Prebiotics modulate the effects of antibiotics on gut microbial diversity and functioning in vitro

Intestinal bacteria carry out many fundamental roles, such as the fermentation of non-digestible dietary carbohydrates to produce short chain fatty acids (SCFAs), which can affect host energy levels and gut hormone regulation. Understanding how to manage this ecosystem to improve human health is an important but challenging goal. Antibiotics are the front line of defence against pathogens, but in turn they have adverse effects on indigenous microbial diversity and function. Here, we have investigated whether dietary supplementation—another method used to modulate gut composition and function—could be used to ameliorate the side effects of antibiotics. We perturbed gut bacterial communities with gentamicin and ampicillin in anaerobic batch cultures in vitro. Cultures were supplemented with either pectin (a non-fermentable fibre), inulin (a commonly used prebiotic that promotes the growth of beneficial bacteria) or neither. Although antibiotics often negated the beneficial effects of dietary supplementation, in some treatment combinations, notably ampicillin and inulin, dietary supplementation ameliorated the effects of antibiotics. There is therefore potential for using supplements to lessen the adverse effects of antibiotics. Further knowledge of such mechanisms could lead to better therapeutic manipulation of the human gut microbiota.

Effect of prebiotics on the fecal microbiota of elderly volunteers after dietary supplementation of Bacillus coagulans GBI-30, 6086

In advancing age, gut populations of beneficial microbes, notably Bifidobacterium spp., show a marked decline. This contributes to an environment less capable of maintaining homoeostasis. This in vitro investigation studied the possible synergistic effects of probiotic supplementation in modulating the gut microbiota enabling prebiotic therapy to in elderly persons. Single stage batch culture anaerobic fermenters were used and inoculated with fecal microbiota obtained from volunteers after taking a 28 day treatment of Bacillus coagulans GBI-30, 6086 (GanedenBC30 (BC30)) or a placebo. The response to prebiotic supplements fructooligosaccharides (FOS) and galactooligosaccharides (GOS) in the fermenters was assessed. Bacterial enumeration was carried out using fluorescent in situ hybridisation and organic acids measured by gas chromatography. Baseline populations of Faecalibacterium prausnitzii, Clostridium lituseburense and Bacillus spp. were significantly higher in those having consumed BC30 compared to the placebo. Both prebiotics increased populations of several purportedly beneficial bacterial groups in both sets of volunteers. Samples from volunteers having ingested the BC30 also increased populations of C. lituseburense, Eubacterium rectale and F. prausnitzii more so than in persons who had consumed the placebo, this also resulted in significantly higher concentrations of butyrate, acetate and propionate. This shows that consumption of BC30 and subsequent use of prebiotics resulted in elevated populations of beneficial genres of bacteria as well as organic acid production

Neonatal environment exerts a sustained influence on the development of the intestinal microbiota and metabolic phenotype

The postnatal environment, including factors such as weaning and acquisition of the gut microbiota, has been causally linked to the development of later immunological diseases such as allergy and autoimmunity, and has also been associated with a predisposition to metabolic disorders. We show that the very early-life environment influences the development of both the gut microbiota and host metabolic phenotype in a porcine model of human infants. Farmpiglets were nursed by their mothers for 1 day, before removal to highly controlled, individual isolators where they received formula milk until weaning at 21 days. The experiment was repeated, to create two batches, which differed only in minor environmental fluctuations during the first day. At day 1 after birth, metabolic profiling of serum by 1H nuclear magnetic resonance spectroscopy demonstrated significant, systemic, inter-batch variation which persisted until weaning. However, the urinary metabolic profiles demonstrated that significant inter-batch effects on 3-hydroxyisovalerate, trimethylamine-N-oxide and mannitol persisted beyond weaning to at least 35 days. Batch effects were linked to significant differences in the composition of colonic microbiota at 35 days, determined by 16 S pyrosequencing. Different weaning diets modulated both the microbiota and metabolic phenotype independently of the persistent batch effects. We demonstrate that the environment during the first day of life influences development of the microbiota and metabolic phenotype and thus should be taken into account when interrogating experimental outcomes. In addition, we suggest that intervention at this early time could provide ‘metabolic rescue’ for at-risk infants who have undergone aberrant patterns of initial intestinal colonisation.

The commensal infant gut meta-mobilome as a potential reservoir for persistent multidrug resistance integrons

Despite the accumulating knowledge on the development and establishment of the gut microbiota, its role as a reservoir for multidrug resistance is not well understood. This study investigated the prevalence and persistence patterns of an integrase gene (int1), used as a proxy for integrons (which often carry multiple antimicrobial resistance genes), in the fecal microbiota of 147 mothers and their children sampled longitudinally from birth to 2 years. The study showed the int1 gene was detected in 15% of the study population, and apparently more persistent than the microbial community structure itself. We found int1 to be persistent throughout the first two years of life, as well as between mothers and their 2-year-old children. Metagenome sequencing revealed integrons in the gut meta-mobilome that were associated with plasmids and multidrug resistance. In conclusion, the persistent nature of integrons in the infant gut microbiota makes it a potential reservoir of mobile multidrug resistance.

