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Atopic dermatitis and food sensitization in South African toddlers
... Prevotella was the most common genus in older children (> 2 years) in our study; this is comparable to studies done in other developing countries 11,39,40 . A recent South African study that evaluated the association between diet and atopic dermatitis in children found that the higher abundance of Prevotella in healthy controls may indicate a protective effect against atopic dermatitis 18 . There was no depletion of Bacteroides, as has been noted in some child and adult studies in rural African communities 41,42 . ...
Differences in the microbiota in populations over age and geographical locations complicate cross-study comparisons, and it is therefore essential to describe the baseline or control microbiota in each population. This includes the determination of the influence of demographic, clinical and environmental factors on the microbiota in a setting, and elucidates possible bias introduced by these factors, prior to further investigations. Little is known about the microbiota of children in South Africa after infancy. We provide a detailed description of the gut microbiota profiles of children from urban Cape Town and describe the influences of various clinical and environmental factors in different age groups during the first 5 years of life. Prevotella was the most common genus identified in the participants, and after infancy, the gut bacteria were dominated by Firmicutes and Bacteroidetes. In this setting, children exposed to antibiotics and indoor cooking fires were at the most risk for dysbiosis, showing significant losses in gut bacterial diversity.
... A subsection of the rural cohort (47 children) were included as non-atopic controls in a study (36,47) comparing the diet and intestinal microbiome in Black African children with and without atopic dermatitis. Significantly lower sugar and saturated fat consumption was reported in the diets of rural children without AD than in their atopic counterparts and a significant association was found between higher consumption of sugar and AD. ...
Background:
The prevalence of allergic diseases differs in urban and rural populations.
Objective:
To assess associations between environmental and dietary factors with allergic diseases in urban and rural South African children.
Methods:
Toddlers aged 12-36 months were assessed for food- and aero-allergen sensitisation, atopic dermatitis, allergic rhinitis, asthma and challenge-proven food allergy. Information was collected on family history of allergic diseases, household size, socioeconomic status, delivery mode, antibiotic and probiotic use, exposure to fermented and unpasteurised milk, antihelminth treatment, sunlight exposure, pet and farm animal exposure, cigarette smoke and household cooking and heating fuels. Antenatal exposures to pets, livestock and cigarette smoke was assessed. A subsection completed questions on consumption of fruit/vegetables, fast foods, soft drinks/fruit juices and fried/microwaved meat.
Results:
Risk and protective factors differed between urban and rural settings. Exposure to farm animals in infants and their mothers during pregnancy was protective against allergic outcomes in the rural population. Consumption of unpasteurised milk is uncommon in this group of rural children and is unlikely to be an important factor in rural protection. In urban children birth by caesarean section is associated with food allergy and consumption of fermented milk products is associated with reduced asthma and atopic dermatitis. In both cohorts antenatal maternal smoking and environmental smoking exposure were predominantly associated with asthma and consumption of fast foods and fried meat were associated with allergy.
Conclusion:
In this rural environment exposure to livestock is the strongest protective factor. In urban communities, where animal contact is rare, risk factors include caesarian section and protective factors include consumption of fermented milk products. Modifiable risk factors urgently require interventions to prevent increasing allergies in countries undergoing rapid urbanization.
... Urban and rural diets differed significantly in many ways. 9 Energy intake and grams of protein, carbohydrates, fiber, simple sugars, and fat were significantly lower in rural South African children than in urban children. In addition, fiber and sugar intake was significantly lower in rural children compared to urban children. ...
This study describes and compares allergic diseases and sensitization in urban and rural children in the SAFFA study cohort as well as infant feeding patterns and nutritional status. We assessed the relationship between nutritional status, breastfeeding, complementary feeding patterns, and atopic diseases including aeroallergen and food allergen sensitization, self‐reported atopic dermatitis, allergic rhinitis, asthma, and challenge‐proven food allergy (FA).
