Prebiotics in healthy infants and children for prevention of acute infectious diseases: a systematic review and meta-analysis

Comparison of the relative impacts of acute consumption of an inulin-enriched diet, milk kefir or a commercial probiotic product on the human gut microbiome and metabolome

It has been established that the human gut microbiota is central to health, and, consequently, there has been a growing desire to positively modulate its composition and/or function through, for example, the use of fermented foods, prebiotics or probiotics. Here, we compare the relative impact of the daily consumption of an inulin-enriched diet (n = 10), a commercial probiotic-containing fermented milk product (FMP) (n = 10), or a traditional kefir FMP (n = 9), over a 28-day period on the gut microbiome and urine metabolome of healthy human adults. None of the treatments resulted in significant changes to clinical parameters or biomarkers tested. However, shotgun metagenomic analysis revealed that kefir consumption resulted in a significant change in taxonomy, in the form of an increased abundance of the sub-dominant FMP-associated species Lactococcus raffinolactis, which further corresponded to shifts in the urine metabolome. Overall, our results indicated that daily consumption of a single portion of kefir alone resulted in detectable changes to the gut microbiota and metabolome of consumers.

Alternative approaches to therapeutics and subtherapeutics for sustainable poultry production

The world population is growing rapidly and thus its demand for food is growing as well. To meet the demand of the ever-increasing number of consumers, the poultry industry and both of its main sectors-conventional and organic/cage-free farming-are expanding in parallel. Due to increasing demand of poultry products and higher mortality rate of chicks (an average 0.3% increase of mortality over last 5 yr), both conventional and organic poultry farming systems struggle with various issues; animal welfare, environmental sustainability, and antibiotic resistance of the prevailing zoonotic/enteric pathogens are common issues for conventional farming whereas slow growth rate, higher costs, inefficient land use, different diseases of the chicken, and cross-contamination with bacterial pathogens into the final products are the major issues for organic poultry farming. On top of these issues, the use of subtherapeutic antibiotics was recently banned in conventional farming systems and by definition the organic farming system cannot use the antibiotics/synthetic chemicals even for therapeutic use. In conventional farming system, use of therapeutic antibiotics may result in residuals antibiotics in the final products. As a result, sustainable alternatives are in demand to mitigate the prevailing issues for both conventional and organic farming. Potential alternatives may include bacteriophages, vaccination, probiotics, plant-derived prebiotics, and synbiotics. These alternatives have beneficial attributes and shortcomings of their use in both conventional and organic poultry production system. In this review, we'll discuss the scope of these potential alternatives as therapeutics and subtherapeutics in sustainable poultry production and ways to improve their efficacy.

Gastrointestinal Microbiome and Multiple Health Outcomes: Umbrella Review

In recent years, there has been growing concern about the impact of the gastrointestinal microbiome on human health outcomes. To clarify the evidence for a link between the gastrointestinal microbiome and a variety of health outcomes in humans, we conducted an all-encompassing review of meta-analyses and systematic reviews that included 195 meta-analyses containing 950 unique health outcomes. The gastrointestinal microbiome is related to mortality, gastrointestinal disease, immune and metabolic outcomes, neurological and psychiatric outcomes, maternal and infant outcomes, and other outcomes. Existing interventions for intestinal microbiota (such as probiotics, fecal microbiota transplant, etc.) are generally safe and beneficial to a variety of human health outcomes, but the quality of evidence is not high, and more detailed and well-designed randomized controlled trials are necessary.

The Protective Effects of Inulin-Type Fructans Against High-Fat/Sucrose Diet-Induced Gestational Diabetes Mice in Association With Gut Microbiota Regulation

Background

Inulin-type fructans (ITF) have been used as prebiotics to alleviate glucose and lipid metabolism disorders. However, few studies evaluated the microbial mechanism of ITF in improving maternal metabolic status during pregnancy.

