Early colonization with a group of Lactobacilli decreases the risk for allergy at five years of age despite allergic heredity

Gut microbiota dysbiosis and its impact on asthma and other lung diseases: potential therapeutic approaches

The emerging field of gut-lung axis research has revealed a complex interplay between the gut microbiota and respiratory health, particularly in asthma. This review comprehensively explored the intricate relationship between these two systems, focusing on their influence on immune responses, inflammation, and the pathogenesis of respiratory diseases. Recent studies have demonstrated that gut microbiota dysbiosis can contribute to asthma onset and exacerbation, prompting investigations into therapeutic strategies to correct this imbalance. Probiotics and prebiotics, known for their ability to modulate gut microbial compositions, were discussed as potential interventions to restore immune homeostasis. The impact of antibiotics and metabolites, including short-chain fatty acids produced by the gut microbiota, on immune regulation was examined. Fecal microbiota transplantation has shown promise in various diseases, but its role in respiratory disorders is not established. Innovative approaches, including mucus transplants, inhaled probiotics, and microencapsulation strategies, have been proposed as novel therapeutic avenues. Despite challenges, including the sophisticated adaptability of microbial communities and the need for mechanistic clarity, the potential for microbiota-based interventions is considerable. Collaboration between researchers, clinicians, and other experts is essential to unravel the complexities of the gut-lung axis, paving a way for innovative strategies that could transform the management of respiratory diseases.

Association Between Gut and Nasal Microbiota and Allergic Rhinitis: A Systematic Review

Allergic rhinitis is a chronic non-infectious inflammation of the nasal mucosa mediated by specific IgE. Recently, the human microbiome has drawn broad interest as a potential new target for treating this condition. This paper succinctly summarizes the main findings of 17 eligible studies published by February 2024, involving 1044 allergic rhinitis patients and 954 healthy controls from 5 countries. These studies examine differences in the human microbiome across important mucosal interfaces, including the nasal and intestinal areas, between patients and controls. Overall, findings suggest variations in the gut microbiota between allergic rhinitis patients and healthy individuals, although the specific bacterial taxa that significantly changed were not always consistent across studies. Due to the limited scope of existing research and patient coverage, the relationship between the nasal microbiome and allergic rhinitis remains inconclusive. The article discusses the potential immune-regulating role of the gut microbiome in allergic rhinitis. Further well-designed clinical trials with large-scale recruitment of allergic rhinitis patients are encouraged.

The Role of Biodiversity in the Development of Asthma and Allergic Sensitization: A State-of-the-Science Review

BACKGROUND

Changes in land use and climate change have been reported to reduce biodiversity of both the environment and human microbiota. These reductions in biodiversity may lead to inadequate and unbalanced stimulation of immunoregulatory circuits and, ultimately, to clinical diseases, such as asthma and allergies.

OBJECTIVE

We summarized available empirical evidence on the role of inner (gut, skin, and airways) and outer (air, soil, natural waters, plants, and animals) layers of biodiversity in the development of asthma, wheezing, and allergic sensitization.

METHODS

We conducted a systematic search in SciVerse Scopus, PubMed MEDLINE, and Web of Science up to 5 March 2024 to identify relevant human studies assessing the relationships between inner and outer layers of biodiversity and the risk of asthma, wheezing, or allergic sensitization. The protocol was registered in PROSPERO (CRD42022381725).

RESULTS

A total of 2,419 studies were screened and, after exclusions and a full-text review of 447 studies, 82 studies were included in the comprehensive, final review. Twenty-nine studies reported a protective effect of outer layer biodiversity in the development of asthma, wheezing, or allergic sensitization. There were also 16 studies suggesting an effect of outer layer biodiversity on increasing asthma, wheezing, or allergic sensitization. However, there was no clear evidence on the role of inner layer biodiversity in the development of asthma, wheezing, and allergic sensitization (13 studies reported a protective effect and 15 reported evidence of an increased risk).

CONCLUSIONS

Based on the reviewed literature, a future systematic review could focus more specifically on outer layer biodiversity and asthma. It is unlikely that association with inner layer biodiversity would have enough evidence for systematic review. Based on this comprehensive review, there is a need for population-based longitudinal studies to identify critical periods of exposure in the life course into adulthood and to better understand mechanisms linking environmental exposures and changes in microbiome composition, diversity, and/or function to development of asthma and allergic sensitization. https://doi.org/10.1289/EHP13948.

Microbes little helpers and suppliers for therapeutic asthma approaches

Bronchial asthma is a prevalent and increasingly chronic inflammatory lung disease affecting over 300 million people globally. Initially considered an allergic disorder driven by mast cells and eosinophils, asthma is now recognized as a complex syndrome with various clinical phenotypes and immunological endotypes. These encompass type 2 inflammatory endotypes characterized by interleukin (IL)-4, IL-5, and IL-13 dominance, alongside others featuring mixed or non-eosinophilic inflammation. Therapeutic success varies significantly based on asthma phenotypes, with inhaled corticosteroids and beta-2 agonists effective for milder forms, but limited in severe cases. Novel antibody-based therapies have shown promise, primarily for severe allergic and type 2-high asthma. To address this gap, novel treatment strategies are essential for better control of asthma pathology, prevention, and exacerbation reduction. One promising approach involves stimulating endogenous anti-inflammatory responses through regulatory T cells (Tregs). Tregs play a vital role in maintaining immune homeostasis, preventing autoimmunity, and mitigating excessive inflammation after pathogenic encounters. Tregs have demonstrated their ability to control both type 2-high and type 2-low inflammation in murine models and dampen human cell-dependent allergic airway inflammation. Furthermore, microbes, typically associated with disease development, have shown immune-dampening properties that could be harnessed for therapeutic benefits. Both commensal microbiota and pathogenic microbes have demonstrated potential in bacterial-host interactions for therapeutic purposes. This review explores microbe-associated approaches as potential treatments for inflammatory diseases, shedding light on current and future therapeutics.

Dietary Protective Potential of Fucoxanthin as an Active Food Component on Neurological Disorders

The prevalence of neurodegenerative, cerebrovascular, and psychiatric diseases and other neurological disorders has increased dramatically worldwide. Fucoxanthin is an algal pigment with many biological functions, and there is rising evidence that fucoxanthin plays a preventive and therapeutic role in neurological disorders. This review focuses on the metabolism, bioavailability, and blood-brain barrier penetration of fucoxanthin. Furthermore, the neuroprotective potential of fucoxanthin in neurodegenerative diseases, cerebrovascular diseases, and psychiatric diseases as well as other neurological disorders such as epilepsy, neuropathic pain, and brain tumors by acting on multiple targets will be summarized. The multiple targets include regulating apoptosis, reducing oxidative stress, activating the autophagy pathway, inhibiting Aβ aggregation, improving dopamine secretion, reducing α-synuclein aggregation, attenuating neuroinflammation, modulating gut microbiota, and activating brain-derived neurotrophic factor, etc. Additionally, we look forward to brain-targeted oral transport systems due to the low bioavailability and blood-brain barrier permeability of fucoxanthin. We also propose exploring the systemic mechanisms of fucoxanthin metabolism and transport through the gut-brain process and envision new therapeutic targets for fucoxanthin to act on the central nervous system. Finally, we propose dietary fucoxanthin delivery interventions to achieve preventive effects on neurological disorders. This review provides a reference for the application of fucoxanthin in the neural field.

Bacillus subtilis Provides Long-Term Protection in a Murine Model of Allergic Lung Disease by Influencing Bacterial Composition

Probiotics are an attractive target for reducing the incidence of allergic disease. Bacillus subtilis is a gut-associated probiotic bacteria that can suppress allergic lung disease; however, it is not clear for how long this protection lasts. We exposed C57Bl/6 mice to B. subtilis via oral gavage and challenged them with intranasal house-dust mite for up to 8 weeks. We found that B. subtilis treatment was able to provide protection from eosinophil infiltration of the airways for 3 weeks. This loss of protection correlated with an increase in the eosinophil chemoattractant CCL24. Additionally, we demonstrate that B. subtilis treatment altered the bacterial composition by increasing the phylum Bacteroidetes and Verrucomicorbiota. The phylum Verrucomicorbiota was reduced in B. subtilis-treated mice at 8 weeks when protection was lost. These results support B. subtilis as a prophylactic for preventing the production of allergic lung disease and highlights that protection can last up to 3 weeks. This work also expands our understanding of how B. subtilis mediates protection and that in addition to modifying the immune system it is also altering the host microbiota.

