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PubMed2006

Short-chain fructooligosaccharides, in spite of being fermented in the upper part of the large intestine, have anti-inflammatory activity in the TNBS model of colitis.

Previous studies have demonstrated the anti-inflammatory effect of fructooligosaccharides (FOS) on intestinal inflammation. The aim of the present study was to elucidate whether the colonic fermentation of these carbohydrates is a pre-requisite for this anti-inflammatory activity.With this aim short chain-FOS (SC-FOS) were used for an in vitro fermentation to elucidate the time of fermentation of these compounds. For the in vivo experiments female Wistar rats were fed several diets with different sources of fibre (5 g/kg): cellulose for control rats (n = 30) or SC-FOS (n = 20) with a high content of kestose (GF(2)) for the SC-FOS group. After one month of feeding the different diets 10 rats from each group were sacrificed to analyze cecal and colonic microflora, SCFA production and pH of intestinal contents. A distal colonic inflammation was induced to other 10 rats from each group by the administration of 10 mg of TNBS dissolved in 0.25 ml of 50% ethanol (v/v). The rest of the rats from the control group (n = 10) were rendered healthy. One week after TNBS treatment rats were sacrificed and several inflammatory parameters as well as intestinal microbiota and SCFA contents were analyzed. In vitro fermentation experiments showed that SC-FOS are fermented during the first 12 h after incorporating the oligosaccharides to intestinal contents, thus suggesting a preferential fermentation of these carbohydrates in the ileum and cecum. In fact, SC-FOS increased cecal lactobacilli and bifidobacteria counts as well as SCFA production in healthy rats. In colitic rats, SC-FOS feeding caused a decrease of MPO activity, leukotriene B4 (LTB4) production and iNOS expression. This anti-inflammatory effect was evidenced macroscopically by a significant reduction in the extent of colonic damage. SC-FOS also promoted a more favorable intestinal microbiota, increasing lactobacilli and bifidobacteria counts. In conclusion, although oligosaccharides are preferentially fermented in the upper parts of the large intestine, its prebiotic effect is extended to the distal colonic segments, thus exerting a positive effect on colonic inflammation.

Animals↗

PubMed2026

Effects of Acalypha australis L. Extract on Growth Performance, Antioxidant Capacity and Intestinal Microbial Composition in Weaned Piglets.

The objective of this study was to investigate the effects of Acalypha australis L. extract (ALE) on the growth performance and intestinal health in piglets. A total of 24 weaned piglets were randomly allocated to three groups: the control group (CON), which was fed a basal diet, and the ALE0.5 and ALE1.0 groups, which were fed the basal diet supplemented with 0.5 and 1.0 g/kg of ALE, respectively. The measured variables included growth performance, digestive enzyme activity, intestinal morphology, antioxidant capacity, and intestinal microbiota and metabolites. The results showed that, compared to the CON group, supplementation of 1.0 g/kg ALE in the diets of weaned piglets significantly increased the ratio of gain to feed from 15 to 21 days (p < 0.05), decreased the diarrhea rate from Days 15 to 21 and Days 0 to 21 (p < 0.05), and increased the activities of pancreatic α-amylase, lipase, trypsin, and chymotrypsin, as well as duodenal α-amylase, lipase, and trypsin, and jejunal maltase and sucrase (p < 0.05). Additionally, supplementation of 1.0 g/kg ALE in the diet significantly improved the intestinal morphology of the duodenum and jejunum, as well as the expression of intestinal barrier-related genes in the small intestine (p < 0.05). Moreover, it significantly increased serum glutathione peroxidase activity and jejunal and ileal superoxide dismutase activities (p < 0.05), and also significantly increased the colonic propionic acid concentration of piglets (p < 0.05). The ALE supplementation increased the abundance of the colonic marker bacteria Collinsella in the piglets and influenced pathways related to amino acid metabolism, carbohydrate metabolism, and lipid metabolism. ALE can serve as a potential natural feed additive to regulate the structure of intestinal microbiota and metabolic pathways, enhance antioxidant capacity, improve intestinal health, reduce diarrhea incidence, and ultimately promote the growth performance of piglets.