Methodology
A total of 1185 urban and 398 rural toddlers aged 12‐36 months were screened for food sensitization (FS) and FA using skin prick testing and oral food challenges. Of these, 535 and 347, respectively, were additionally screened for aeroallergen sensitization. Information was collected on infant feeding practices, and anthropometric measurements and clinical signs for atopy were documented.
Results
Markedly higher rates of allergy (asthma 9.0% vs 1.0%, eczema 25.6% vs 2.0%, rhinitis 25.3% vs 3.3%, and FA 2.5% vs 0.5%) exist in urban vs rural children. 13.1% unselected urban South African children were sensitized to aeroallergens compared to 3.8% of their rural counterparts and 9.0% to any food compared to 0.5%. Exclusive breastfeeding duration was longer, and there was a later introduction of allergenic foods in rural communities. Obesity rates were similar between the two groups, but rural children were more likely to be stunted. Being overweight was associated with asthma in urban but not rural settings. In the urban cohort, children with FS and allergy were thinner than their peers.
Conclusion
Allergy and sensitization rates are significantly higher in unselected urban South African toddlers than their rural counterparts. Risk and protective factors for allergy and atopy may differ between urban and rural settings.
... 8,9 AD is strongly associated with the development of food allergy, bronchial asthma, and allergic rhinitis, commonly referred to as the Atopic March. [10][11][12][13][14][15] The epidermis provides a physical and functional barrier to the human body, and skin barrier defects are the most important pathologic findings in AD skin. 16-18 Skin barrier defects have been considered an initial step in developing AD. ...
The epidermis contains epithelial cells, immune cells, and microbes which provides a physical and functional barrier to the protection of human skin. It plays critical roles in preventing environmental allergen penetration into the human body and responsing to microbial pathogens. Atopic dermatitis (AD) is the most common, complex chronic inflammatory skin disease. Skin barrier dysfunction is the initial step in the development of AD. Multiple factors, including immune dysregulation, filaggrin mutations, deficiency of antimicrobial peptides, and skin dysbiosis contribute to skin barrier defects. In the initial phase of AD, treatment with moisturizers improves skin barrier function and prevents the development of AD. With the progression of AD, effective topical and systemic therapies are needed to reduce immune pathway activation and general inflammation. Targeted microbiome therapy is also being developed to correct skin dysbiosis associated with AD. Improved identification and characterization of AD phenotypes and endotypes are required to optimize the precision medicine approach to AD. © Copyright The Korean Academy of Asthma, Allergy and Clinical Immunology.
... Food and environmental allergens may play a role in refractory AD, but caution should be exercised when interpreting allergy testing and recommending food avoidance. [30][31][32][33] Patients with severe AD, particularly children, often have more food sensitization. However, food sensitization does not imply allergy without the correct clinical context. ...
Introduction
Atopic dermatitis (AD) is one of the most common chronic skin conditions affecting about 20% of children and 5% of adults. However, the studies assessing novel therapies for AD have been focused mainly on paediatric patients and only few studies have involved adult participants.
Aim
To compare the treatment outcomes between the antihistamine monotherapy and combined intervention with an antihistamine agent and a cysteinyl leukotriene receptor antagonist in adult patients with atopic dermatitis.
Material and methods
Patients were randomized into two groups to receive 5 mg oral desloratadine or the combined therapy with 5 mg oral desloratadine and 10 mg montelukast. Both groups were also administered topical treatment using the same protocol (topical Elocon and moisturizer). To estimate the efficacy of the implemented therapy methods, different skin health scores (SCORAD, GISS, EASI, PPNRS and DLQI) and skin functional assessment outcomes (corneometry, pH and transepidermal water loss) were evaluated before and after the treatment.
Results
Significant differences were revealed in compared measurement results for scales of the Extent and Severity of Eczema assessment, Global Individual Signs Score, Eczema Area and Severity Index, Pruritus Numerical Rating Scale, Dermatology Life Quality Index and Skin Functional Properties (p > 0.05).