Contribution of Lactobacilli on Intestinal Mucosal Barrier and Diseases: Perspectives and Challenges of Lactobacillus casei

The intestine barrier, the front line of normal body defense, relies on its structural integrity, microbial composition and barrier immunity. The intestinal mucosal surface is continuously exposed to a complex and dynamic community of microorganisms. Although it occupies a relatively small proportion of the intestinal microbiota, Lactobacilli has been discovered to have a significant impact on the intestine tract in previous studies. It is undeniable that some Lactobacillus strains present probiotic properties through maintaining the micro-ecological balance via different mechanisms, such as mucosal barrier function and barrier immunity, to prevent infection and even to solve some neurology issues by microbiota-gut-brain/liver/lung axis communication. Notably, not only living cells but also Lactobacillus derivatives (postbiotics: soluble secreted products and para-probiotics: cell structural components) may exert antipathogenic effects and beneficial functions for the gut mucosal barrier. However, substantial research on specific effects, safety and action mechanisms in vivo should be done. In clinical application of humans and animals, there are still doubts about the precise evaluation of Lactobacilli's safety, therapeutic effect, dosage and other aspects. Therefore, we provide an overview of central issues on the impacts of Lactobacillus casei (L. casei) and their products on the intestinal mucosal barrier and some diseases and highlight the urgent need for further studies.

Limosilactobacillus reuteri DS0384 promotes intestinal epithelial maturation via the postbiotic effect in human intestinal organoids and infant mice

Little is known about the modulatory capacity of the microbiota in early intestinal development. We examined various intestinal models that respond to gut microbial metabolites based on human pluripotent stem cell-derived human intestinal organoids (hIOs): physiologically relevant in vitro fetal-like intestine, intestinal stem cell, and intestinal disease models. We found that a newly isolated Limosilactobacillus reuteri strain DS0384 accelerated maturation of the fetal intestine using 3D hIO with immature fetal characteristics. Comparative metabolomic profiling analysis revealed that the secreted metabolite N-carbamyl glutamic acid (NCG) is involved in the beneficial effect of DS0384 cell-free supernatants on the intestinal maturation of hIOs. Experiments in an intestinal stem cell spheroid model and hIO-based intestinal inflamed model revealed that the cell-free supernatant from DS0384 comprising NCG promoted intestinal stem cell proliferation and was important for intestinal protection against cytokine-induced intestinal epithelial injury. The probiotic properties of DS0384 were also evaluated, including acid and bile tolerance and ability to adhere to human intestinal cells. Seven-day oral administration of DS0384 and cell-free supernatant promoted the intestinal development of newborn mice. Moreover, NCG exerted a protective effect on experimental colitis in mice. These results suggest that DS0384 is a useful agent for probiotic applications and therapeutic treatment for disorders of early gut development and for preventing intestinal barrier dysfunction.

Efficacy and Safety of Lactobacillus reuteri CCFM1040 in Allergic Rhinitis and Asthma: A Randomized, Placebo-Controlled Trial

The coexistence of allergic rhinitis (AR) and asthma reinforces the concept of “one airway, one disease,” which has prompted the exploration for a single intervention to treat both diseases. Lactobacillus reuteri CCFM1040 (CCFM1040) was found to be an inhibitor of the common pathogenesis of AR and asthma in our previous studies. This study presented a randomized, placebo-controlled trial to investigate the clinical effects of CCFM1040 on both diseases. The total symptom score (TSS), the quality of life (QoL), and the modulation in the gut microbiota of patients with AR, the Asthma Control and Test (ACT) of patients with asthma, and the safety of both AR and asthma were measured. In patients with AR, CCFM1040 numerically decreased TSS, Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), 3 nasal scores in TSS (nasal congestion, watery eyes, and rhinorrhea), and sleep and significantly improved (P = 0.014) non-nose/eye symptoms. The ACT score was numerically increased in patients with asthma (from partially controlled to well-controlled). Significant microbial (from class level to genus level) and metabolic differences (P < 0.05) were found in patients with AR. No adverse reactions were observed. No effect on the blood and urine routine indexes. CCFM1040 has a potential benefit on both diseases. Further studies based on these findings will help to optimize the management of AR and asthma.

Innate and adaptive immunity in allergic airway disease

PURPOSE OF REVIEW

This article explores recent findings on the involvement of innate immunity in allergic airways disease, concentrating on allergic rhinitis.

RECENT FINDINGS

We speculate on the ways in which environmental influences act to initiate inflammation and on how these may have altered in recent decades. Improved understanding of the mechanisms involved may reveal future possibilities for therapy.

SUMMARY

The complex nature of immunity - both innate and acquired - in airways disease has implications for prevention and for therapy and requires further elucidation.

Abnormalities in Gut Microbiota and Metabolism in Patients With Chronic Spontaneous Urticaria

Background

Increasing evidence suggests that the gut microbiome plays a role in the pathogenesis of allergy and autoimmunity. The association between abnormalities in the gut microbiota and chronic spontaneous urticaria (CSU) remains largely undefined.

Methods

Fecal samples were obtained from 39 patients with CSU and 40 healthy controls (HCs). 16S ribosomal RNA (rRNA) gene sequencing (39 patients with CSU and 40 HCs) and untargeted metabolomics (12 patients with CSU and 12 HCs) were performed to analyze the compositional and metabolic alterations of the gut microbiome in CSU patients and HCs.

Results

The 16S rRNA gene sequencing results showed a significant difference in the β-diversity of the gut microbiota, presented as the Jaccard distance, between CSU patients and HCs. No significant differences were found in the α-diversity of the gut microbiota between patients and HCs. At the phylum level, the major bacteria in the gut microbiome of patients with CSU were Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria. At the genus level, Lactobacillus, Turicibacter, and Lachnobacterium were significantly increased and Phascolarctobacterium was decreased in patients with CSU. PICRUSt and correlation analysis indicated that Lactobacillus, Turicibacter, and Phascolarctobacterium were positively related to G protein-coupled receptors. Metabolomic analysis showed that α-mangostin and glycyrrhizic acid were upregulated and that 3-indolepropionic acid, xanthine, and isobutyric acid were downregulated in patients with CSU. Correlation analysis between the intestinal microbiota and metabolites suggested that there was a positive correlation between Lachnobacterium and α-mangostin.

Conclusions

This study suggests that disturbances in the gut microbiome composition and metabolites and their crosstalk or interaction may participate in the pathogenesis of CSU.

Prevalence of Detection of Clostridioides difficile Among Asymptomatic Children: A Systematic Review and Meta-analysis

IMPORTANCE

Detection of Clostridioides difficile has frequently been described in asymptomatic infants and children, but accurate estimates across the age spectrum are unavailable.

OBJECTIVE

To assess the prevalence of C difficile detection among asymptomatic children across the age spectrum.

DATA SOURCES

This systematic review and meta-analysis included a search of the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, Scopus, and Web of Science for articles published from January 1, 1990, to December 31, 2020. Search terms included Clostridium difficile, Peptoclostridium difficile, Clostridioides difficile, CDF OR CDI OR c diff OR c difficile, Clostridium infections OR cd positive diarrhea OR cd positive diarrhea OR Clostridium difficile OR Peptoclostridium difficile OR pseudomembranous colitis OR pseudomembranous enterocolitis, enterocolitis, and pseudomembranous. These were combined with the following terms: bacterial colonization and colonization OR colonized OR colonizing OR epidemiology OR prevalence OR seroprevalence.

STUDY SELECTION

Studies were screened independently by 2 authors. Studies were included if they reported testing for C difficile among asymptomatic children (ie, children without diarrhea) younger than 18 years.

DATA EXTRACTION AND SYNTHESIS

Data were extracted independently and in duplicate by 2 reviewers. Preferred Reporting Items for a Systematic Review and Meta-analysis (PRISMA) guidelines were used. Data were pooled using a random-effects model.

MAIN OUTCOMES AND MEASURES

The primary outcome was prevalence of C difficile detection among asymptomatic children. Secondary outcomes included prevalence of toxigenic vs nontoxigenic strains of C difficile and prevalence of C difficile detection stratified by geographic region, income status, testing method, and year of testing.