Maternal weaning modulates emotional behavior and regulates the gut-brain axis

Evidence shows that nutritional and environmental stress stimuli during postnatal period influence brain development and interactions between gut and brain. In this study we show that in rats, prevention of weaning from maternal milk results in depressive-like behavior, which is accompanied by changes in the gut bacteria and host metabolism. Depressive-like behavior was studied using the forced-swim test on postnatal day (PND) 25 in rats either weaned on PND 21, or left with their mother until PND 25 (non-weaned). Non-weaned rats showed an increased immobility time consistent with a depressive phenotype. Fluorescence in situ hybridization showed non-weaned rats to harbor significantly lowered Clostridium histolyticum bacterial groups but exhibit marked stress-induced increases. Metabonomic analysis of urine from these animals revealed significant differences in the metabolic profiles, with biochemical phenotypes indicative of depression in the non-weaned animals. In addition, non-weaned rats showed resistance to stress-induced modulation of oxytocin receptors in amygdala nuclei, which is indicative of passive stress-coping mechanism. We conclude that delaying weaning results in alterations to the gut microbiota and global metabolic profiles which may contribute to a depressive phenotype and raise the issue that mood disorders at early developmental ages may reflect interplay between mammalian host and resident bacteria.

Intestinal microbiota associated with differential feed conversion efficiency in chickens

Analysis of model systems, for example in mice, has shown that the microbiota in the gastrointestinal tract can play an important role in the efficiency of energy extraction from diets. The study reported here aimed to determine whether there are correlations between gastrointestinal tract microbiota population structure and energy use in chickens. Efficiency in converting food into muscle mass has a significant impact on the intensive animal production industries, where feed represents the major portion of production costs. Despite extensive breeding and selection efforts, there are still large differences in the growth performance of animals fed identical diets and reared under the same conditions. Variability in growth performance presents management difficulties and causes economic loss. An understanding of possible microbiota drivers of these differences has potentially important benefits for industry. In this study, differences in cecal and jejunal microbiota between broiler chickens with extreme feed conversion capabilities were analysed in order to identify candidate bacteria that may influence growth performance. The jejunal microbiota was largely dominated by lactobacilli (over 99% of jejunal sequences) and showed no difference between the birds with high and low feed conversion ratios. The cecal microbial community displayed higher diversity, and 24 unclassified bacterial species were found to be significantly (<0.05) differentially abundant between high and low performing birds. Such differentially abundant bacteria represent target populations that could potentially be modified with prebiotics and probiotics in order to improve animal growth performance.

Faecal microbiota of individuals with autism spectrum disorder

Many children with autistic spectrum disorders (ASDs) suffer from gastrointestinal problems such as diarrhoea, constipation and abdominal pain. Such symptoms may be due to a disruption of the indigenous gut microbiota promoting the overgrowth of potentially pathogenic micro-organisms. These observations have stimulated investigations into possible abnormalities of intestinal microbiota in autistic patients. The purpose of the present study was to determine if a relationship exists between ASD severity (mild – severe) and GI microbial populations. The faecal microbiota of 22 male and 6 female participants with ASDs (aged 7 ± 6 years) were analyzed by standard microbial culture methods and compared within-group (based on ASD severity) and with a standard laboratory reference range. Comparisons between children with mild ASD and those with moderate to severe ASD, as well as comparisons to a neurotypical control group previously reported, revealed that no significant differences appear to exist in the composition of the gut microbiota. Nevertheless, examination of each individual’s gut microbial composition showed 10 cases of unusual findings witch means 1out of 3 cases have unusual microbiota. Our data do not support consistent GI microbial abnormalities in ASD children, but the findings do suggest that aberrations may be found in a minority subset of ASD children. Further studies are required to determine the possible association between the microbiota and gastrointestinal dysfunctions in a subset of children with both ASD and gastro-intestinal problems.

The gut microbiome and diet in psychiatry: focus on depression

Purpose of review: With depressive disorders the leading source of disability globally, the identification of new targets for prevention and management is imperative. A rapidly emerging field of research suggests that the microbiome-gut-brain axis is of substantial relevance to mood and behaviour. Similarly, unhealthy diet has recently emerged as a significant correlate of and risk factor for depression. This review provides evidence for the gut microbiota as a key factor mediating the link between diet and depressive illness.

The gut microbiome and diet in psychiatry: focus on depression.

With depressive disorders the leading source of disability globally, the identification of new targets for prevention and management is imperative. A rapidly emerging field of research suggests that the microbiome-gut-brain axis is of substantial relevance to mood and behaviour. Similarly, unhealthy diet has recently emerged as a significant correlate of and risk factor for depression. This review provides evidence for the gut microbiota as a key factor mediating the link between diet and depressive illness.