Acalypha australis L. extract↗

PubMed2003

Application of prebiotics and probiotics in poultry production.

The intestinal microbiota, epithelium, and immune system provide resistance to enteric pathogens. Recent data suggest that resistance is not solely due to the sum of the components, but that cross-talk between these components is also involved in modulating this resistance. Inhibition of pathogens by the intestinal microbiota has been called bacterial antagonism, bacterial interference, barrier effect, colonization resistance, and competitive exclusion. Mechanisms by which the indigenous intestinal bacteria inhibit pathogens include competition for colonization sites, competition for nutrients, production of toxic compounds, or stimulation of the immune system. These mechanisms are not mutually exclusive, and inhibition may comprise one, several, or all of these mechanisms. Consumption of fermented foods has been associated with improved health, and lactic acid bacteria (lactobacilli and bifidobacteria) have been implicated as the causative agents for this improved health. Research over the last century has shown that lactic acid bacteria and certain other microorganisms can increase resistance to disease and that lactic acid bacteria can be enriched in the intestinal tract by feeding specific carbohydrates. Increased bacterial resistance to antibiotics in humans has caused an increase in public and governmental interest in eliminating sub-therapeutic use of antibiotics in livestock. An alternative approach to sub-therapeutic antibiotics in livestock is the use of probiotic microorganisms, prebiotic substrates that enrich certain bacterial populations, or synbiotic combinations of prebiotics and probiotics. Research is focused on identifying beneficial bacterial strains and substrates along with the conditions under which they are effective.

Animals↗

PubMed2004

Characterization of faecal enterococci from rabbits for the selection of probiotic strains.

AIMS: To characterize the facultative anaerobic intestinal microbiota of healthy rabbits, especially enterococci, for the selection of potential probiotic strains. METHODS AND RESULTS: Phenotypic and molecular methods were used to identify enterococcal isolates. Results obtained indicated that enterococcal microbiota widely varied among individuals both in size and in composition. Antibacterial and haemolytic activities, and resistance to acid and bile salts were determined. A small group of strains produced bacteriocins active against listeriae and indigenous clostridia and therefore they were selected as potential probiotics. One such strain, 8G, was assayed for colonization capacity. Results obtained suggested that the fate of the introduced strain depended on the composition of the enterococcal indigenous microbiota. CONCLUSIONS: Enterococcus faecalis and Ent. faecium are the predominant enterococcal species in the gut of rabbits. Other species of lactic acid bacteria were not recovered. SIGNIFICANCE AND IMPACT OF THE STUDY: The enterococcal intestinal microbiota of healthy rabbits has been characterized in detail. Monitoring the fate of an introduced probiotic in vivo is required in order to evaluate potential probiotic strains.

Animals↗

PubMed2006

Phylogeny of human intestinal bacteria that activate the dietary lignan secoisolariciresinol diglucoside.

The human intestinal microbiota is essential for the conversion of the dietary lignan secoisolariciresinol diglucoside (SDG) via secoisolariciresinol (SECO) to the enterolignans enterodiol (ED) and enterolactone (EL). However, knowledge of the species that catalyse the underlying reactions is scant. Therefore, we focused our attention on the identification of intestinal bacteria involved in the conversion of SDG. Strains of Bacteroides distasonis, Bacteroides fragilis, Bacteroides ovatus and Clostridium cocleatum, as well as the newly isolated strain Clostridium sp. SDG-Mt85-3Db, deglycosylated SDG. Demethylation of SECO was catalysed by strains of Butyribacterium methylotrophicum, Eubacterium callanderi, Eubacterium limosum and Peptostreptococcus productus. Dehydroxylation of SECO was catalysed by strains of Clostridium scindens and Eggerthella lenta. Finally, the newly isolated strain ED-Mt61/PYG-s6 catalysed the dehydrogenation of ED to EL. The results indicate that the activation of SDG involves phylogenetically diverse bacteria, most of which are members of the dominant human intestinal microbiota.