RESULTS

A total of 95 studies with 19 186 participants were included. Rates of detection of toxigenic or nontoxigenic C difficile were greatest among infants aged 6 to 12 months (41%; 95% CI, 32%-50%) and decreased to 12% (95% CI, 7%-18%) among children aged 5 to 18 years. The prevalence of toxigenic C difficile colonization was lower, peaking at 14% (95% CI, 8%-21%) among infants aged 6 to 12 months and decreasing to 6% (95% CI, 2%-11%) among children older than 5 years. Although prevalence differed by geographic region (ie, North and South America vs Europe: β, -0.151, P = .001; North and South America vs Western Pacific: β, 0.136, P = .007), there was no difference by testing method (ie, culture vs polymerase chain reaction: β, 0.069, P = .052; culture vs enzyme immunoassay: β, -0.178, P = .051), income class (low-middle income vs high income: β, -0.144, P = .23; upper-middle vs high income: β, -0.020, P = .64), or period (before 1990 vs 2010-2020: β, -0.125, P = .19; 1990-1999 vs 2010-2020: β, -0.037, P = .42; 2000-2009 vs 2010-2020: β, -0.006, P = .86).

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, C difficile colonization rates among children were greatest at 6 to 12 months of age and decreased thereafter. These estimates may provide context for interpreting C difficile test results among young children.

Natural immunomodulating substances used for alleviating food allergy

Food allergy is a serious health problem affecting more than 10% of the human population worldwide. Medical treatments for food allergy remain limited because immune therapy is risky and costly, and anti-allergic drugs have many harmful side effects and can cause drug dependence. In this paper, we review natural bioactive substances capable of alleviating food allergy. The sources of the anti-allergic substances reviewed include plants, animals, and microbes, and the types of substances include polysaccharides, oligosaccharides, polyphenols, phycocyanin, polyunsaturated fatty acids, flavonoids, terpenoids, quinones, alkaloids, phenylpropanoids, and probiotics. We describe five mechanisms involved in anti-allergic activities, including binding with epitopes located in allergens, affecting the gut microbiota, influencing intestinal epithelial cells, altering antigen presentation and T cell differentiation, and inhibiting the degranulation of effector cells. In the discussion, we present the limitations of existing researches as well as promising advances in the development of anti-allergic foods and/or immunomodulating food ingredients that can effectively prevent or alleviate food allergy. This review provides a reference for further research on anti-allergic materials and their hyposensitizing mechanisms.

Multidimensional study of the oral microbiome, metabolite, and immunologic environment in peanut allergy

BACKGROUND

The oral mucosa is the initial interface between food antigens, microbiota, and mucosal immunity, yet, little is known about oral host-environment dynamics in food allergy.

OBJECTIVE

Our aim was to determine oral microbial, metabolic, and immunologic profiles associated with peanut allergy.

METHODS

We recruited 105 subjects (56 with peanut allergy and 49 healthy subjects) for salivary microbiome profiling using 16S ribosomal RNA sequencing, short-chain fatty acid (SCFA) metabolite assays using liquid chromatography/mass spectrometry, and measurement of oral secreted cytokines using multiplex assays. Analyses within and across data types were performed.

RESULTS

The oral microbiome of individuals with peanut allergy was characterized by reduced species in the orders Lactobacillales, Bacteroidales (Prevotella spp), and Bacillales, and increased Neisseriales spp. The distinct oral microbiome of subjects with peanut allergy was accompanied by significant reductions in oral SCFA levels, including acetate, butyrate, and propionate, and significant elevation of IL-4 secretion. Decreased abundances of oral Prevotella spp and Veillonella spp in subjects with peanut allergy were significantly correlated with reduced oral SCFA levels (false discovery rate < 0.05), and increased oral Neisseria spp was correlated with lower oral SCFA levels (false discovery rate < 0.05). Additionally, oral Prevotella spp abundances were correlated with decreased local secretion of TH2-stimulating epithelial factors (IL-33 and thymic stromal lymphopoietin) and TH2 cytokines (IL-4, IL-5, and IL-13), whereas oral Neisseria spp abundance was positively associated with a TH2-skewed oral immune milieu.

CONCLUSION

Our novel multidimensional analysis of the oral environment revealed distinct microbial and metabolic profiles associated with mucosal immune disturbances in peanut allergy. Our findings highlight the oral environment as an anatomic site of interest to examine host-microbiome dynamics in food allergy.

Administration of All-Trans Retinoic Acid to Pregnant Sows Alters Gut Bacterial Community of Neonatal Piglets With Different Hoxa1 Genotypes

Administration of all-trans retinoic acid (ATRA) to pregnant sows improves developmental defects of Hoxa1-/- fetal pigs, and this study aimed to explore the influence of maternal ATRA administration during pregnancy on gut microbiota of neonatal piglets. Samples of jejunal and ileal meconium of neonatal piglets before suckling were collected including 5 Hoxa1-/- and 20 non-Hoxa1-/- (Hoxa1+/+ and Hoxa1+/-) neonatal piglets from the control group and 5 Hoxa1-/- and 7 non-Hoxa1-/- neonatal piglets from the experimental group. Results indicated that Hoxa1 mutation shaped the bacterial composition of the jejunum and ileum of neonatal piglets and Hoxa1-/- neonatal piglets had significantly higher diversity and species richness, higher relative abundance of phylum Bacteroidetes, lower relative abundances of phylum Firmicutes and genus Lactobacillus, and lower ratio of Firmicutes to Bacteroidetes than non-Hoxa1-/- neonatal piglets. After maternal ATRA administration, Hoxa1-/- neonatal piglets had significantly higher diversity and species richness, higher relative abundances of two bacterial phyla (Bacteroidetes and Proteobacteria), and lower relative abundances of phylum Firmicutes and genus Lactobacillus in the jejunum than non-Hoxa1-/- neonatal piglets. Hoxa1-/- neonatal piglets delivered by sows with maternal ATRA administration had lower diversity and species richness and higher relative abundance of phylum Firmicutes in the jejunum than Hoxa1-/- neonatal piglets born by sows with no maternal ATRA administration. Non-Hoxa1-/- neonatal piglets delivered by sows with maternal ATRA administration had higher diversity and species richness and significantly lower relative abundances of phyla Firmicutes and Actinobacteria and genus Lactobacillus in the ileum than non-Hoxa1-/- neonatal piglets born by sows with no maternal ATRA administration. Hoxa1 mutation decreased the expression of bacterial genes involved in ABC transporters, purine metabolism, and aminoacyl-tRNA biosynthesis and increased the expression of bacterial genes involved in two-component system, starch and sucrose metabolism, and arginine and proline metabolism. Maternal ATRA administration decreased the expression of bacterial genes involved in arginine and proline metabolism, peptidoglycan biosynthesis, and fatty acid biosynthesis. Hoxa1 mutation resulted in bacterial dysbiosis of the small intestine of Hoaxa1-/- neonatal piglets, and maternal ATRA administration restored the bacterial dysbiosis of Hoxa1-/- neonatal piglets and altered the bacterial composition of the small intestine of non-Hoxa1-/- neonatal piglets.

A good start in life is important-perinatal factors dictate early microbiota development and longer term maturation

Maternal health status is vital for the development of the offspring of humans, including physiological health and psychological functions. The complex and diverse microbial ecosystem residing within humans contributes critically to these intergenerational impacts. Perinatal factors, including maternal nutrition, antibiotic use and maternal stress, alter the maternal gut microbiota during pregnancy, which can be transmitted to the offspring. In addition, gestational age at birth and mode of delivery are indicated frequently to modulate the acquisition and development of gut microbiota in early life. The early-life gut microbiota engages in a range of host biological processes, particularly immunity, cognitive neurodevelopment and metabolism. The perturbed early-life gut microbiota increases the risk for disease in early and later life, highlighting the importance of understanding relationships of perinatal factors with early-life microbial composition and functions. In this review, we present an overview of the crucial perinatal factors and summarise updated knowledge of early-life microbiota, as well as how the perinatal factors shape gut microbiota in short and long terms. We further discuss the clinical consequences of perturbations of early-life gut microbiota and potential therapeutic interventions with probiotics/live biotherapeutics.