Conclusions
Comparison of data presenting the therapy outcomes in two groups showed that administration of the combined therapy was significantly more effective compared to the antihistamine monotherapy. The results revealed considerable efficacy of the combined therapy reinforced by the use of cysteinyl leukotriene receptor antagonist, montelukast.
The gut microbiota has emerged as a key human health and disease determinant. However, there is a significant knowledge gap regarding the composition, diversity, and function of the gut microbiota, specifically in the African population. This scoping review aims to examine the existing literature on gut microbiota research conducted in Africa, providing an overview of the current knowledge and identifying research gaps. A comprehensive search strategy was employed to identify relevant studies. Databases including MEDLINE (PubMed), African Index Medicus (AIM), CINAHL (EBSCOhost), Science Citation index (Web of Science), Embase (Ovid), Scopus (Elsevier), WHO International Clinical Trials Registry Platform (ICTRP), and Google Scholar were searched for relevant articles. Studies investigating the gut microbiota in African populations of all age groups were included. The initial screening included a total of 2136 articles, of which 154 were included in this scoping review. The current scoping review revealed a limited number of studies investigating diseases of public health significance in relation to the gut microbiota. Among these studies, HIV (14.3%), colorectal cancer (5.2%), and diabetes mellitus (3.9%) received the most attention. The top five countries that contributed to gut microbiota research were South Africa (16.2%), Malawi (10.4%), Egypt (9.7%), Kenya (7.1%), and Nigeria (6.5%). The high number (n = 66) of studies that did not study any specific disease in relation to the gut microbiota remains a gap that needs to be filled. This scoping review brings attention to the prevalent utilization of observational study types (38.3%) in the studies analysed and emphasizes the importance of conducting more experimental studies. Furthermore, the findings reflect the need for more disease-focused, comprehensive, and population-specific gut microbiota studies across diverse African regions and ethnic groups to better understand the factors shaping gut microbiota composition and its implications for health and disease. Such knowledge has the potential to inform targeted interventions and personalized approaches for improving health outcomes in African populations.
Background
Gut microbiota plays an important role in the development of atopic dermatitis (AD). We aimed to elucidate research trends in gut microbiota and AD in children, to provide evidence and insights to the clinical prevention and treatment of AD in children.
Methods
A scoping literature review on the studies of gut microbiota and AD were conducted. Two authors independently searched Pubmed et al. databases for studies focused on gut microbiota and AD in children up to January 15, 2022. The literatures were screened and analyzed by two reviewers.
Results
A total of 44 reports were finally included and analyzed. Current researches have indicated that abnormal human microecology is closely associated with AD, and the disturbance of intestinal microbiota plays an important role in the occurrence and development of AD. Probiotics can correct the microbiota disorder, have the functions of regulating immunity, antioxidant, and help to restore the microecological homeostasis. However, there is still a lack of high-quality research reports on the efficacy and safety of probiotics in the prevention and treatment of AD in children.
Conclusions
The changes of gut microbiota are essential to the development of AD in children, which may be an effective target for the prevention and treatment of AD. Future studies with larger sample size and rigorous design are needed to elucidate the effects and safety of probiotics in AD.
This chapter reviews the literature regarding the role of intestinal microbes (flora and pathogens) in initiating autoimmunity. The chapter discusses mechanisms linking intestinal flora with autoimmunity. Some autoimmunity diseases will be described in detail including systemic lupus erythematous and psoriasis. Microbial therapeutics for halting and prevention of autoimmune disease will be discussed. Finally, this chapter made a focus on the crosstalk between intestinal microbiome and host and adaptive immunity.KeywordsIntestineFloraPathogensAutoimmuneCrosstalkMicrobiome
Background
The role of the human microbiome in health and disease is an emerging and important area of research; however, there is a concern that African populations are under-represented in human microbiome studies. We, therefore, conducted a systematic survey of African human microbiome studies to provide an overview and identify research gaps. Our secondary objectives were: (i) to determine the number of peer-reviewed publications; (ii) to identify the extent to which the researches focused on diseases identified by the World Health Organization [WHO] State of Health in the African Region Report as being the leading causes of morbidity and mortality in 2018; (iii) to describe the extent and pattern of collaborations between researchers in Africa and the rest of the world; and (iv) to identify leadership and funders of the studies.