4-Butyrolactone↗

PubMed2006

Bifidogenic effects of solid weaning foods with added prebiotic oligosaccharides: a randomised controlled clinical trial.

OBJECTIVES: Breast-fed infants have relatively high proportions of faecal bifidobacteria. This bifidogenic microbiota is at least partly explained by the high levels of prebiotic oligosaccharides in human milk. The present study aimed at testing the effect of solid foods with added prebiotic galacto- and fructo-oligosaccharides (GOS/FOS) on the composition of the intestinal microbiota of fully formula-fed infants during the weaning period. METHODS: The study was a double-blind, randomised trial with an intervention period of 6 weeks. Infants aged 4 to 6 months who were about to start consuming solid foods were randomised to receive either weaning products with a mixture of GOS/FOS or control weaning products with maltodextrin. After an adjustment period, the presented daily dose of GOS/FOS was 4.5 g. Total numbers of bacteria and bifidobacteria in faecal samples were analysed with fluorescent in situ hybridization. RESULTS: Thirty-five infants were included in the study, and 20 infants were included in a per-protocol analysis. In the GOS/FOS group, the faecal percentage of bifidobacteria significantly increased from 43% to 57% (P = 0.031) from week 0 to week 6, but did not significantly change in the control group (36% and 32%, respectively; P = 0.387). The change in the percentage of bifidobacteria between week 0 and week 6 in the GOS/FOS was significantly different from this change in the control group (P = 0.026). CONCLUSIONS: We conclude that addition of GOS/FOS to solid foods induces an increase in the faecal proportion of bifidobacteria in the intestinal microbiota of fully formula-fed infants with an established, mixed-type microbiota in the weaning period.

Bifidobacterium↗

PubMed2002

Gut bacteria and health foods--the European perspective.

Probiotics, prebiotics, and synbiotics aimed at improving intestinal health currently represent the largest segment of the functional foods market in Europe, Japan and Australia. Evidence continues to emerge demonstrating that these ingredients have the potential to improve human health in specific intestinal disorders. The European Commission, through its 5th Framework Programme, is presently focusing on a substantial effort in the science of the intestinal microbiota, its interaction with its host and methods to manipulate its composition and activity for the improvement of human health and well being. Eight multicentre and multidisciplinary research projects now cover a range of topics required for the development of efficacious probiotic foods, from understanding probiotic mechanisms at a molecular level; developing technologies to ensure delivery of stable products; and demonstrating safety and efficacy of specific probiotics in defined treatment targets. This concerted research effort promises to provide us with an enhanced understanding of the human intestinal microbiota's role in health and disease, and new approaches and products to tackle a variety of intestinal problems.

Digestive System↗

PubMedDate not supplied

[Comparative microbiological study of fresh and heat-treated yoghurt in an in vivo animal model].

In an acute assay, rats fasted for 24 h were sounded with 2 ml of fresh yogurt, sterilised yogurt or distilled water, and sacrificed at 2, 4, 8 and 24 h. They were compared with non-sounded rats. The survival of the lactic bacteria of the yogurt administered in the animals' stomach and intestines was determined, and the bacteria isolated were to the Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus profiles belonging to the strains isolated originally from the yogurt. Counts of the total number of microorganisms that were grown in lactobacilli and lactic streptococci media were also made. Analyses of the different types of resulting colonies in the lactobacilli and lactic streptococci media was performed. No L. delbrueckii subsp. bulgaricus or S. thermophilus were characterized in this acute assay. The statistical analysis of the results did not show significant differences in the log UFC. g-1, of the intestinal microbiota microorganisms of the three groups of animals in any of the times. In a chronic assay, three groups of animals, after 30 days of nourishment ad libitum with either a semisynthetic diet with 10% of fresh yogurt, or with 10% of sterilised yogurt or controls, housed in individual metabolism cells, were sacrificed. The results did not show meaningful differences in the long UFC. g-1 of the intestinal microbiota microorganisms from the three groups of animals in any of the times. In turn, in the study of the different types of colonies resulting in the lactobacilli and lactic streptococci media, no L. delbrueckii subsp. bulgaricus or S. thermophilus were characterised in this chronic assay. The results did not show meaningful differences in the log CFU. g-1 of the intestinal flora microorganisms from the three groups of animals in any of the times. In turn, no L. delbrueckii subsp. bulgaricus or S. thermophilus were characterised in this chronic assay.