Association of early-life gut microbiome and lifestyle factors in the development of eczema in Hong Kong infants

Childhood eczema is common but its prevalence is variable in different regions of the world. In this study, we explore the associations of various risk factors such as the microbiome, environment, lifestyle, diet and maternal stress with the development of eczema among infants in Hong Kong. Upon enrolment in the study, the infants' parents provided demographic data by self-reporting. At enrolment and 1 year after birth, the infants' allergic conditions, lifestyles and dietary factors and the degree of maternal stress were assessed using various questionnaires. The infants' gut microbiomes were analysed by 16S RNA sequencing, and the longitudinal changes in various bacterial strains were compared between control and eczema-affected groups. Multivariate analyses (after adjustment for other significant factors) revealed that the changes in the abundance of Hungatella hathewayi in the gut were significantly associated with the development of eczema (p = 0.005). In conclusion, the increased abundance of Hungatella hathewayi was associated with an increased risk of developing eczema by 1 year of age. This study thus explored the potential risk factors for the development of eczema in Hong Kong infants, and sheds light on the possible association between early-life gut microbiome and other environmental factors.

The Role of Short-Chain Fatty Acids in the Interplay between a Very Low-Calorie Ketogenic Diet and the Infant Gut Microbiota and Its Therapeutic Implications for Reducing Asthma

Gut microbiota is well known as playing a critical role in inflammation and asthma development. The very low-calorie ketogenic diet (VLCKD) is suggested to affect gut microbiota; however, the effects of VLCKD during pregnancy and lactation on the infant gut microbiota are unclear. The VLCKD appears to be more effective than caloric/energy restriction diets for the treatment of several diseases, such as obesity and diabetes. However, whether adherence to VLCKD affects the infant gut microbiota and the protective effects thereof on asthma remains uncertain. The exact mechanisms underlying this process, and in particular the potential role of short chain fatty acids (SCFAs), are still to be unravelled. Thus, the aim of this review is to identify the potential role of SCFAs that underlie the effects of VLCKD during pregnancy and lactation on the infant gut microbiota, and explore whether it incurs significant implications for reducing asthma.

Mechanisms Underlying the Skin-Gut Cross Talk in the Development of IgE-Mediated Food Allergy

Immune-globulin E (IgE)-mediated food allergy is characterized by a variety of clinical entities within the gastrointestinal tract, skin and lungs, and systemically as anaphylaxis. The default response to food antigens, which is antigen specific immune tolerance, requires exposure to the antigen and is already initiated during pregnancy. After birth, tolerance is mostly acquired in the gut after oral ingestion of dietary proteins, whilst exposure to these same proteins via the skin, especially when it is inflamed and has a disrupted barrier, can lead to allergic sensitization. The crosstalk between the skin and the gut, which is involved in the induction of food allergy, is still incompletely understood. In this review, we will focus on mechanisms underlying allergic sensitization (to food antigens) via the skin, leading to gastrointestinal inflammation, and the development of IgE-mediated food allergy. Better understanding of these processes will eventually help to develop new preventive and therapeutic strategies in children.

The student-centered classroom: the new gut feeling

A student-centered, interactive course-based undergraduate research experience (CURE) was implemented in a microbiology course in order to provide an authentic research experience and to stimulate student interest and improve understanding of fermentation, probiotics, the human microbiome and related topics. Students were immersed in the scientific process as they used fundamental techniques to investigate the probiotic composition of a fermented milk beverage, kefir-an unknown question with no predetermined outcomes. In order to assess the benefits and effect of this learning experience on the students, pre- and post-study surveys were administered using Qualtrics. Post-study, 93% of participants agreed that fermented foods are beneficial to human health (compared to 52% pre-study), and notably, 100% of participants indicated that they plan to apply this material in both their personal and professional lives and would suggest consuming probiotics or fermented products to alleviate gastrointestinal issues. As evidenced by demographic data, this CURE is suitable for implementation at both large and small institutions with diverse student populations. Collectively, these data indicate that this collaborative, discovery-based learning experience is a powerful educational tool, encouraging students to make real-life connections between microbiology, medicine and their own health.

Fermentation revival in the classroom: investigating ancient human practices as CUREs for modern diseases

A course-based undergraduate research experience (CURE) was designed to integrate key microbiological principles and techniques into an authentic research experience in a classroom setting and was implemented in an undergraduate microbiology laboratory course. Students conducted a 6-week study in order to determine the identity and quantity of unique probiotic species from various types of kefir. This course module followed an inquiry-based pedagogical approach in which students use the scientific process to investigate an unknown question with no predetermined outcome. During each lab, relevant microbiological topics and laboratory concepts were presented. Students then performed various laboratory techniques, reinforcing the lecture material with hands-on experience. In addition, students participated in reflection through group presentation of their results, bioinformatic analysis and literature review. Based on data collected from pre- and post-study survey responses, both student knowledge and attitudes towards the topics covered improved due to participation in this CURE. Importantly, this CURE can be implemented at many levels of education, requiring only minimal resources and common laboratory equipment.

Interaction between Maternal Immune Activation and Antibiotic Use during Pregnancy and Child Risk of Autism Spectrum Disorder

Prenatal exposure to maternal immune activation (MIA) has been implicated as a risk factor for the development of autism spectrum disorder (ASD), though the conditions under which this elevated risk occurs are unclear. Animal literature demonstrates that antibiotic use, which affects the composition of the maternal gut microbiota, modifies the effect of MIA on neurodevelopmental outcomes in the offspring. The aim of this study was to assess whether antibiotic use during pregnancy modifies the association between MIA and subsequent risk of ASD, in a prospective birth cohort with 116 ASD cases and 860 typically developing (TD) child controls. There was no evidence of interaction between fever or genitourinary infection and antibiotic use on the odds of ASD in unadjusted or adjusted analyzes. However, we found evidence of an interaction between flu, specifically in second trimester, and antibiotic use at any point during pregnancy on the odds of ASD in the child. Among women who received an antibiotic during pregnancy, flu in trimester two was not associated with ASD (adjusted odds ratio [aOR] = 0.99 [0.43-2.28]). Among women who were not exposed to an antibiotic at any point during pregnancy, flu in second trimester was significantly associated with increased odds of ASD (aOR = 4.05 [1.14-14.38], P = .03), after adjustment for child sex, child birth year, maternal age, gestational age, C-section delivery, and low birthweight. These findings should be treated as hypothesis-generating and suggest that antibiotic use may modify the influence that MIA has on autism risk in the child. LAY SUMMARY: We looked at whether the association between activation of the immune system during pregnancy and risk of the child developing autism spectrum disorder (ASD) differed among women who did or did not take an antibiotic at any point during pregnancy. We examined 116 children with ASD and 860 without ASD and found that flu in second trimester was associated with increased ASD, but only among women who did not take an antibiotic during pregnancy. No other immune activation exposures seemed to interact with antibiotic use.

Childhood allergy is preceded by an absence of gut lactobacilli species and higher levels of atopy-related plasma chemokines

Alterations in the composition and reduced diversity of the infant microbiome are associated with allergic disease in children. Further, an altered microbiota is linked to immune dysregulation, including skewing of different T helper (Th) subsets, which is also seen in atopic individuals. The aim of this study was, therefore, to investigate the associations between gut lactobacilli and Th‐related plasma factors in allergy development during childhood. A total of 194 children with known allergy status at 1 year of age were followed to 10 years of age. We used real‐time polymerase chain reaction (PCR) to investigate the presence of three lactobacilli species (Lactobacillus casei, L. paracasei, L. rhamnosus) in infant fecal samples (collected between 1 week and 2 months of age) from a subgroup of children. Plasma chemokines and cytokines were quantified at 6 months and at 1, 2, 5 and 10 years of age with Luminex or enzyme‐linked immunosorbent assay (ELISA). Fractional exhaled nitrogen oxide (FeNO) was measured and spirometry performed at 10 years of age. The data were analysed by non‐parametric testing and a logistic regression model adjusted for parental allergy. An absence of these lactobacilli and higher levels of the chemokines BCA‐1/CXCL13, CCL17/TARC, MIP‐3α/CCL20 and MDC/CCL22 in plasma at 6 months of age preceded allergy development. The presence of lactobacilli associated with lower levels of atopy‐related chemokines during infancy, together with higher levels of interferon (IFN)‐γ and lower FeNO during later childhood. The results indicate that the presence of certain lactobacilli species in the infant gut may influence allergy‐related parameters in the peripheral immune system, and thereby contribute to allergy protection.