Methodology
We systematically searched Medline via PubMed, Scopus, CINAHL, Academic Search Premier, Africa-Wide Information through EBSCOhost, and Web of Science from inception through to 1st April 2020. We included studies that characterized samples from African populations using next-generation sequencing approaches. Two reviewers independently conducted the literature search, title and abstract, and full-text screening, as well as data extraction.
Results
We included 168 studies out of 5515 records retrieved. Most studies were published in PLoS One (13%; 22/168), and samples were collected from 33 of the 54 African countries. The country where most studies were conducted was South Africa (27/168), followed by Kenya (23/168) and Uganda (18/168). 26.8% (45/168) focused on diseases of significant public health concern in Africa. Collaboration between scientists from the United States of America and Africa was most common (96/168). The first and/or last authors of 79.8% of studies were not affiliated with institutions in Africa. Major funders were the United States of America National Institutes of Health (45.2%; 76/168), Bill and Melinda Gates Foundation (17.8%; 30/168), and the European Union (11.9%; 20/168).
Conclusions
There are significant gaps in microbiome research in Africa, especially those focusing on diseases of public health importance. There is a need for local leadership, capacity building, intra-continental collaboration, and national government investment in microbiome research within Africa.
Sub-Saharan Africa (SSA) is currently undergoing a transformation process of unprecedented magnitude due to economic development and urbanization. This is paralleled by a dramatic increase in prevalence and incidence of non-communicable disease (NCDs). In this article we analyze the current situation with regard to one group of the earliest NCDs in life time, namely allergies and asthma. This article provides an update on epidemiology, availability, and access of management strategies to patients suffering from bronchial asthma or atopic dermatitis in SSA. Despite all progress, there is still a tremendous need to support education and training, transfer of resources, cooperation with pharmaceutical and diagnostic companies to achieve adequate treatment and sustainability in SSA with regard to allergy, asthma, and eczema management.
The prevalence of food allergy (FA) has been increasing over the past few decades; recent statistics suggest that FA has an impact on up to 10% of the population and 8% of children. Although the pathogenesis of FA is unclear, studies suggest gut microbiome plays a role in the development of FA. The gut microbiome is influenced by infant feeding method, infant diet, and maternal diet during lactation. Breastfeeding, Mediterranean diet, and probiotics are associated with commensal gut microbiota that protect against FA. This area of research is essential to discovering potential preventive methods or therapeutic targets against FA.
Background
Previous studies have shown that a child's risk of developing atopic disease is impacted by both genetic and environmental factors. Because small children spend the majority of their time in their homes, exposure to microbial factors in their home environment may be protective or risk factors for development of atopic diseases, such as atopic dermatitis.
Methods
Dust samples from the homes of 86 Black South African children 12 to 36 months old were collected for analysis of the bacterial microbiome. This case‐control study design included children with and without atopic dermatitis from rural and urban environments.
Results
Significant differences in bacterial composition and diversity were found when comparing children with and without atopic dermatitis. Furthermore, house dust microbiota was significantly different in rural and urban areas. Differences were best accounted for by higher relative abundance of Ruminococcaceae, Lachnospiraceae, and Bacteroidaceae families in rural compared with urban houses. Levels of Ruminococcaceae were also found to be significantly depleted in the house dust of rural children with atopic dermatitis as compared to control children.
Conclusions
House dust composition may be an important risk factor for the development of atopic disease, and this association may be driven in part by the gut microbiome. Low levels of the Ruminococcaceae family from Clostridia class in particular may explain the association between urban living and atopy. However, further research is needed to elucidate these links.