Methods

C57BL/6J mice were fed a high-fat/sucrose diet (HFD) for 4 weeks before and throughout pregnancy to induce a model of gestational diabetes mellitus (GDM). Body weight, glycolipid metabolic parameters, and fecal short-chain fatty acids (SCFAs) were assessed in the experimental process. The effects of ITF on the fecal microbiota were analyzed by 16S rRNA gene amplicon sequencing.

Results

Pregnant HFD-fed mice displayed significant insulin resistance and dyslipidemia. ITF (3.33 g/kg/day) treatment improved glucose and lipid metabolism disorder parameters in HFD-induced GDM mice and alleviated fat accumulation and glucose intolerance. The alpha diversity of the gut microbial community was increased in ITF mice, while the beta diversity returned to the level of normal chow diet (NCD) mice. Interestingly, Verrucomicrobia, Bifidobacterium, and Akkermansia were obviously enriched, while Dubosiella was obviously lessened after inulin treatment. Further analysis indicated that Dubosiella was positively correlated with markers of glycolipid metabolism disorders, whereas the ITF-supplemented diet partially reversed the changes.

Conclusion

Our results suggest that the ITF treatment may alleviate glucose and lipid metabolism disorders with the mediation of gut microbiota.

Gut-lung cross talk in COVID-19 pathology and fatality rate

Coronavirus disease 2019 (COVID-19) is the leading pandemic facing the world in 2019/2020; it is caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which necessitates clear understanding of the infectious agent. The virus manifests aggressive behavior with severe clinical presentation and high mortality rate, especially among the elderly and patients living with chronic diseases. In the recent years, the role of gut microbiota, in health and disease, has been progressively studied and highlighted. It is through gut microbiota-organ bidirectional pathways, such as gut-brain axis, gut-liver axis, and gut-lung axis, that the role of gut microbiota in prompting lung disease, among other diseases, has been proposed and accepted. It is also known that respiratory viral infections, such as COVID-19, induce alterations in the gut microbiota, which can influence immunity. Based on the fact that gut microbiota diversity is decreased in old age and in patients with certain chronic diseases, which constitute two of the primary fatality groups in COVID-19 infections, it can be assumed that the gut microbiota may play a role in COVID-19 pathology and fatality rate. Improving gut microbiota diversity through personalized nutrition and supplementation with prebiotics/probiotics will mend the immunity of the body and hence could be one of the prophylactic strategies by which the impact of COVID-19 can be minimized in the elderly and immunocompromised patients. In this chapter, the role of dysbiosis in COVID-19 will be clarified and the possibility of using co-supplementation of personalized prebiotics/probiotics with current therapies will be discussed.

Non-antibiotic interventions for prevention of urinary tract infections in children: a systematic review and meta-analysis of randomized controlled trials

A considerable proportion of children experience a recurrence of urinary tract infection (UTI) following the first episode. While low-dose antibiotic prophylaxis has been the mainstay for the prevention of UTI, recent evidence raised concerns over their efficacy and safety. Hence, we aim to systematically synthesize evidence on the efficacy and safety of non-antibiotic prophylactic interventions for UTI. Using keywords related to study population (children) and intervention (non-antibiotic), we searched CENTRAL, Embase, PubMed, and Web of Science for randomized controlled trials (RCTs) published until August 2020. RCTs comparing any non-antibiotic interventions with placebo/antibiotics for prevention of UTIs in children were considered eligible. We used a random-effect model to provide pooled estimates. Sixteen trials evaluating 1426 participants were included. Cranberry was as effective as antibiotic prophylaxis (RR: 0.92; 95% CI: 0.56-1.50) but better than placebo/no therapy (RR: 0.48; 95% CI: 0.28-0.80) in reducing UTI recurrence. Probiotic therapy was more effective in reducing UTI recurrence (RR: 0.52; 95% CI: 0.29-0.94) when compared with placebo. While probiotic therapy was not better than antibiotics prophylaxis in preventing UTI (RR: 0.82; 95% CI: 0.56-1.21), they have a lower risk of antibiotic resistance (RR: 0.38; 95% CI: 0.21-0.69).Conclusion: Cranberry products and probiotics are the two non-antibiotic interventions that have been chiefly evaluated, reduce the risk of UTI recurrence when compared with placebo in children with a normal urinary tract. The findings from this systematic review suggest that while cranberry and probiotics may be used, there is a definite need to identify better and more acceptable non-antibiotic interventions. What is Known: • Efficacy of the low-dose antibiotic is controversial in preventing UTI and it is associated with increase in the risk of antimicrobial resistance. • Non-antibiotic interventions such as cranberry products are effective in preventing UTI recurrence in adults. What is New: • Cranberry products are effective in reducing the recurrence of UTI in children with normal urinary tract. • Low-quality evidence suggests that probiotics can be a potential prophylactic measure to reduce recurrence of UTI in the pediatric population.