A dietary intervention to improve the microbiome composition of pregnant women with Crohn's disease and their offspring: The MELODY (Modulating Early Life Microbiome through Dietary Intervention in Pregnancy) trial design

Crohn's disease (CD), a type of inflammatory bowel disease (IBD), is a chronic condition of the gastrointestinal tract that is caused by the loss of mucosal tolerance towards the commensal bacteria resulting in inflammatory responses. It has long been postulated that the gut microbiota, a complex and dynamic population of microorganisms, plays a key role in the pathogenesis of IBD. Maternal diagnosis of IBD has been identified as the greatest risk factor for IBD in offspring increasing the odds of developing the disease >4.5-fold. Moreover, babies born to mothers with IBD have demonstrated reduced gut bacterial diversity. There is accumulating evidence that the early life microbiota colonization is informed by maternal diet within the 3rd trimester of pregnancy. While babies born to mothers with IBD would pose an ideal cohort for intervention, no primary prevention measures are currently available. Therefore, we designed the MELODY (Modulating Early Life Microbiome through Dietary Intervention in Pregnancy) trial to test whether the IBD-AID™ dietary intervention during the last trimester of pregnancy can beneficially shift the microbiome of CD patients and their babies, thereby promoting a strong, effective immune system during a critical time of the immune system development. We will also test if favorable changes in the microbiome can lead to a reduced risk of postpartum CD relapse and lower mucosal inflammation in the offspring. This study will help create new opportunities to foster a healthy microbiome in the offspring at high risk of other immune-mediated diseases, potentially reducing their risk later in life.

Lactobacillus reuteri attenuated allergic inflammation induced by HDM in the mouse and modulated gut microbes

Gut microbiome plays an essential role in asthma development, and probiotic-based manipulation of the gut microbiome has been proposed to prevent asthma. Although the preventive effect of Lactobacillus supplementation against allergies has been reported, the precise Lactobacillus species beneficial for effective prevention of asthma remain unidentified and the underlying mechanisms remain unclear. Therefore, we aimed to investigate the efficacy of oral administration of six Lactobacillus species and the mechanism underlying asthma prevention via gut microbiome modulation. We investigated the effects of oral administration of L. rhamnosus, L. fermentum, L. casei, L. gasseri, L. salivarius, and L. reuteri (five strains of each species) on asthma and gut microbiome of house dust mite (HDM)-treated murine models of asthma. Of these, L. reuteri administration was the most effective: it alleviated airway inflammation, decreased total IgE and HDM-IgG1, and reduced Th2-associated pro-inflammatory cytokines. Moreover, modulation of specific microbial genera by L. reuteri was more effective in asthma prevention than the modulation of the overall microbiota composition. Lactobacillus and Enterococcus were enriched after L. reuteri supplementation and were closely associated with total IgE and IL-13 production. Furthermore, L. reuteri specifically altered the gut microbial function toward butyrate generation. Thus, L. reuteri may reduce the risk of asthma development by modulating specific gut microbiota to improve the lung immune environment. Our study suggests a novel option for gut microbiome manipulation via L. reuteri supplementation for suppression of asthma and other allergic diseases.

Response of the Human Milk Microbiota to A Maternal Prebiotic Intervention is Individual and Influenced by Maternal Age

Maternal bacteria are shared with infants via breastfeeding. Prebiotics modulate the gut microbiota, promoting health benefits. We investigated whether the maternal diet supplementation with a prebiotic (fructooligosaccharides, FOS) could influence the milk microbiota. Twenty-eight lactating women received 4.5 g of fructooligosaccharides + 2 g of maltodextrin (FOS group) and twenty-five received 2 g of maltodextrin (placebo group) for 20 days. Breast-milk samples were taken before and after the intervention. The DNA from samples was used for 16S rRNA sequencing. No statistical differences between the groups were found for the bacterial genera after the intervention. However, the distances of the trajectories covered by paired samples from the beginning to the end of the supplementation were higher for the FOS group (p = 0.0007) indicating greater changes in milk microbiota compared to the control group. Linear regression models suggested that the maternal age influenced the response for FOS supplementation (p = 0.02). Interestingly, the pattern of changes to genus abundance upon supplementation was not shared between mothers. We demonstrated that manipulating the human milk microbiota through prebiotics is possible, and the maternal age can affect this response.&nbsp.

Gut microbiota of children with atopic dermatitis: Controlled study in the metropolitan region of São Paulo, Brazil

BACKGROUND

It is possible that imbalances in the composition of the gut microbiota or the relationship of the microbiota with the host may be implicated in the origin of allergy. Therefore, we studied the intestinal microbiota of children with atopic dermatitis (AD).

METHODS

Cross-sectional study with 81 children aged 5-11; 23 with AD and 58 controls. Surveys were conducted to obtain demographic, socioeconomic and neonatal data. Diagnosis of AD was made based on the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Eubacteria, Bacteroidetes, Firmicutes, B. fragilis, E. coli, Lactobacillus spp., S. aureus, E. faecalis, Salmonella spp., M. smithii, Bifidobacterium spp., C. difficile and C. perfringens were quantified using real-time PCR.

RESULTS

The analysis showed an association between presence of C. difficile (OR: 5.88; 95 % CI: 1.24; 27.98), greater abundance of bifidobacteria (OR: 11.09; 95 % CI: 2.14; 57.39) and a lower abundance of lactobacilli (OR: 0.07; 95 % CI: 0.01; 0.51) in the gut microbiota of children with AD. Counts of Eubacteria (0,05×10³ and 8.49×10³), B. fragilis (0.72×10⁹ and 4.5×10⁹), Lactobacillus spp. (0.02×10⁸ and 0.38×10⁸), E. coli (0.13×10⁹ and 1.52×10⁹) and M. smithii (0.02×10⁸ and 0.31×10⁸) were lower in children with AD (P<0.05).

CONCLUSIONS

This study confirmed that children living in the metropolitan area of São Paulo (Brazil) with AD have a different microbiota pattern with higher prevalence of C. difficile, lower abundance of Lactobacillus and greater abundance of bifidobacteria, regardless of socioeconomic status.

Gut Microbiome and Serum Metabolome Analyses Identify Unsaturated Fatty Acids and Butanoate Metabolism Induced by Gut Microbiota in Patients With Chronic Spontaneous Urticaria

Chronic urticaria (CU) is defined as the continuous or intermittent presence of urticaria for a period exceeding 6 weeks and sometimes occurring with angioedema. Between 66 and 93% of patients with CU have chronic spontaneous urticaria (CSU), the precise pathogenesis of which is largely unknown. The aim of this study was to determine the relationship between gut microbiota and serum metabolites and the possible pathogenesis underlying CSU. We collected feces and blood samples from CSU patients and healthy controls and the relationship between gut microbiota and serum metabolites was assessed using 16S rRNA gene sequencing and untargeted metabolomic analyses. The CSU group exhibited decreased alpha diversity of the microbial population compared to the control group. The abundance of unidentified Enterobacteriaceae was increased, while the abundance of Bacteroides, Faecalibacterium, Bifidobacterium, and unidentified Ruminococcaceae was significantly reduced in CSU patients. The serum metabolome analysis revealed altered levels of docosahexaenoic acid, arachidonic acid, glutamate, and succinic acid, suggesting changes in unsaturated fatty acids and the butanoate metabolism pathway. The combined serum metabolomics and gut microbiome datasets were correlated; specifically, docosahexaenoic acid, and arachidonic acid were positively correlated with Bacteroides. We speculate that alterations in gut microbes and metabolites may contribute to exacerbated inflammatory responses and dysregulated immune function with or without regulatory T cell dependence in the pathogenesis of CSU.

High levels of fucosylation and sialylation of milk N-glycans from mothers with gestational diabetes mellitus alter the offspring gut microbiome and immune balance in mice

Gestational diabetes mellitus (GDM) is significantly associated with allergen sensitization in early childhood, and this may influence the gut microbiome and immune system of the children. In addition to mother-to-child transmission of microbes, milk glycans play a pivotal role in shaping the gut microbiome of infants. A previous study has demonstrated alterations in the major milk N-glycans of mothers with GDM. However, the impact of these changes on the gut microbiome and immune response of the neonates has yet to be studied. Here, we aimed to compare the glycosylation levels of various milk glycans between normal and GDM mice, and to characterize the intestinal microbiome and immune responses of the offspring after weaning. We found that GDM mouse milk contained significantly higher concentrations of fucosylated and sialylated N-glycans than control mice, but there was no difference in the concentration of milk oligosaccharides between the groups. The differences in milk N-glycans had direct effects on the intestinal microbiome of the offspring, which in turn affected their immune response upon challenge with ovalbumin (OVA), with disruptions in the Th1/Th2 and Th17/Treg cell balances. This study lays the foundation for further research and development of specific nutritional care for the offspring of GDM mothers.