During the last decade, the advent of modern sequencing methods (next generation techniques, NGS) has helped describe the composition of the human gut microbiome, enabling us to understand the main characteristics of a healthy gut microbiome and, conversely, the magnitude of its disease-related changes. This new knowledge has revealed that healthy gut microbiota allow the maintenance of several crucial physiological functions, such as the ability to regulate the innate and adaptive immune systems. Increasing evidence has pointed out a condition of dysbiosis in several autoimmune/immune mediated dermatological conditions and specific gut microbial signatures have also been reported to correlate with clinical and prognostic parameters of such diseases. Based on a literature search of relevant published articles, this review debates the current knowledge and the possible pathogenic implications of bacterial gut microbiota composition assessed through NGS techniques in systemic lupus erythematosus, atopic dermatitis, psoriasis, and alopecia areata. Evidence of a potential role of specific gut microbiota signatures in modulating the clinical course of such diseases and their main comorbidities has been also reviewed.
Gut dysbiosis has been associated with several disease outcomes including diabetes in human populations. Currently, there are no studies of the gut microbiome composition in relation to type 2 diabetes (T2D) in Africans. Here, we describe the profile of the gut microbiome in non-diabetic adults (controls) and investigate the association between gut microbiota and T2D in urban West Africans. Gut microbiota composition was determined in 291 Nigerians (98 cases, 193 controls) using fecal 16S V4 rRNA gene sequencing done on the Illumina MiSeq platform. Data analysis of operational taxonomic units (OTU) was conducted to describe microbiome composition and identify differences between T2D and controls. The most abundant phyla were Firmicutes, Actinobacteria, and Bacteroidetes. Clostridiaceae, and Peptostreptococcaceaea were significantly lower in cases than controls (p < 0.001). Feature selection analysis identified a panel of 18 OTUs enriched in cases that included Desulfovibrio piger, Prevotella, Peptostreptococcus, and Eubacterium. A panel of 17 OTUs that was enriched in the controls included Collinsella, Ruminococcus lactaris, Anaerostipes, and Clostridium. OTUs with strain-level annotation showing the largest fold-change included Cellulosilyticum ruminicola (log2FC = −3.1; p = 4.2 × 10⁻⁵), Clostridium paraputrificum (log2FC = −2.5; p = 0.005), and Clostridium butyricum (log2FC = −1.76; p = 0.01), all lower in cases. These findings are notable because supplementation with Clostridium butyricum and Desulfovibrio piger has been shown to improve hyperglycemia and reduce insulin resistance in murine models. This first investigation of gut microbiome and diabetes in urban Africans shows that T2D is associated with compositional changes in gut microbiota highlighting the possibility of developing strategies to improve glucose control by modifying bacterial composition in the gut.