Long-Term Safety and Efficacy of Prebiotic Enriched Infant Formula-A Randomized Controlled Trial

The present study aims to evaluate the effects of an infant formula supplemented with a mixture of prebiotic short and long chain inulin-type oligosaccharides on health outcomes, safety and tolerance, as well as on fecal microbiota composition during the first year of life. In a prospective, multicenter, randomized, double-blind study, n = 160 healthy term infants under 4 months of age were randomized to receive either an infant formula enriched with 0.8 g/dL of Orafti^®Synergy1 or an unsupplemented control formula until the age of 12 months. Growth, fever (>38 °C) and infections were regularly followed up by a pediatrician. Digestive symptoms, stool consistency as well as crying and sleeping patterns were recorded during one week each study month. Fecal microbiota and immunological biomarkers were determined from a subgroup of infants after 2, 6 and 12 months of life. The intention to treat (ITT) population consisted of n = 149 infants. Both formulae were well tolerated. Mean duration of infections was significantly lower in the prebiotic fed infants (p < 0.05). The prebiotic group showed higher Bifidobacterium counts at month 6 (p = 0.006), and higher proportions of Bifidobacterium in relation to total bacteria at month 2 and 6 (p = 0.042 and p = 0.013, respectively). Stools of infants receiving the prebiotic formula were softer (p < 0.05). Orafti^®Synergy1 tended to beneficially impact total daily amount of crying (p = 0.0594). Supplementation with inulin-type prebiotic oligosaccharides during the first year of life beneficially modulates the infant gut microbiota towards higher Bifidobacterium levels at the first 6 months of life, and is associated with reduced duration of infections.

The use of fecal microbiota transplant in sepsis

Sepsis is defined as a dysregulated inflammatory response, which ultimately results from a perturbed interaction of both an altered immune system and the biomass and virulence of involved pathogens.  This response has been tied to the intestinal microbiota, as the microbiota and its associated metabolites play an essential role in regulating the host immune response to infection.  In turn, critical illness as well as necessary health care treatments result in a collapse of the intestinal microbiota diversity and a subsequent loss of health-promoting short chain fatty acids, such as butyrate, leading to the development of a maladaptive pathobiome.  These perturbations of the microbiota contribute to the dysregulated immune response and organ failure associated with sepsis.  Several case series have reported the ability of fecal microbiota transplant (FMT) to restore the host immune response and aid in recovery of septic patients.  Additionally, animal studies have revealed the mechanism of FMT rescue in sepsis is likely related to the ability of FMT to restore butyrate producing bacteria and alter the innate immune response aiding in pathogen clearance.  However, several studies have reported lethal complications associated with FMT, including bacteremia.  Therefore, FMT in the treatment of sepsis is and should remain investigational until a more detailed mechanism of how FMT restores the host immune response in sepsis is determined, allowing for the development of more fine-tuned microbiota therapies.

Synopsis

Akute entzündliche Reaktionen bzw. der akute Infekt mit Restitutio ad integrum laufen in einer perfekt modulierten Kaskade ab, bei dem eine akute inflammatorische Einleitungsphase von einer antiinflammatorischen Phase und einer Entzündungsauflösungsphase abgelöst werden.