Extracellular Membrane Vesicles from Lactobacilli Dampen IFN-γ Responses in a Monocyte-Dependent Manner

Secreted factors derived from Lactobacillus are able to dampen pro-inflammatory cytokine responses. Still, the nature of these components and the underlying mechanisms remain elusive. Here, we aimed to identify the components and the mechanism involved in the Lactobacillus-mediated modulation of immune cell activation. PBMC were stimulated in the presence of the cell free supernatants (CFS) of cultured Lactobacillus rhamnosus GG and Lactobacillus reuteri DSM 17938, followed by evaluation of cytokine responses. We show that lactobacilli-CFS effectively dampen induced IFN-γ and IL-17A responses from T- and NK cells in a monocyte dependent manner by a soluble factor. A proteomic array analysis highlighted Lactobacillus-induced IL-1 receptor antagonist (ra) as a potential candidate responsible for the IFN-γ dampening activity. Indeed, addition of recombinant IL-1ra to stimulated PBMC resulted in reduced IFN-γ production. Further characterization of the lactobacilli-CFS revealed the presence of extracellular membrane vesicles with a similar immune regulatory activity to that observed with the lactobacilli-CFS. In conclusion, we have shown that lactobacilli produce extracellular MVs, which are able to dampen pro-inflammatory cytokine responses in a monocyte-dependent manner.

Household composition and the infant fecal microbiome: The INSPIRE study

OBJECTIVES

Establishment and development of the infant gastrointestinal microbiome (GIM) varies cross-culturally and is thought to be influenced by factors such as gestational age, birth mode, diet, and antibiotic exposure. However, there is little data as to how the composition of infants' households may play a role, particularly from a cross-cultural perspective. Here, we examined relationships between infant fecal microbiome (IFM) diversity/composition and infants' household size, number of siblings, and number of other household members.

MATERIALS AND METHODS

We analyzed 377 fecal samples from healthy, breastfeeding infants across 11 sites in eight different countries (Ethiopia, The Gambia, Ghana, Kenya, Peru, Spain, Sweden, and the United States). Fecal microbial community structure was determined by amplifying, sequencing, and classifying (to the genus level) the V1-V3 region of the bacterial 16S rRNA gene. Surveys administered to infants' mothers identified household members and composition.

RESULTS

Our results indicated that household composition (represented by the number of cohabitating siblings and other household members) did not have a measurable impact on the bacterial diversity, evenness, or richness of the IFM. However, we observed that variation in household composition categories did correspond to differential relative abundances of specific taxa, namely: Lactobacillus, Clostridium, Enterobacter, and Klebsiella.

DISCUSSION

This study, to our knowledge, is the largest cross-cultural study to date examining the association between household composition and the IFM. Our results indicate that the social environment of infants (represented here by the proxy of household composition) may influence the bacterial composition of the infant GIM, although the mechanism is unknown. A higher number and diversity of cohabitants and potential caregivers may facilitate social transmission of beneficial bacteria to the infant gastrointestinal tract, by way of shared environment or through direct physical and social contact between the maternal-infant dyad and other household members. These findings contribute to the discussion concerning ways by which infants are influenced by their social environments and add further dimensionality to the ongoing exploration of social transmission of gut microbiota and the "old friends" hypothesis.

Michigan cohorts to determine associations of maternal pre-pregnancy body mass index with pregnancy and infant gastrointestinal microbial communities: Late pregnancy and early infancy

BACKGROUND

About 25% of women in the United States are obese prior to becoming pregnant. Although there is some knowledge about the relationship between the gastrointestinal microbiota and obesity, little is known about the relationship between pre-pregnancy obesity and the gastrointestinal microbiota in pregnancy or its impact on infant gut microbiota. However, the composition of the gut microbiota early in life may influence childhood health. Thus, the objective of this research was to identify associations between maternal pre-pregnancy obesity and the pregnancy (n = 39) or early infancy (n = 39) microbiotas.

RESULTS

Fecal bacterial communities from overweight women had lower microbiota diversity (Chao1: p = 0.02; inverse Simpson: p = 0.05; Shannon: p = 0.02) than communities from normal weight or obese women. The within-group microbiota composition of overweight women differed from those of normal and obese women at the genus and phylum levels (p = 0.003 and p = 0.02, respectively). Pre-pregnancy overweight women had higher abundances of Bacteroides and lower Phascolarctobacterium than women who were normal weight or obese prior to becoming pregnant. Normal weight women had lower abundances of Acidaminococcus and Dialister than overweight and obese women. Infant community composition tended to differ in membership (Sorensen index) by maternal pre-pregnancy BMI category, and significantly differed by delivery mode and breastfeeding exclusivity (p = 0.06, p = 0.001, p = 0.008, respectively). Infants from normal weight women had lower abundances of Megasphaera than infants from overweight or obese women. Streptococcus was lowest in infants from overweight women, and Staphylococcus was lowest in infants from obese women.

CONCLUSION

Maternal and infant microbiotas are associated with and might be affected by maternal pre-pregnancy BMI. Future work should determine if there are also functional differences in the infant microbiome, if those functional differences are related to maternal pre-pregnancy BMI, and whether differences in composition or traits persist over time.

Birth Mode, Breastfeeding, Pet Exposure, and Antibiotic Use: Associations With the Gut Microbiome and Sensitization in Children

PURPOSE OF REVIEW

The infant gut microbiota has become a focus of multiple epidemiologic and cohort studies. This microbiome is derived from the mother (via the vaginal canal, maternal skin contact, breastfeeding, and possibly in utero microbial transfer) and is likely influenced by multiple external factors. It is now believed by some experts that colonization and formation of the newborn and alterations of gut microbiota in children are dependent on earlier alterations of the microbiota of mothers during or perhaps even before pregnancy. This review will focus on specific factors (pet keeping, breastfeeding, antibiotic use, and mode of delivery) that influence the infant gut microbiome and atopy.

RECENT FINDINGS

This is a review of recent literature describing how pet keeping, breastfeeding, antibiotic use, and mode of delivery influences and changes the infant gut microbiome and atopy. General trends in gut microbiota differences have emerged in different birth cohorts when each external factor is analyzed, but consistency between studies is difficult to replicate. The aforementioned factors do not seem to confer an overwhelming risk for development of atopy alone. This review provides a comprehensive review of early life environmental factors and their influence on the infant gut microbiome and atopy.

Shaping the Gut Microbiota by Breastfeeding: The Gateway to Allergy Prevention?

Evidence is accumulating that demonstrates the importance of the gut microbiota in health and diseases such as allergy. Recent studies emphasize the importance of the "window of opportunity" in early life, during which interventions altering the gut microbiota induce long-term effects. The neonate's gut microbiota composition and metabolism could therefore play an essential role in allergic disease risk. Breastfeeding shapes the gut microbiota in early life, both directly by exposure of the neonate to the milk microbiota and indirectly, via maternal milk factors that affect bacterial growth and metabolism such as human milk oligosaccharides, secretory IgA, and anti-microbial factors. The potential of breastmilk to modulate the offspring's early gut microbiota is a promising tool for allergy prevention. Here, we will review the existing evidence demonstrating the impact of breastfeeding on shaping the neonate's gut microbiota and highlight the potential of this strategy for allergy prevention.

Association between the intestinal microbiota and allergic sensitization, eczema, and asthma: A systematic review

The intestinal microbiota plays an important role in development of the immune system and regulation of immune responses. This review summarizes the association between the intestinal microbiota and the development of allergic sensitization, eczema, and asthma in neonates and children. Overall, a greater relative abundance of Bacteroidaceae, Clostridiaceae, and Enterobacteriaceae and a lower relative abundance of Bifidobacteriaceae and Lactobacillaceae is associated with the development of allergic sensitization, eczema, or asthma. Reduced bacterial diversity can be associated with the development of allergic disease. The association between the composition of the intestinal microbiota and the development of allergic disease or asthma is less consistent in older children than in neonates, suggesting that early-life microbial exposure plays a more important role. Inconsistencies in the results reported from different studies might partly be explained by heterogeneity in design, study populations, diagnostic criteria, microbiota analysis methods, and reporting on different taxonomic levels. Larger studies that better account for antenatal and postnatal factors will further help determine specific microbial intestinal signatures associated with increased risk of allergy and asthma. This will enable the early identification of infants at high risk and facilitate novel strategies and interventions to prevent and treat these conditions, including modifying the intestinal microbiota early in life.