Food allergy (FA) is currently a significant health care problem in the developing world. Widely varying study populations and methodologies, the use of surrogate markers such as self report or hospitalization rates due to anaphylaxis rather than objective methods, limits robust estimation of FA prevalence in low income settings. Also, allergy is under-recognized as a clinical specialty in the developing world which compromises the chance for accurate diagnosis. In this review, most published data on food allergens from developing or low income countries are displayed. The diagnostic challenges and limitations of treatment options are discussed. It seems that FA is an under-appreciated health care issue in the developing world, and accurate determination of its burden in low-income settings represents an important unmet need. Multicenter surveillance studies, using standardized methodologies, are, therefore, needed to reveal the true extent of the problem and provide epidemiological clues for prevention. Preventive strategies should be tailored to fit local circumstances in different geographic regions. In addition, studying the gene environment interactions and impact of early life microbiota on the expression of FA in developing communities would be worthwhile. Efforts and resources should be directed toward public health education and training of health care providers dealing with food allergic patients. Keywords: Food allergy, Developing countries, Low income, Allergens, Diagnosis, Treatment, Unmet needs
Understanding the dietary intakes of infants and toddlers is important because early life nutrition influences future health outcomes. The aim of this study was to determine the dietary sources of total energy and 16 nutrients in a nationally representative sample of U.S. infants and toddlers aged 0-24 months. Data from the 2005-2012 National Health and Nutrition Examination Survey were analyzed. Dietary intake was assessed in 2740 subjects using one 24-h dietary recall. The population proportion was used to determine the contribution of foods and beverages to nutrient intakes. Overall infant formulas and baby foods were the leading sources of total energy and nutrients in infants aged 0-11.9 months. In toddlers, the diversity of food groups contributing to nutrient intakes was much greater. Important sources of total energy included milk, 100% juice and grain based mixed dishes. A number of foods of low nutritional quality also contributed to energy intakes including sweet bakery products, sugar-sweetened beverages and savory snacks. Overall non-flavored milks and ready-to-eat cereals were the most important contributors to micronutrient intakes. In conclusion this information can be used to guide parents regarding appropriate food selection as well as inform targeted dietary strategies within public health initiatives to improve the diets of infants and toddlers.
Little is known about the predictors of eczema severity in the US population.
We sought to determine the distribution and associations of childhood eczema severity in the United States.
We analyzed the data from the 2007 National Survey of Children's Health, a prospective questionnaire-based study of a nationally representative sample of 91,642 children (range, 0-17 years).
The prevalence of childhood eczema was 12.97% (95% confidence interval [95% CI], 12.42-13.53); 67.0% (95% CI, 64.8-69.2) had mild disease, 26.0% (95% CI, 23.9-28.1) had moderate disease, and 7.0% (95% CI, 5.8-8.3) had severe disease. There was significant statewide variation of the distribution of eczema severity (Rao-Scott χ, P = 0.004), with highest rates of severe disease in Mid-Atlantic and Midwestern states. In univariate models, eczema severity was increased with older age, African American and Hispanic race/ethnicity, lower household income, oldest child in the family, home with a single mother, lower paternal/maternal education level, maternal general health, maternal/paternal emotional health, dilapidated housing, and garbage on the streets. In multivariate survey logistic regression models using stepwise and backward selection, moderate-to-severe eczema was associated with older age, lower household income, and fair or poor maternal health but inversely associated with birthplace outside the United States.
These data indicate that environmental and/or lifestyle factors play an important role in eczema severity.
Increasing evidence suggests that perturbations in the intestinal microbiota composition of infants are implicated in the
pathogenesis of food allergy (FA), while the actual structure and composition of the intestinal microbiota in human beings
with FA remain unclear. Microbial diversity and composition were analyzed with parallel barcoded 454 pyrosequencing targeting
the 16S rRNA gene hypervariable V1-V3 regions in the feces of 34 infants with FA (17 IgE mediated and 17 non-IgE mediated)
and 45 healthy controls. Here, we showed that several key FA-associated bacterial phylotypes, but not the overall microbiota
diversity, significantly changed in infancy fecal microbiota with FA and were associated with the development of FA. The proportion
of abundant Bacteroidetes, Proteobacteria, and Actinobacteria phyla were significantly reduced, while the Firmicutes phylum was highly enriched in the FA group (P < 0.05). Abundant Clostridiaceae 1 organisms were prevalent in infants with FA at the family level (P = 0.016). FA-enriched phylotypes negatively correlated with interleukin-10, for example, the genera Enterococcus and Staphylococcus. Despite profound interindividual variability, levels of 20 predominant genera were significantly different between the FA
and healthy control groups (P < 0.05). Infants with IgE-mediated FA had increased levels of
Clostridium sensu stricto and Anaerobacter and decreased levels of Bacteroides and Clostridium XVIII (P < 0.05). A positive correlation was observed between Clostridium sensu stricto and serum-specific IgE (R = 0.655, P < 0.001). The specific microbiota signature could distinguish infants with IgE-mediated FA from non-IgE-mediated ones. Detailed
microbiota analysis of a well-characterized cohort of infants with FA showed that dysbiosis of fecal microbiota with several
FA-associated key phylotypes may play a pathogenic role in FA.