Establishing What Constitutes a Healthy Human Gut Microbiome: State of the Science, Regulatory Considerations, and Future Directions

On December 17, 2018, the North American branch of the International Life Sciences Institute (ILSI North America) convened a workshop "Can We Begin to Define a Healthy Gut Microbiome Through Quantifiable Characteristics?" with >40 invited academic, government, and industry experts in Washington, DC. The workshop objectives were to 1) develop a collective expert assessment of the state of the evidence on the human gut microbiome and associated human health benefits, 2) see if there was sufficient evidence to establish measurable gut microbiome characteristics that could serve as indicators of "health," 3) identify short- and long-term research needs to fully characterize healthy gut microbiome-host relationships, and 4) publish the findings. Conclusions were as follows: 1) mechanistic links of specific changes in gut microbiome structure with function or markers of human health are not yet established; 2) it is not established if dysbiosis is a cause, consequence, or both of changes in human gut epithelial function and disease; 3) microbiome communities are highly individualized, show a high degree of interindividual variation to perturbation, and tend to be stable over years; 4) the complexity of microbiome-host interactions requires a comprehensive, multidisciplinary research agenda to elucidate relationships between gut microbiome and host health; 5) biomarkers and/or surrogate indicators of host function and pathogenic processes based on the microbiome need to be determined and validated, along with normal ranges, using approaches similar to those used to establish biomarkers and/or surrogate indicators based on host metabolic phenotypes; 6) future studies measuring responses to an exposure or intervention need to combine validated microbiome-related biomarkers and/or surrogate indicators with multiomics characterization of the microbiome; and 7) because static genetic sampling misses important short- and long-term microbiome-related dynamic changes to host health, future studies must be powered to account for inter- and intraindividual variation and should use repeated measures within individuals.

The Long-Term Effects of Dietary Nutrient Intakes during the First 2 Years of Life in Healthy Infants from Developed Countries: An Umbrella Review

The role of both qualitative and quantitative early nutrient intakes on later health has been suggested for decades and supported by observational studies on humans, mainly preterm and low-birth-weight infants, and animal models. However, to date, no comprehensive review has been conducted to evaluate the full impact of nutritional variables on healthy full-term infants. This umbrella review considers meta-analyses and systematic reviews on the health effects of different nutritional exposures or interventions in the first 2 y of life of healthy full-term infants in developed countries. The systematic reviews and meta-analyses published by March 2018 in MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews were included. The following outcomes were considered: growth and obesity, cardiovascular disease, neurodevelopment, allergy and autoimmunity, infections, and malignancy. Breastfeeding and complementary feeding were considered separately and analyzed by means of their differences in delivering heterogeneous food-related variables. The resulting data on the long-term effect of early nutritional differences in healthy full-term infants were found to be inconclusive. Only breastfeeding has a beneficial effect, which is nevertheless slight and limited to just a few outcome measures, whereas the type and duration required to be effective are still unclear. As regards the complementary feeding period, no clear effects of different dietary interventions emerge in terms of health outcomes. Available evidence on the health effects of differences in early nutrition in healthy full-term infants still remains largely inconclusive.

Dietary Factors in Prevention of Pediatric Escherichia coli Infection: A Model Using Domestic Piglets