Animals↗

PubMed2000

Influence of bacteria from the duodenal microbiota of patients with symptomatic giardiasis on the pathogenicity of Giardia duodenalis in gnotoxenic mice.

Recent studies have shown that the intestinal microbiota is essential for the pathogenicity but not for the multiplication of Giardia duodenalis in the intestinal lumen. The microbial components responsible for this phenomenon are not known. Twenty-eight facultative and three strictly anaerobic micro-organisms were isolated from the dominant duodenal microbiota of five patients with symptomatic giardiasis. The bacterial combinations from each patient were associated with groups (GN) of germ-free mice. Five days after the association, when their faecal populations ranged from 10(7) to 10(9) cfu/g, all groups were inoculated intragastrically with 10(5) viable trophozoites of G. duodenalis strain BT6. Two groups of germ-free (GF) and conventional (CV1) mice were also infected. Gnotobiotic animals were killed 10 days after infection and GF and CV1 animals were killed 10, 20 and 30 days after infection. More marked pathological alterations were detected in CV1 mice when compared with GF animals. Gnotobiotic animals showed intermediate pathological alterations between CV1 and GF mice. The CV1 and GF groups became infected by day 3 and faecal cyst levels were similar in both groups throughout the experiment. Total and G. duodenalis-specific IgA levels in the intestinal fluid and G. duodenalis-specific IgM and IgG levels in the serum increased during the infection and were higher in CV1 animals at all times tested when compared with GF mice. The present results confirm the stimulatory activity of the intestinal microbiota on the pathogenicity of G. duodenalis, and some combinations of microbial components of the dominant duodenal ecosystem from patients with symptomatic giardiasis can partially develop this function. However, none of these combinations was able to stimulate the protozoan pathogenicity in the same manner as the entire intestinal microbiota.

Animals↗

PubMed2006

Effects of long-term ingestion of difructose anhydride III (DFA III) on intestinal bacteria and bile acid metabolism in humans.

Changes in the intestinal microbiota of 10 human subjects with long-term ingestion of 3 g/d difructose anhydride III (DFA III; 4 persons, 2 months; 3 persons, 6 months; and 3 persons, 12 months) were examined by denaturing gradient gel electrophoresis (DGGE). According to the answers to questionnaires, the subjects were divided into two groups (constipated and normal). The DGGE profile was different for every individual and each subject had unique profiles of intestinal microbiota. In the DGGE profiles of constipated subjects, the intensities of bands related to Bacteroides spp. increased. Moreover, the DFA III-assimilating bacteria, Ruminococcus sp. were isolated from subjects who ingested DFA III for 12 months. These strains showed 95% similarity of their 16S rDNA sequences with that of Ruminococcus obeum ATCC 29174(T) (X85101) and produced large amounts of acetic acid. DFA III ingestion for 2 months tended to increase total organic acids in feces, and tended to decrease fecal pH and the secondary bile acid (SBA) ratio in total bile acids. The SBA ratio in total bile acids corresponded to fecal pH. The production of SBA was decreased by low pH in vitro. These results indicated that DFA III ingestion in humans tended to lower intestinal pH, inhibited bile acid 7alpha-dehydroxylation activities and also tended to decrease the SBA ratios in total bile acids. Moreover, as another cause for the decrease in the SBA ratio in total bile acids, it was suggested that the number of bile acid 7alpha-dehydroxylating bacteria were decreased by DFA III ingestion.

Adult↗

PubMed2025

Interaction of host gene-gut microbiota in male grading of Macrobrachium rosenbergii.

