown to have no significant effect on NK cells. In contrast, the proportion of CD56-positive lymphocytes in peripheral circulation was higher following consumption of either LAB strain, and ex vivo PBMC tumoricidal activity against K562 cells was also increased. Supplementation with HN001 or HN019 increased tumoricidal activity by an average of 101 and 62%, respectively; these increases were significantly correlated with age, with subjects older than 70 years experiencing significantly greater improvements than those under 70 years. These results demonstrate that dietary consumption of probiotic LAB in a milk-based diet may offer benefit to elderly consumers to combat some of the deleterious effects of immunosenescence on cellular immunity.

Aged↗

PubMed2004

Modulation of the effect of dextran sulfate sodium-induced acute colitis by the administration of different probiotic strains of Lactobacillus and Bifidobacterium.

The pathogenic mechanism of inflammatory bowel diseases is not fully understood but colonic microflora including Lactobacillus and Bifidobacterium species may affect the induction of colonic inflammation. In this study the relative efficacy of different probiotic organisms in the prevention of colitis was compared in an induced rat colitis model. Three Lactobacillus strains and two Bifidobacterium strains were fed to Sprague-Dawley rats for 7 days prior to offering the rats 5% dextran sulfate sodium (DSS) in their drinking water to induce colitis and the administration of the probiotics continued for 7 days with the DSS. Colitis severity was assessed daily using a disease activity index (DAI). Samples were collected 7 days after colitis induction for intestinal bacterial flora and bacterial translocation. The DAI decreased significantly on days 4, 5, 6, and 7 in the Lactobacillus plantarum DSM 9843, Bifidobacterium sp. 3B1, and Bifidobacterium infantis DSM 15158 groups compared to the colitis control. It decreased significantly on days 5, 6, and 7 in the Bifidobacterium infantis DSM 15158 group compared to the Lactobacillus paracaesi DSM 13434 and Lactobacillus gasseri 5B3 groups. It also decreased significantly on day 7 in the L. plantarum DSM 9843 group compared to the L. gasseri 5B3 group. Bacterial translocation to the mesenteric lymph nodes decreased significantly in all treatment groups compared to the colitis control. Enterobacteriaceae bacterial translocation to the liver decreased in all treatment groups compared to the colitis control. Administration of certain strains of Lactobacillus and Bifidobacterium significantly improves the DAI and reduces bacterial translocation, and L. plantarum DSM 9843, Bifidobacterium sp. 3B1, and Bifidobacterium infantis DSM 15158 seem to have the best effect.

Acute Disease↗

PubMed2002

Probiotics and food-allergic diseases.

The definition of probiotics is always evolving, since it includes natural live micro-organisms, cellular subfractions, as well as genetically engineered derivatives or proteins. The scope of probiotic administration is beneficial change of the intestinal microflora, and improvement of non immune or immune resistance in the intestinal tract. Very few controlled human studies have been reported, but many in vitro and experimental animal studies point to their safety and potentially useful applications. We shall review the published reports and discuss mainly the prospective uses in the field of allergic diseases, with reference to the implication of the natural (innate) immune system as regulator of the development of abnormal responses to ingested food antigens.

Animals↗

PubMed2003

Oral and intestinal microflora in 5-fluorouracil treated rats, translocation to cervical and mesenteric lymph nodes and effects of probiotic bacteria.

Serious systemic infections may occur during cancer chemotherapy due to disturbances in the oropharyngeal and gastrointestinal microflora, impaired mucosal barrier functions and immunosuppression. Bacteria may spread from the gastrointestinal tract to the regional lymph nodes. The routes for bacterial spread from the oral cavity are less well known. In the present study we investigated changes in the oral and intestinal microfloras in rats given 50 mg/kg 5-fluorouracil (5-FU) i.v. for 6 days. Bacterial dissemination to the lymph nodes draining the oral cavity and the lymph nodes draining the gastrointestinal tract was examined. Effects of adding the probiotic strain Lactobacillus plantarum 299v in the drinking water to the rats were measured. 5-FU treatment caused an increase in the number of facultative and strictly anaerobic bacteria in biopsies from the oral cavity and an increase in the number of facultative anaerobes in the large intestine. The proportion of facultative gram-negative rods increased in both the oral cavity and intestine. Bacteria translocated to both the cervical and mesenteric lymph nodes in untreated animals and increased in numbers after 5-FU treatment due to an increase in the number of facultative gram-negative rods. Treatment with L. plantarum 299v improved food intake and body weight in 5-FU-treated rats. It also reduced the 5-FU-induced raise in the total numbers of facultative anaerobes in the intestine, but did not reduce translocation and did not prevent diarrhea. This study reinforces the oral cavity, along with the gastrointestinal tract, as a source for bacterial dissemination. The use of probiotic bacteria may reduce some side effects of 5-FU treatment.

Animals↗

PubMed2000

The effect of a probiotic milk product on plasma cholesterol: a meta-analysis of short-term intervention studies.

INTRODUCTION: Certain fermented dairy milk products may have beneficial effects on plasma cholesterol levels. However, a number of studies have produced conflicting results as to whether dietary supplementation by a probiotic dairy product containing the bacteria culture Causido(R) reduces plasma cholesterol. OBJECTIVE: To conduct a meta-analysis of intervention studies to evaluate the effect of the Causido(R) culture on plasma total cholesterol and low-density lipoprotein (LDL)-cholesterol. THE PROBIOTIC MILK PRODUCT: The yoghurt product Gaio(R) is fermented with Causido(R), composed of one strain of Enterococcus faecium (human species) with the proposed cholesterol-lowering effect, and two strains of Streptococcus thermophilus. STUDY INCLUSION AND DATA EXTRACTION: Six studies were identified from a literature search and from the yoghurt producer. All studies met the inclusion criteria. Summary data for plasma concentrations of total cholesterol and LDL-cholesterol were extracted from the original publications or by personal request to the authors. Data from 4-8 weeks of treatment duration was used. STATISTICAL ANALYSIS: We performed a traditional meta-analysis where mean differences between intervention and control of the pre-post changes in total cholesterol and LDL-cholesterol were calculated, as well as 95% confidence intervals (CIs). RESULTS: In the six studies included in the meta-analysis, the Gaio(R) interventions produced changes in total cholesterol above those of the control groups ranging from -0.02 to -1.02 mmol/l and in LDL-cholesterol ranging from -0.02 to -1.15 mmol/l. After inclusion of an open-label study, the meta-analysis of the double-blind studies showed that Gaio(R) as compared to the control group changed total cholesterol by -0.22 mmol/l (95% CI: -0.35 to -0.08, P<0.01) and LDL-cholesterol by -0.20 mmol/l (95% CI: -0.33 to -0.06, P<0.005). The outcome was essentially the same if all studies were included. CONCLUSIONS: The present meta-analysis of controlled short-term intervention studies shows that the fermented yoghurt product produced a 4% decrease in total cholesterol and a 5% decrease in LDL-cholesterol when the open-label study is excluded. To demonstrate sustained effects on blood lipids, long-term studies are required. SPONSORSHIP: MD Foods A/S, Denmark.

Adult↗