Enterotoxigenic Escherichia coli (ETEC) is the major etiological agent causing acute watery diarrhea that is most frequently seen in young children in lower-income countries. The duration of diarrheal symptom may be shortened by antibiotic treatment, but ETEC is relative refractory to common antibiotics. Burgeoning evidence suggests bioactive components that naturally occur in human milk (e.g., lysozyme and oligosaccharides) and plants (e.g., nondigestible carbohydrates and phytochemicals) contain antimicrobial functions are promising preventive measures to control ETEC infection. Although the exact protective mechanisms may vary for each compound and are still not completely understood, they generally act to (1) competitively inhibit the binding of pathogenic bacteria and toxins to gut epithelium; (2) directly kill pathogens; and (3) stimulate and/or enhance host mucosal and systemic immune defense against pathogenic microorganisms. An appropriate ETEC-challenge animal model is critical to evaluate the effect and unveil the mechanism of bioactive compounds in prevention of enteric infection. Despite wide application in biomedical research, rodents do not usually manifest typical clinical signs of enteric infections. The remarkable differences in digestive physiology, immune response, and gut microbiota between rodents and human beings necessitate the use of alternative animal models. Pigs are closely related to humans in terms of genomes, physiology, anatomy of gastrointestinal tracts, digestive enzymes, components of immune system, and gut microbiota. Like human infants and young children, nursing and nursery piglets are more susceptible to ETEC infection and reproduce the clinical signs as observed in humans. Hence, the ETEC-challenge piglet represents a valuable translational model to study pathogenesis and evaluate dietary factors (e.g., milk bioactive compounds, nondigestible carbohydrates, and phytochemicals) as preventive measures for ETEC infection in pediatrics.

Effects of prebiotics on sepsis, necrotizing enterocolitis, mortality, feeding intolerance, time to full enteral feeding, length of hospital stay, and stool frequency in preterm infants: a meta-analysis

BACKGROUND/OBJECTIVES

Prebiotics are increasingly recognized as an effective measure to promote health and prevent adverse health outcomes in preterm infants. We aimed to systematically review the randomized controlled trials (RCTs) in this area.

SUBJECTS/METHODS

Relevant studies from January 2000 to June 2018 were searched and selected from PubMed, Medline, Scopus, and the Cochrane Library. RCTs were included if they involved preterm infant participants, included a prebiotic intervention group, measured incidence of sepsis, feeding intolerance, mortality, time to full enteral feeding, necrotizing enterocolitis (NEC), length of hospital stay, and stool frequency as outcomes.

RESULTS

Eighteen RCTs (n = 1322) were included in the final meta-analysis. Participants who took prebiotics showed significant decreases in the incidence of sepsis (with a risk ratio (RR) of 0.64, 95% CI: 0.51, 0.78), mortality (RR = 0.58. 95% CI: 0.36, 0.94), length of hospital stay (mean difference (MD): -5.18, 95% CI: -8.94, -1.11), and time to full enteral feeding (MD: -0.99, 95% CI: -1.15, 0.83). The pooled effects showed no significant differences between intervention and control groups in relation to the morbidity rate of NEC (RR = 0.79, 95% CI: 0.44, 1.44) or feeding intolerance (RR = 0.87, 95% CI: 0.52, 1.45).

CONCLUSIONS

The results showed that the use of prebiotics with preterm infants is safe and can decrease the incidence of sepsis, mortality, length of hospital stay, and time to full enteral feeding but not NEC.

The role of the microbiota in infectious diseases

The human body is colonized by a diverse community of microorganisms collectively referred to as the microbiota. Here, we describe how the human microbiota influences susceptibility to infectious diseases using examples from the respiratory, gastrointestinal and female reproductive tract. We will discuss how interactions between the host, the indigenous microbiota and non-native microorganisms, including bacteria, viruses and fungi, can alter the outcome of infections. This Review Article will highlight the complex mechanisms by which the microbiota mediates colonization resistance, both directly and indirectly, against infectious agents. Strategies for the therapeutic modulation of the microbiota to prevent or treat infectious diseases will be discussed, and we will review potential therapies that directly target the microbiota, including prebiotics, probiotics, synbiotics and faecal microbiota transplantation.