Factors Influencing the Intestinal Microbiome During the First Year of Life

The intestinal microbiome plays a crucial role in the development of the immune system and regulation of immune responses. Many factors influence the composition of the infant intestinal microbiome and therefore the development and function of the immune system. This, in turn, may alter the risk of subsequent allergies, autoimmune diseases and other adverse health outcomes. Here, we review factors that influence the composition of the intestinal microbiome during the first year of life, including birth location, gestational age, delivery mode, feeding method, hospitalization, antibiotic or probiotic intake and living conditions. Understanding how the early intestinal microbiome is established and how this is perturbed provides many opportunities for interventions to improve health.

The Lactobacillus casei Group: History and Health Related Applications

The Lactobacillus casei group (LCG), composed of the closely related Lactobacillus casei, Lactobacillus paracasei, and Lactobacillus rhamnosus are some of the most widely researched and applied probiotic species of lactobacilli. The three species have been extensively studied, classified and reclassified due to their health promoting properties. Differentiation is often difficult by conventional phenotypic and genotypic methods and therefore new methods are being continually developed to distinguish the three closely related species. The group remain of interest as probiotics, and their use is widespread in industry. Much research has focused in recent years on their application for health promotion in treatment or prevention of a number of diseases and disorders. The LCG have the potential to be used prophylactically or therapeutically in diseases associated with a disturbance to the gut microbiota. The group have been extensively researched with regard to stress responses, which are crucial for their survival and therefore application as probiotics.

Epigenetics and Malaria Susceptibility/Protection: A Missing Piece of the Puzzle

A better understanding of stable changes in regulation of gene expression that result from epigenetic events is of great relevance in the development of strategies to prevent and treat infectious diseases. Histone modification and DNA methylation are key epigenetic mechanisms that can be regarded as marks, which ensure an accurate transmission of the chromatin states and gene expression profiles over generations of cells. There is an increasing list of these modifications, and the complexity of their action is just beginning to be understood. It is clear that the epigenetic landscape plays a fundamental role in most biological processes that involve the manipulation and expression of DNA. Although the molecular mechanism of gene regulation is relatively well understood, the hierarchical order of events and dependencies that lead to protection against infection remain largely unknown. In this review, we propose that host epigenetics is an essential, though relatively under studied, factor in the protection or susceptibility to malaria.

The protective effect of Lactobacillus and Bifidobacterium as the gut microbiota members against chronic urticaria

BACKGROUND

Chronic Urticaria is a common disorder which is defined by recurrent occurrence of wheals and sometimes angioedema. It has a notable influence on the patients' quality of life. Regulation of the immune system is one of the important roles of the gut microbiota. The effect of dysbiosis considering some members of gut microbiota in patients with chronic urticaria has been demonstrated in our previous study.

OBJECTIVE

Comparing the frequency and bacterial load of Lactobacillus, Bifidobacterium, and Bacteroides between patients with chronic urticaria and healthy controls.

METHODS

20 patients with chronic urticaria and 20 age and sex matched healthy individuals were included in the present study. Stool samples were analyzed for determining the frequency and bacterial load of Lactobacillus, Bifidobacterium, and Bacteroides genera.

RESULTS

There were no significant differences among the frequencies of detectable Lactobacillus, Bifidobacterium, or Bacteroides in stool samples of patients with chronic urticaria and healthy controls. The relative amounts of Lactobacillus and Bifidobacterium were significantly higher in fecal samples from controls compared to patients with chronic urticaria (P = 0.038 and 0.039, respectively).

CONCLUSION

It is the first study on the implication of Lactobacillus, Bifidobacterium, and Bacteroides genera as gut microbiota members in patients with chronic urticaria.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Immunological Effects of Human Milk Oligosaccharides

Human milk oligosaccharides (HMOs) comprise a group of structurally complex, unconjugated glycans that are highly abundant in human milk. HMOs are minimally digested in the gastrointestinal tract and reach the colon intact, where they shape the microbiota. A small fraction of HMOs is absorbed, reaches the systemic circulation, and is excreted in urine. HMOs can bind to cell surface receptors expressed on epithelial cells and cells of the immune system and thus modulate neonatal immunity in the infant gut, and possibly also sites throughout the body. In addition, they have been shown to act as soluble decoy receptors to block the attachment of various microbial pathogens to cells. This review summarizes the current knowledge of the effects HMOs can have on infections, allergies, auto-immune diseases and inflammation, and will focus on the role of HMOs in altering immune responses through binding to immune-related receptors.

Clinical Relevance of Gastrointestinal Microbiota During Pregnancy: A Primer for Nurses

Emerging evidence about the human microbiome, a collective term for all the microorganisms living in and on the human body, consistently demonstrates the critical influence it has on host physiology and disease risk. The microbiota in the gastrointestinal (GI) tract has the most significant and far-reaching effect on human physiology. The maternal GI microbiota can decrease the risk of adverse pregnancy outcomes by modulating energy extraction, glucose metabolism, vitamin production, and host immunity essential for optimal maternal and neonatal health. Moreover, the maternal GI microbiota is thought to influence colonization of the fetus and neonate that may predispose them to different health trajectories. This article provides a basic understanding about the influence of the structure of the maternal GI microbiota, the fundamental role it plays during pregnancy, and the factors that influence the structure, and subsequently function, of the GI microbiota in the general and pregnant population. While only a small number of studies have examined this topic during pregnancy, the preponderance of the evidence supports the need to clarify baseline structure and function of GI microbiota and its associations with pregnancy outcomes. In addition, the results from the studies conducted in the general population can be extrapolated to pregnancy in many cases. This knowledge is essential for clinicians who need to understand the implications of the microbiota for disease and wellness in order to address the care factors that may adversely influence the GI microbiota during pregnancy.

Intestinal Dysbiosis Featuring Abundance of Ruminococcus gnavus Associates With Allergic Diseases in Infants

BACKGROUND & AIMS

Dysbiosis of the intestinal microbiota has been associated with development of allergies in infants. However, it is not clear what microbes might contribute to this process. We investigated what microbe(s) might be involved in analyses of infant twins and mice.

METHODS

We studied fecal specimens prospectively in a twin cohort (n = 30) and age-matched singletons (n = 14) born at National Taiwan University Children's Hospital, Taipei, Taiwan, from April 2011 to March 2013. Clinical parameters (gestational age, birth body weight, mode of delivery and feeding, immunizations, and medical events) were recorded. Fecal samples were collected beginning immediately after birth and for 1 year; the children were followed until 3 years of age and allergic symptoms (repetitive and continuous for at least 6 months) were noted. A skin prick test was used to ascertain atopy. Bacterial communities in fecal samples were profiled by 16S ribosomal RNA-based polymerase chain reaction-temporal temperature gradient gel electrophoresis and next-generation sequencing. BALB/c mice without and with ovalbumin sensitization/challenge were infected with candidate bacteria by oral gauge intragastric intubation. Fecal, serum, lung, and colon tissue samples were collected from mice and analyzed for mechanisms of allergy development.

RESULTS

During the investigation period, 20 children (45.5%) developed allergic diseases, including respiratory (allergic rhinitis and asthma) and skin (atopic dermatitis and eczema) allergies. Lachnospiraceae were detected at significantly higher frequency in allergic infants than nonallergic infants (P < .004); the high fecal count of Lachnospiraceae in allergic subjects appeared at 2 months of age and persisted until 12 months of age. The enrichment of Lachnospiraceae in allergic infants was attributed to the overgrowth of Ruminococcus gnavus, which tended to have a low frequency in nonallergic subjects (P = .0004). Increased R gnavus was observed before the onset of allergic manifestations, and was associated with respiratory allergies (P < .002) or respiratory allergies coexistent with atopic eczema (P < .001). In mice, endogenous R gnavus grew rapidly after sensitization and challenge with ovalbumin. Mice gavaged with purified R gnavus developed airway hyper-responsiveness and had histologic evidence of airway inflammation (asthma). Expansion of R gnavus in mice stimulated secretion of cytokines (interleukin [IL] 25, IL33, and thymic stromal lymphopoietin) by colon tissues, which activated type 2 innate lymphoid cells and dendritic cells to promote differentiation of T-helper 2 cells and production of their cytokines (IL4, IL5, and IL13). This led to infiltration of the colon and lung parenchyma by eosinophils and mast cells.