Lactobacillus acidophilus CRL 1014 improved gut health in the SHIME® reactor

Background: How to maintain gut health is a goal for scientists throughout the world. Therefore, microbiota management models for testing probiotics, prebiotics, and synbiotics have been developed.Methods: The SHIME® model was used to study the effect of Lactobacillus acidophilus 1014 on the fermentation pattern of the colon microbiota. Initially, an inoculum prepared from human feces was introduced into the reactor vessels and stabilized over 2-wk using a culture medium. This stabilization period was followed by a 2-wk control period during which the microbiota was monitored. The microbiota was then subjected to a 4-wk treatment period by adding 5 mL of sterile peptone water with L. acidophilus CRL1014 at the concentration of 108 CFU/mL to vessel one (the stomach compartment). Plate counts, Denaturing Gradient Gel Electrophoresis (DGGE), short-chain fatty acid (SCFA) and ammonium analyses were carried out for monitoring of the microbial community from the colon compartments.Results: A significant increase (p < 0.01) in the Lactobacillus spp. and Bifidobacterium spp. populations was observed during the treatment period. The DGGE obtained showed changes in the lactobacilli community from the colon compartments of the SHIME® reactor. The (SCFA) concentration increased (p < 0.01) during the treatment period, due mainly to significant increased levels of acetic, butyric, and propionic acids. However, ammonium concentrations decreased during the same period (p < 0.01).Conclusions: This study showed the beneficial influence of L. acidophilus CRL 1014 on microbial metabolism and lactobacilli community composition for improving human health. © 2013 Sivieri et al.; licensee BioMed Central Ltd.

Estrutura, ultraestrutura e histoquímica do aparelho digestório do Prochilodus lineatus. Análise da diversidade da microbiota intestinal de Prochilodus lineatus e Pterygoplichthys anisitsi

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da restrição alimentar e do grupo genético sobre a microbiota do trato gastrintestinal, a expressão gênica hepática e a deposição de lipídeos na carcaça de frangos de corte

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

P-215-Quantitative variation of some gut bacteria in Crohn's disease can be related to the patient's gender

Background: Imbalance in bacterial species composition of the gut microbiota is one of the factors associated with the cause or complication of the symptoms of Crohn's disease (CD). This disequilibrium consists in the reduction of biodiversity, decrease of genus such as Bifidobacterium and elevation of species such as Escherichia coli. Human microbiota varies among subjects of a same population irrespective of their health condition and among individuals living in distinct geographic locations. In animal models, sex related differences could also be observed in gut bacterial species composition under some pathological conditions. Experiments conducted with mice have demonstrated that the manifestation of type 1 diabetes (T1D) could be under the influence of the animal sex and its serum level of testosterone, which in turn could be modulated by a particular gut microbiota. Considering the existence of similar features between T1D and CD, such as strong genetic component and malfunctioning of the immune system, we investigated whether differences could be observed in the gut microbiota dysbiosis of male and female CD patients. Methods: Fifty and 5 gut mucosal biopsies from 25 adult CD patients (11 males and 14 females) and 43 specimens of an equivalent clinical material from 22 control subjects (11 males and 11 females) were screened for bacterial biodiversity by analyzing sequences of 16SrDNA V6 region. A number of 2-3 samples each from distinct gut segments (from ileum to rectum) were taken from each subject. The 16SrDNA sequences were obtained by sequencing PCR amplicons of the corresponding gene in the Ion torrent PGM sequencer. Identification and classification of the bacterial groups followed the Ribosomal Database Project (RDP) website pipeline. The relationships of the bacterial taxa with each of the study parameters was performed by compiling the data in a MS Excel and the level of statistical significance determined by the Chi-square test. Results: A total of 3203 16SrDNA sequences were detected in the 98 biopsies samples, the majority of which matching Proteobacteria, Firmicutes, Bacterioidetes, and Actinobacteria. The percentage of DNA sequences for each of these phyla found in Male control subjects/Male CD patients was 40.5/33, 32.7/32.4, 20.8/24.5, and 4.4/4,4 for Proteobacteria, Firmicutes, Bacterioidetes, and Actinobacteria, respectively. In Female comparisons, these values were 35.6/42, 39.2/26.3, 19.8/23.3, 5.2/7. Both Male and Female CD patients presented higher numbers of sequences of Actinobacteria and Bacterioidetes than those of control subjects of the same gender. Case-control differences for Firmicutes could be observed only in female comparisons and, for Proteobacteria, although case-control differences were observed in both genders, the nature of difference was distinct, since while in CD female patients a higher number of sequences matching this phylum was detected, in males a reduced number was observed, in comparison with controls. The species responsible for the Proteobacteria variation in both gender was Escherichia coli. Conclusions: The data presented above suggest that any analysis of dysbiosis in CD must take in account the patient's gender, an observation particularly relevant for Escherichia coli, whose association with CD has been most intensively investigated and for which the present study shows a reverse quantitative variation regarding the patients' gender.