UNLABELLED: The giant freshwater prawn (GFP; Macrobrachium rosenbergii), a crustacean of high nutritional and economic value, is crucial for aquaculture. During the same growth cycle, male GFPs develop into three distinct forms: small males, orange claw males, and blue claw males. These morphotypes display varying social behaviors, which severely constrain their industrial development. To address this, this study collected male GFP samples at critical developmental time points (100, 110, and 120 days post-hatching) for phenotypic trait measurement and analysis to obtain external morphological data. Through gut microbiota diversity analysis, we identified key gut bacteria (Lactococcus garvieae and Lactobacillus taiwanensis) influencing male morphotype differentiation. Transcriptomic analysis revealed host Kyoto Encyclopedia of Gene and Genome pathways and key genes (Wnt-6, CTSB, CTSL, PPAE, and TP53) associated with morphotype differentiation. The interactions among phenotypic traits, gut microbiota, and key genes were systematically studied through association analysis. Weighted gene co-expression network analysis was employed to construct co-expression modules, from which critical gene modules influencing phenotypic variation were identified. Through association network analysis, we established an "Achromobacter-CD-TRINITY_DN93139_c0_g2 (calpain clp-1)" interaction model. Our findings provide novel insights into the genetic enhancement of GFPs and offer guidelines for future research regarding gut symbiotic bacteria and breeding initiatives. IMPORTANCE: Male Macrobrachium rosenbergii (giant freshwater prawn [GFP]) in the same growth cycle will develop into small males, orange claw males, and blue claw males. This individual heterogeneity in growth significantly impacts the benefits of aquaculture. However, the factors influencing the differentiation of male GFP morphotype remain unclear. This study analyzed the phenotypic data of various GFP levels, the structure of the intestinal microbiota, and the differential genes within the gonadal transcriptome at critical time points of male GFP-level type differentiation. The aim was to explore the potential role of intestinal microbiota and differential genes in this phenomenon. This study offers new insights into the research on the phenomenon of male GFP-level type differentiation.

Animals↗

PubMed2003

Effects of tylosin on bacterial mucolysis, Clostridium perfringens colonization, and intestinal barrier function in a chick model of necrotic enteritis.

Necrotic enteritis (NE) is a worldwide poultry disease caused by the alpha toxin-producing bacterium Clostridium perfringens. Disease risk factors include concurrent coccidial infection and the dietary use of cereal grains high in nonstarch polysaccharides (NSP), such as wheat, barley, rye, and oats. Outbreaks of NE can be prevented or treated by the use of in-feed antibiotics. However, the current debate regarding the prophylactic use of antibiotics in animal diets necessitates a better understanding of factors that influence intestinal colonization by C. perfringens as well as the pathophysiological consequences of its growth. We report a study with a chick model of NE, which used molecular (16S rRNA gene [16S rDNA]) and culture-based microbiological techniques to investigate the impact of the macrolide antibiotic tylosin phosphate (100 ppm) and a dietary NSP (pectin) on the community structure of the small intestinal microbiota relative to colonization by C. perfringens. The effects of tylosin and pectin on mucolytic activity of the microbiota and C. perfringens colonization and their relationship to pathological indices of NE were of particular interest. The data demonstrate that tylosin reduced the percentage of mucolytic bacteria in general and the concentration of C. perfringens in particular, and these responses correlated in a temporal fashion with a reduction in the occurrence of NE lesions and an improvement in barrier function. The presence of pectin did not significantly affect the variables measured. Thus, it appears that tylosin can control NE through its modulation of C. perfringens colonization and the mucolytic activity of the intestinal microbiota.

Animal Feed↗

PubMed2003

Intestinal microflora in early infancy: composition and development.