CONCLUSIONS

In a study of a twin cohort (some infants with, some without allergies), we associated development of allergies, particularly respiratory allergies, with increased fecal abundance of R gnavus. Mice fed R gnavus developed airway inflammation, characterized by expansion of T-helper 2 cells in the colon and lung, and infiltration of colon and lung parenchyma by eosinophils and mast cells.

Adjuvant Probiotics and the Intestinal Microbiome: Enhancing Vaccines and Immunotherapy Outcomes

Immune defence against pathogenic agents comprises the basic premise for the administration of vaccines. Vaccinations have hence prevented millions of infectious illnesses, hospitalizations and mortality. Acquired immunity comprises antibody and cell mediated responses and is characterized by its specificity and memory. Along a similar congruent yet diverse mode of disease prevention, the human host has negotiated from in utero and at birth with the intestinal commensal bacterial cohort to maintain local homeostasis in order to achieve immunological tolerance in the new born. The advent of the Human Microbiome Project has redefined an appreciation of the interactions between the host and bacteria in the intestines from one of a collection of toxic waste to one of a symbiotic existence. Probiotics comprise bacterial genera thought to provide a health benefit to the host. The intestinal microbiota has profound effects on local and extra-intestinal end organ physiology. As such, we further posit that the adjuvant administration of dedicated probiotic formulations can encourage the intestinal commensal cohort to beneficially participate in the intestinal microbiome-intestinal epithelia-innate-cell mediated immunity axes and cell mediated cellular immunity with vaccines aimed at preventing infectious diseases whilst conserving immunological tolerance. The strength of evidence for the positive effect of probiotic administration on acquired immune responses has come from various studies with viral and bacterial vaccines. We posit that the introduction early of probiotics may provide significant beneficial immune outcomes in neonates prior to commencing a vaccination schedule or in elderly adults prior to the administration of vaccinations against influenza viruses.

Early-Life Human Microbiota Associated With Childhood Allergy Promotes the T Helper 17 Axis in Mice

The intestinal microbiota influences immune maturation during childhood, and is implicated in early-life allergy development. However, to directly study intestinal microbes and gut immune responses in infants is difficult. To investigate how different types of early-life gut microbiota affect immune development, we collected fecal samples from children with different allergic heredity (AH) and inoculated germ-free mice. Immune responses and microbiota composition were evaluated in the offspring of these mice. Microbial composition in the small intestine, the cecum and the colon were determined by 16S rRNA sequencing. The intestinal microbiota differed markedly between the groups of mice, but only exposure to microbiota associated with AH and known future allergy in children resulted in a T helper 17 (Th17)-signature, both systemically and in the gut mucosa in the mouse offspring. These Th17 responses could be signs of a particular microbiota and a shift in immune development, ultimately resulting in an increased risk of allergy.

Gut microbiota in early life and its influence on health and disease: A position paper by the Malaysian Working Group on Gastrointestinal Health

The role of gut microbiota in early life and its impact on gut health and subsequent diseases remain unclear. There is a lack of research and awareness in this area, especially in the Asia-Pacific region, including Malaysia. This paper reports the position of a Malaysian Working Group on some key issues surrounding gut microbiota in early life and its role in gut health and diseases, as well as experts' stand on probiotics and prebiotics. The group reached a consensus that certain factors, including elective caesarean; premature deliveries; complementary feeding; use of antibiotics, prebiotics and/or probiotics; and exposure to the external environmental, have an impact on gut microbiota in early life. However, as evidence is lacking, especially from the Asia-Pacific region, further studies are needed to understand how gut microbiota in early life affects subsequent diseases, including allergy, inflammatory bowel disease, obesity and infantile colic. Lastly, although beneficial in acute diarrhoeal disease and probably allergic eczema, probiotics (and/or prebiotics) should be used cautiously in other gut dysbiotic conditions until more data are available.

Sex-specific impact of asthma during pregnancy on infant gut microbiota

Asthma during pregnancy is associated with retardation of fetal growth in a sex-specific manner. Lactobacilli microbes influence infant growth. This study aimed to determine whether lactobacilli and other microbes are reduced in the gut of infants born to an asthmatic mother, and whether this differs by the sex of the infant.

Mother-infant pairs (N=1021) from the Canadian Healthy Infant Longitudinal Development full-term cohort were studied. The abundance of infant faecal microbiota at 3–4 months, profiled by gene sequencing, was compared between both women with and without asthma treatment during pregnancy. Infant sex, maternal ethnicity, pre-pregnancy overweight and atopy status, birth mode, breastfeeding status and intrapartum antibiotic treatment were tested as covariates.

Independent of birth mode and other covariates, male, Caucasian infants born to women with prenatal asthma harboured fewer lactobacilli in the gut at 3–4 months of age. If asthmatic mothers had pre-pregnancy overweight, the abundance of Lactobacillus in males was further reduced in the infant gut, whereas the microbiota of female infants was enriched with Bacteroidaceae. Similar differences in infant gut microbial composition according to maternal prenatal asthma status were also more evident among women with food or environmental allergies.

Gut lactobacilli were less abundant in male infants, but Bacteroidaceae were more abundant in female infants at 3–4 months of age, following maternal asthma during pregnancy.

Gut lactobacilli are less abundant at 3–4 months in male but not female infants following maternal prenatal asthmahttp://ow.ly/jXnl30fU9xH

Effect of antibiotic, probiotic, and human rotavirus infection on colonisation dynamics of defined commensal microbiota in a gnotobiotic pig model

We developed a gnotobiotic (Gn) pig model colonised with defined commensal microbiota (DMF) to provide a simplified and controlled system to study the interactions between intestinal commensals, antibiotics (ciprofloxacin, CIP), probiotics (Escherichia coli Nissle 1917, EcN) and virulent human rotavirus (VirHRV). The DMF included seven gut commensal species of porcine origin that mimic the predominant species in the infant gut. Gn piglets were divided into four groups: DMF control (non-treated), DMF+CIP (CIP treated), DMF+CIP+EcN (CIP/EcN treated), DMF+EcN (EcN treated) and inoculated orally with 10⁵ cfu of each DMF strain. The pig gut was successfully colonised by all DMF species and established a simplified bacterial community by post-bacteria colonisation day (PBCD) 14/post-VirHRV challenge day (PCD) 0. Overall, Bifidobacterium adolescentis was commonly observed in faeces in all groups and time points. At PCD0, after six days of CIP treatment (DMF+CIP), we observed significantly decreased aerobic and anaerobic bacteria counts especially in jejunum (P<0.001), where no DMF species were detected in jejunum by T-RFLP. Following HRV challenge, 100% of pigs in DMF+CIP group developed diarrhoea with higher diarrhoea scores and duration as compared to all other groups. However, only 33% of pigs treated with EcN plus CIP developed diarrhoea. EcN treatment also enhanced the bacterial diversity and all seven DMF species were detected with a higher proportion of Bifidobacterium longum in jejunum in the DMF+CIP+EcN group on PBCD14/PCD0. Our results suggest that EcN increased the proportion of B. longum especially in jejunum and mitigated adverse impacts of antibiotic use during acute-infectious diarrhoea. The DMF model with a simplified gut commensal community can further our knowledge of how commensals and probiotics promote intestinal homeostasis and contribute to host health.

Probiotics and Disease: A Comprehensive Summary-Part 7, Immune Disorders

This article series provides a literature review of the disease-specific probiotic strains associated with immune and autoimmune conditions that have been studied in published clinical trials in humans and animals. This is not an exhaustive review. The table design allows for quick access to supportive data and will be helpful as a guide for both researchers and clinicians. The goal of the probiotics and disease series is to provide clinically useful tools. The first article (part 1) focused on mental health and neurological conditions, and the second article (part 2) explored cultured and fermented foods that are commonly available in the United States. The third article (part 3) explored the relationship between bacterial strains and 2 of the most prevalent diseases we have in modern society: cardiometabolic disease and fatigue syndromes. The fourth article (part 4) elucidated the role of the microbiome in infectious diseases, and the fifth article (part 5) examined respiratory conditions of the ears, nose, and throat. The sixth article (part 6) explored the relationship between beneficial microbiota and skin disorders. This seventh article (part 7) reviews the relationship between beneficial microbiota and autoimmune diseases, allergies, asthma, and other immunity-related disorders. Future articles will review the relationship between probiotics and skin disorders, the influence of the microbiome on cancer development and prognosis, and gastrointestinal and genitourinary diseases associated with dysbiosis, followed by an article focused on probiotic supplements. This literature review is specific to disease condition, probiotic classification, and individual strain.