In Vitro Fermentation of Selected Prebiotics and Their Effects on the Composition and Activity of the Adult Gut Microbiota

Recently, the concept of prebiotics has been revisited to expand beyond non-digestible oligosaccharides, and the requirements for selective stimulation were extended to include microbial groups other than, and additional to, bifidobacteria and lactobacilli. Here, the gut microbiota-modulating effects of well-known and novel prebiotics were studied. An in vitro fermentation screening platform (i-screen) was inoculated with adult fecal microbiota, exposed to different dietary fibers that had a range of concentrations (inulin, alpha-linked galacto-oligosaccharides (alpha-GOS), beta-linked GOS, xylo-oligosaccharides (XOS) from corn cobs and high-fiber sugar cane, and beta-glucan from oats), and compared to a positive fructo-oligosaccharide (FOS) control and a negative control (no fiber addition). All dietary fibers displayed prebiotic activity, with beta-glucan showing more distinct effects on the microbial composition and metabolism compared to the other fibers. Beta-glucan induced the growth of Prevotella and Roseburia with a concomitant increase in propionate production. Inulin and both forms of GOS and XOS had a strong bifidogenic effect on the microbial composition. A dose-response effect was observed for butyrate when exposed to beta-glucan and inulin. The findings of this study support the potential for alpha-GOS, XOS, and oat beta-glucan to serve as novel prebiotics, due to their association with the positive shifts in microbiome composition and short-chain fatty acid production that point to potential health benefits.

Inulin-Type Fructan Supplementation of 3- to 6-Year-Old Children Is Associated with Higher Fecal Bifidobacterium Concentrations and Fewer Febrile Episodes Requiring Medical Attention

Background

Inulin-type fructans used in formula have been shown to promote microbiota composition and stool consistency closer to those of breastfed infants and to have beneficial effects on fever occurrence, diarrhea, and incidence of infections requiring antibiotic treatment in infants.

Objectives

The primary study aim was to explore whether prophylactic supplementation with prebiotic fructans is able to influence the frequency of infectious diseases in kindergarten children during a winter period. A secondary objective was to ascertain the effect on the intestinal microbiota.

Methods

142 boys and 128 girls aged 3-6 y were randomly allocated to consume 6 g/d fructans or maltodextrin for 24 wk. At baseline, stool samples were collected for microbiota analysis and anthropometric measurements were made. During the intervention period diagnoses were recorded by physicians, whereas disease symptoms, kindergarten absenteeism, dietary habits, and stool consistency were recorded by parents. Baseline measurements were repeated at wk 24.

Results

In total 219 children finished the study. Both the relative abundance of Bifidobacterium (P < 0.001) and that of Lactobacillus (P = 0.014) were 19.9% and 7.8% higher, respectively, post data normalization, in stool samples of children receiving fructans as compared with those of controls at wk 24. This was accompanied by significantly softer stools within the normal range in the prebiotic group from wk 12 onwards. The incidence of febrile episodes requiring medical attention [0.65 ± 1.09 compared with 0.9 ± 1.11 infections/(24 wk × child), P = 0.04] and that of sinusitis (0.01 ± 0.1 compared with 0.06 ± 0.25, P = 0.03) were significantly lower in the prebiotic group. The number of infectious episodes and their duration reported by parents did not differ significantly between the 2 intervention groups.

Conclusions

Prebiotic supplementation modified the composition of the intestinal microbiota and resulted in softer stools in kindergarten-aged children. The reduction in febrile episodes requiring medical attention supports the concept of further studies on prebiotics in young children. This trial was registered at clinicaltrials.gov as NCT03241355.

The efficacy of probiotics in prevention of urinary tract infection in children: A systematic review and meta-analysis

BACKGROUND

A consensus has not been reached yet about the efficacy of probiotics in reducing the incidence of urinary tract infections (UTIs) in children. This systematic review and meta-analysis was designed to assess the efficacy of probiotics in prevention UTI in children.

METHODS

The present study was designed based on guidelines for systematic reviews of clinical trials. Two independent reviewers performed an extensive search in the Medline, Embase, Web of Science and Scopus electronic databases up to the end of 2016. The summery of eligible studies was assessed independently by two reviewers and recorded in the data extraction form. Finally, a pooled relative risk (RR) was reported with a 95% confidence interval (95% CI).