The prevalence of atopic eczema has been found to have increased greatly in some parts of the world. Building on a systematic review of global disease trends in asthma, our objective was to study trends in incidence and prevalence of atopic eczema. Disease trends are important for health service planning and for generating hypotheses regarding the aetiology of chronic disorders. We conducted a systematic search for high quality reports of cohort, repeated cross-sectional and routine healthcare database-based studies in seven electronic databases. Studies were required to report on at least two measures of the incidence and/or prevalence of atopic eczema between 1990 and 2010 and needed to use comparable methods at all assessment points. We retrieved 2,464 citations, from which we included 69 reports. Assessing global trends was complicated by the use of a range of outcome measures across studies and possible changes in diagnostic criteria over time. Notwithstanding these difficulties, there was evidence suggesting that the prevalence of atopic eczema was increasing in Africa, eastern Asia, western Europe and parts of northern Europe (i.e. the UK). No clear trends were identified in other regions. There was inadequate study coverage worldwide, particularly for repeated measures of atopic eczema incidence. Further epidemiological work is needed to investigate trends in what is now one of the most common long-term disorders globally. A range of relevant measures of incidence and prevalence, careful use of definitions and description of diagnostic criteria, improved study design, more comprehensive reporting and appropriate interpretation of these data are all essential to ensure that this important field of epidemiological enquiry progresses in a scientifically robust manner.
It is debated whether a low total diversity of the gut microbiota in early childhood is more important than an altered prevalence of particular bacterial species for the increasing incidence of allergic disease. The advent of powerful, cultivation-free molecular methods makes it possible to characterize the total microbiome down to the genus level in large cohorts.
We sought to assess microbial diversity and characterize the dominant bacteria in stool during the first year of life in relation to atopic eczema development.
Microbial diversity and composition were analyzed with barcoded 16S rDNA 454-pyrosequencing in stool samples at 1 week, 1 month, and 12 months of age in 20 infants with IgE-associated eczema and 20 infants without any allergic manifestation until 2 years of age (ClinicalTrials.gov ID NCT01285830).
Infants with IgE-associated eczema had a lower diversity of the total microbiota at 1 month (P = .004) and a lower diversity of the bacterial phylum Bacteroidetes and the genus Bacteroides at 1 month (P = .02 and P = .01) and the phylum Proteobacteria at 12 months of age (P = .02). The microbiota was less uniform at 1 month than at 12 months of age, with a high interindividual variability. At 12 months, when the microbiota had stabilized, Proteobacteria, comprising gram-negative organisms, were more abundant in infants without allergic manifestation (Empirical Analysis of Digital Gene Expression in R [edgeR] test: P = .008, q = 0.02).
Low intestinal microbial diversity during the first month of life was associated with subsequent atopic eczema.
Gut microbial composition depends on different dietary habits just as health depends on microbial metabolism, but the association of microbiota with different diets in human populations has not yet been shown. In this work, we compared the fecal microbiota of European children (EU) and that of children from a rural African village of Burkina Faso (BF), where the diet, high in fiber content, is similar to that of early human settlements at the time of the birth of agriculture. By using high-throughput 16S rDNA sequencing and biochemical analyses, we found significant differences in gut microbiota between the two groups. BF children showed a significant enrichment in Bacteroidetes and depletion in Firmicutes (P < 0.001), with a unique abundance of bacteria from the genus Prevotella and Xylanibacter, known to contain a set of bacterial genes for cellulose and xylan hydrolysis, completely lacking in the EU children. In addition, we found significantly more short-chain fatty acids (P < 0.001) in BF than in EU children. Also, Enterobacteriaceae (Shigella and Escherichia) were significantly underrepresented in BF than in EU children (P < 0.05). We hypothesize that gut microbiota coevolved with the polysaccharide-rich diet of BF individuals, allowing them to maximize energy intake from fibers while also protecting them from inflammations and noninfectious colonic diseases. This study investigates and compares human intestinal microbiota from children characterized by a modern western diet and a rural diet, indicating the importance of preserving this treasure of microbial diversity from ancient rural communities worldwide.