The neonatal intestinal microbiota is a complex ecosystem composed of numerous genera, species and strains of bacteria. This enormous cell mass performs a variety of unique activities that affect both the colonic and systemic physiology. Its primary activities include nutritive, metabolic, immunological and protective functions. Most studies of infants have been based on faecal samples using the classical plating techniques with culturing on specific media. The limitations of these methods must be taken into account when evaluating the varying results of the different studies. The establishment of the gut microbial population is not strictly a succession in the ecological sense; it is rather a complex process influenced by microbial and host interactions and by external and internal factors. The climax intestinal flora is attained in successive stages. The foetal intestine is sterile and bathed in swallowed amniotic fluid. Following delivery, multiple different antigens challenge the intestine of the newborn. The maternal intestinal flora is a source of bacteria for the neonatal gut. The bacterial flora is usually heterogeneous during the first few days of life, independently of feeding habits. After the first week of life, a stable bacterial flora is usually established. In full-term infants a diet of breast milk induces the development of a flora rich in Bifidobacterium spp. Other obligate anaerobes, such as Clostridium spp. and Bacteroides spp., are more rarely isolated and also enterobacteria and enterococci are relatively few. During the corresponding period, formula-fed babies are often colonized by other anaerobes in addition to bifidobacteria and by facultatively anaerobic bacteria; the development of a "bifidus flora" is unusual. In other studies the presence of a consistent number of bifidobacteria in infants delivered in large urban hospitals has not been demonstrated, whether the babies were bottle fed or exclusively breastfed. The predominant faecal bacteria were coliforms and bacteroides. According to these studies, environmental factors may be more important than breastfeeding in gut colonization after delivery. Environmental factors are indeed extremely important for the intestinal colonization of infants born by caesarean section. In these infants, the establishment of a stable flora characterized by a low incidence of Bacteroides spp. and by the isolation of few other bacteria is consistently delayed. In extremely low-birthweight infants, hospitalization in neonatal intensive care units, characterized by prolonged antibiotic therapy, parenteral nutrition, delayed oral feedings and intubation seems to affect the composition of the intestinal microbiota. The gut is colonized by a small number of bacterial species; Lactobacillus and Bifidobacteria spp. are seldom, if ever, identified. According to the few studies so far performed, the predominant species are Enterococcus faecalis, E. coli, Enterobacter cloacae, Klebsiella pneumoniae, Staphylococcus epidermidis and Staphylococcus haemolyticus. Hygienic conditions and antimicrobial procedures strongly influence the intestinal colonization pattern.

Anti-Bacterial Agents↗

PubMed2004

In vitro alterations of intestinal bacterial microbiota in fecal samples during storage.

The human gastrointestinal tract harbors an extremely diverse and complex microbial ecosystem. Most of the existent data about the enteric microflora have been generated using stool samples, but the collection and storage of fecal samples are often problematic. The influence of the storage of stool samples on the bacterial diversity and the degradation of bacterial DNA was analysed in this study. Stool samples from 5 healthy volunteers were exposed to different storage temperatures and durations. The bacterial diversity and the amount of intact bacterial DNA were analysed by single-stranded conformation polymorphism analysis (SSCP) and real-time polymerase chain reaction (PCR), both using a 16S rDNA approach. Additionally, biopsy specimens were taken from 3 of the 5 individuals to compare fecal and mucosal flora. The bacterial diversity of the fecal flora and the total number of bacteria were significantly reduced after 8 and 24 hours at both room temperature and 4 degrees C. The mucosa-associated bacterial microflora showed substantial differences compared with the fecal flora. The observed alterations of fecal flora during storage point to the difficulty of the molecular analysis of the bacterial diversity and the enumeration of bacterial cells in fecal samples.

Adult↗

PubMed2001

Effects of probiotic administration upon the composition and enzymatic activity of human fecal microbiota in patients with irritable bowel syndrome or functional diarrhea.