RESULTS

Data from 10 studies were entered in the present meta-analysis. Probiotic therapy did not have any beneficial effect on the incidence of UTI (RR = 0.94; 95% CI 0.85-1.03; p = 0.19) and its recurrence (RR = 0.93; 95% CI 0.85-1.02; p = 0.14). Subgroup analyses showed that probiotics as monotherapy do not have any beneficial effects on prevention of UTI (RR = 0.96; 95% CI 0.89-1.04; p = 0.31). However, the incidence of UTI is reduced if probiotics are used as adjuvant therapy to antibiotics (RR = 0.92; 95% CI 0.85-0.99; p = 0.02).

CONCLUSION

The present meta-analysis showed that probiotics did not have a beneficial effect in reducing the incidence or recurrence of UTI. Only a moderate efficacy was seen when a probiotic was used as adjuvant therapy to antibiotics.

The gut and oral microbiome in HIV disease: a workshop report

Recent years have seen a massive expansion in our understanding of how we interact with our microbial colonists. The development of new, rapid sequencing techniques such as pyrosequencing and other next-generation sequencing systems have enabled us to begin to characterise the constituents of our diverse microbial communities, revealing the astonishing genetic richness that is our microbiome. Despite this, our ignorance of how these communities change over the course of an HIV infection is profound. Whilst some steps have been made to characterise the HIV microbiome at selected sites, these reports are still limited and much remains to be done. It has become apparent, however, that host-microbiota interactions are perturbed during HIV infections, with microbial translocation of potential pathogens linked to a variety of different HIV complications, including more rapid progression of disease. The use of probiotics and prebiotics has been investigated as treatments to alleviate symptoms for a variety of conditions, and is now being proposed for the treatment of symptoms associated with HIV. However, this is a new area of investigations and many questions remain unanswered. What we know about both of these topics is a drop in the ocean compared with what we need to know. In this article, we report on a workshop where these two major under-investigated research areas were presented, and future directions explored and discussed.

Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics

In December 2016, a panel of experts in microbiology, nutrition and clinical research was convened by the International Scientific Association for Probiotics and Prebiotics to review the definition and scope of prebiotics. Consistent with the original embodiment of prebiotics, but aware of the latest scientific and clinical developments, the panel updated the definition of a prebiotic: a substrate that is selectively utilized by host microorganisms conferring a health benefit. This definition expands the concept of prebiotics to possibly include non-carbohydrate substances, applications to body sites other than the gastrointestinal tract, and diverse categories other than food. The requirement for selective microbiota-mediated mechanisms was retained. Beneficial health effects must be documented for a substance to be considered a prebiotic. The consensus definition applies also to prebiotics for use by animals, in which microbiota-focused strategies to maintain health and prevent disease is as relevant as for humans. Ultimately, the goal of this Consensus Statement is to engender appropriate use of the term 'prebiotic' by relevant stakeholders so that consistency and clarity can be achieved in research reports, product marketing and regulatory oversight of the category. To this end, we have reviewed several aspects of prebiotic science including its development, health benefits and legislation.

Pectin-Derived Acidic Oligosaccharides Improve the Outcome of Pseudomonas aeruginosa Lung Infection in C57BL/6 Mice

The administration of prebiotics as oligosaccharides (OS), by acting on intestinal microbiota, could modulate the immune and inflammatory response and represent a new strategy to improve the outcome of bacterial infection. The aim of this study was to determine whether pectin-derived acidic oligosaccharides (pAOS) could modulate the outcome of pulmonary P. aeruginosa (PA) infection in C57BL/6 mice, which develop a Th1 response to PA lung infection. Mice were randomized for 5 weeks to consume a control or a 5% pAOS diet and chronically infected by PA. Resistance to a second PA infection was also analyzed by reinfecting the surviving mice 2 weeks after the first infection. Compared with control mice, mice fed pAOS had reduced mortality (P<0.05). This improvement correlated with a better control of the inflammatory response with a lower neutrophil count on day 1 (P<0.05), a sustained neutrophil and macrophage recruitment on days 2 and 3 (P<0.01) a greater and sustained IL-10 release in lung (P<0.05) and a reduction of the Th1 response and M1 activation with a lower IFN-γ/IL-4 (P<0.01) and nos2/arg1 (P<0.05) ratios. These results coincided with a modulation of the intestinal microbiota as shown by an increased butyric acid concentration in feces (P<0.05). Moreover, pAOS decreased the bacterial load (P<0.01) in mice reinfected 2 weeks after the first infection, suggesting that pAOS could reduce pulmonary exacerbations. In conclusion, pAOS improved the outcome of PA infection in C57BL/6 mice by modulating the intestinal microbiota and the inflammatory and immune responses.