Intestinal microbiota undergoes substantial development during the first 2 years of life, important for intestinal immunologic development and maturation influencing systemic immune responses.
We aimed to investigate, using a prospective study design, whether allergen-specific IgE (sIgE) and atopic eczema are associated with variations in gut microbial colonization patterns in an unselected population during the first 2 years of life.
Faeces from 94 infants were repeatedly sampled from 10 days, 4 months, 1 and 2 years postnatal and analysed for 12 different bacterial species by quantitative real-time PCR. Venous blood samples from the infants were collected at 2 years of age and were analysed for sIgE for 12 specific allergens. The temporal gut colonization patterns for 42 sIgE-positive (sIgE≥0.35 kU/L) and 52 sIgE-negative children (sIgE<0.1 kU/L) were then compared. The association between colonization pattern and phenotype as atopic eczema according to UK Working Party (UKWP) criteria were also described.
Subjects with atopic sensitization had lower levels of Escherichia coli at 4 months and 1 year, higher levels of Bifidobacterium longum at 1 year and lower levels of Bacteroides fragilis at 2 years. For E. coli and B. longum, the differences were only transient and had disappeared by 2 years of age. For other species, there were no differences in colonization patterns, and we found no association between colonization pattern and atopic eczema.
We found temporal and transient variations in gut microbial colonization patterns associated with differences in sIgE sensitization at 2 years of age. A full understanding of the principles and mechanisms that underlie intestinal microbial colonization and diversity and host-microbiota relationships will be pivotal for the development of therapeutic approaches that manipulate the intestinal microbiota to maintain human health. [Registration number: ISRCTN28090297].
Hay fever has been described as a "post industrial
revolution epidemic,"' and successive morbidity
surveys from British general practice suggest that its
prevalence has continued to increase over the past 30
years.) Other evidence suggests a recent increase in the
prevalence of asthma2 and childhood eczema.3 This
paper suggests a possible explanation for these trends
over time.
Exposure to specific bacterial bowel commensals may increase/reduce the risk of atopic diseases.
To compare fecal bacterial communities of young infants with/without eczema.
Nested case-control study. Infants age 3 to 6 months with eczema (cases, n = 37) and without (controls, n = 24) were matched for sex, age, feeding (breast/bottle/mixed/solids), ethnicity. Information was collected on maternal/infant antibiotic exposure, feeding, gastrointestinal symptoms, family history of allergy. Eczema severity scoring was used (Severity Scoring of Atopic Dermatitis index). Samples were taken for determination of allergen-specific serum IgE (cases) and urinary/fecal eosinophilic protein X. Gastrointestinal permeability was measured. The compositions of fecal bacterial communities were analyzed (culture-independent, nucleic acid-based analyses).
There was no difference in overall profiles of fecal bacterial communities between cases and controls. Family history of allergy increased likelihood of bifidobacteria detection (history, 86%; no history, 56%; P = .047); breast-fed infants were more likely to harbor Bifidobacterium bifidum (odds ratio, 5.19; 95% CI, 1.47-18.36; P = .01). Bifidobacterium pseudocatenulatum was detected more commonly in feces of non-breast-fed children (odds ratio, 5.6; 95% CI, 1.3-24.3; P = .02) and children with eczema (eczema, 26%; no eczema, 4%; P = .04). There were no significant associations between clinical measurements and detection of B pseudocatenulatum.
Presence of B pseudocatenulatum in feces was associated with eczema and with exclusive formula-feeding; B bifidum was associated with breast-feeding.