In a clinical trial, 10 patients suffering from irritable bowel syndrome or functional diarrhea were administered the probiotic preparation VSL-3. Preliminary results indicated that administration of VSL-3 improved the clinical picture and changed the composition and biochemistry of fecal microbiota. Titer variations of intestinal bacterial groups were evaluated by culture and PCR techniques. A significant increase in lactobacilli, bifidobacteria and Streptococcus thermophilus was observed as a consequence of probiotic treatment, while enterococci, coliforms, Bacteroides and Clostridium perfringens did not change significantly. The strains Bifidobacterium infantis Y1 and Bifidobacterium breve Y8, included in VSL-3, were specifically detected in feces of patients treated with the probiotic by using strain-specific PCR primers. In addition, fecal beta-galactosidase increased and urease activities decreased as a result of changes in the intestinal microbiota induced by VSL-3 administration.

Adult↗

PubMed1999

Influences of microbiota on intestinal immune system development.

The normal colonization of the mammalian intestine with commensal microbes is hypothesized to drive the development of the humoral and cellular mucosal immune systems during neonatal life and to maintain the physiologically normal steady state of inflammation in the gut throughout life. Neonatal conventionally reared mice and germ-free, deliberately colonized adult mice (gnotobiotic mice) were used to examine the efficacy of certain intestinal microbes.

Animals↗

PubMed2006

The front line of enteric host defense against unwelcome intrusion of harmful microorganisms: mucins, antimicrobial peptides, and microbiota.

The intestinal tract is a complex ecosystem that combines resident microbiota and the cells of various phenotypes with complex metabolic activities that line the epithelial wall. The intestinal cells that make up the epithelium provide physical and chemical barriers that protect the host against the unwanted intrusion of microorganisms that hijack the cellular molecules and signaling pathways of the host and become pathogenic. Some of the organisms making up the intestinal microbiota also have microbicidal effects that contribute to the barrier against enteric pathogens. This review describes the two cell lineages present in the intestinal epithelium: the goblet cells and the Paneth cells, both of which play a pivotal role in the first line of enteric defense by producing mucus and antimicrobial peptides, respectively. We also analyze recent insights into the intestinal microbiota and the mechanisms by which some resident species act as a barrier to enteric pathogens. Moreover, this review examines whether the cells producing mucins or antimicrobial peptides and the resident microbiota act in partnership and whether they function individually and/or synergistically to provide the host with an effective front line of defense against harmful enteric pathogens.

Animals↗

PubMed2006

Bacterial and fungal microbiota in relation to probiotic therapy (VSL#3) in pouchitis.

BACKGROUND: The intestinal microbiota plays a critical role in the pathophysiology of pouchitis, a major complication after ileal pouch anal anastomosis in patients with ulcerative colitis. Recently, controlled trials have demonstrated that probiotics are effective in maintenance of remission in pouchitis patients. However, the mechanism by which therapy with probiotics works remains elusive. This study explores the role of the bacterial and fungal flora in a controlled trial for maintenance of remission in pouchitis patients with the probiotic VSL#3 compound. METHODS: The mucosa associated pouch microbiota was investigated before and after therapy with VSL#3 by analysis of endoscopic biopsies using ribosomal DNA/RNA based community fingerprint analysis, clone libraries, real time polymerase chain reaction (PCR), and fluorescence in situ hybridisation. Patients were recruited from a placebo controlled remission maintenance trial with VSL#3. RESULTS: Patients who developed pouchitis while treated with placebo had low bacterial and high fungal diversity. Bacterial diversity was increased and fungal diversity was reduced in patients in remission maintained with VSL#3 (p = 0.001). Real time PCR experiments demonstrated that VSL#3 increased the total number of bacterial cells (p = 0.002) and modified the spectrum of bacteria towards anaerobic species. Taxa specific clone libraries for Lactobacilli and Bifidobacteria showed that the richness and spectrum of these bacteria were altered under probiotic therapy. CONCLUSIONS: Probiotic therapy with VSL#3 increases the total number of intestinal bacterial cells as well as the richness and diversity of the bacterial microbiota, especially the anaerobic flora. The diversity of the fungal flora is repressed. Restoration of the integrity of a "protective" intestinal mucosa related microbiota could therefore be a potential mechanism of probiotic bacteria in inflammatory barrier diseases of the lower gastrointestinal tract.

Adult↗