The Microbiome and Sustainable Healthcare

Increasing prevalences, morbidity, premature mortality and medical needs associated with non-communicable diseases and conditions (NCDs) have reached epidemic proportions and placed a major drain on healthcare systems and global economies. Added to this are the challenges presented by overuse of antibiotics and increased antibiotic resistance. Solutions are needed that can address the challenges of NCDs and increasing antibiotic resistance, maximize preventative measures, and balance healthcare needs with available services and economic realities. Microbiome management including microbiota seeding, feeding, and rebiosis appears likely to be a core component of a path toward sustainable healthcare. Recent findings indicate that: (1) humans are mostly microbial (in terms of numbers of cells and genes); (2) immune dysfunction and misregulated inflammation are pivotal in the majority of NCDs; (3) microbiome status affects early immune education and risk of NCDs, and (4) microbiome status affects the risk of certain infections. Management of the microbiome to reduce later-life health risk and/or to treat emerging NCDs, to spare antibiotic use and to reduce the risk of recurrent infections may provide a more effective healthcare strategy across the life course particularly when a personalized medicine approach is considered. This review will examine the potential for microbiome management to contribute to sustainable healthcare.

Gut microbiota: a source of novel tools to reduce the risk of human disease?

Modern civilization is faced with a progressive increase in immune-mediated or inflammatory health problems such as allergic disease, autoimmune disorders, and obesity. An extended version of the hygiene hypothesis has been introduced to emphasize the intimate interrelationship among diet, the immune system, microbiome, and origins of human disease: the modern infant, particularly when delivered by cesarean section and without the recommended exclusive breastfeeding, may lack sufficient stimulation of the mucosal immune system to generate a tolerogenic immune milieu and instead be prone to develop chronic inflammatory conditions. These deviations may take the form of allergic or autoimmune disease, or predispose the child to higher weight gain and obesity. Moreover, evidence supports the role of first microbial contacts in promoting and maintaining a balanced immune response in early life and recent findings suggest that microbial contact begins prior to birth and is shaped by the maternal microbiota. Maternal microbiota may prove to be a safe and effective target for interventions decreasing the risk of allergic and noncommunicable diseases in future generations. These results support the hypothesis that targeting early interaction with microbes might offer an applicable strategy to prevent disease.

The human intestinal microbiome at extreme ages of life. Dietary intervention as a way to counteract alterations

The intestinal microbiome is defined as the assembly of genomes from microorganisms inhabiting the gut. This microbial ecosystem regulates important functions of the host and its correct composition and functionality is essential for a “healthy status.” Metagenomic studies have highlighted variations of the intestinal microbiota as a function of age and diet. Colonization of the infant gut starts at birth and is influenced by feeding habits (formula vs. breast-feeding), birth mode and antibiotic exposure. The intestinal microbiota of full-term vaginally delivered breast-fed infants is considered the gold-standard, representing the reference for studies of alterations in other pediatric populations. At 2–3 years of age, the intestinal microbiota reaches a composition similar to adults, remaining without noticeable variations until senescence, when microbial instability and changes reappear. Here we summarize the current knowledge on intestinal microbiota alterations at extreme stages of life and tools for designing differentiated nutritional strategies by the use of probiotics, prebiotics and specific nutrients in order to restore a balanced microbiota and to improve immune and nutritional status.