Association of Early Life Exposure to Antibiotics With Risk of Atopic Dermatitis in Sweden

Prevalence of systemic antibacterial use during pregnancy worldwide: A systematic review

OBJECTIVES

In this study, we aimed to systematically review the literature of the prevalence of systemic antibacterial use during pregnancy and to perform a descriptive analysis focused on methodological characteristics.

MATERIALS AND METHODS

This study was registered in PROSPERO under protocol number CRD42022376634. Medline, Embase, Scientific Electronic Library Online, Biblioteca Virtual em Saúde, Cumulative Index to Nursing and Allied Health Literature, and Web of Science databases were searched (published studies until November 3rd, 2022). Selected studies were population-based cross-sectional or cohort, carried out with pregnant women, and providing information about the prevalence of systemic antibacterial use at least in one trimester of pregnancy. Reviewers conducted in pairs the title and abstract screening, eligibility criteria check, and data extraction of selected studies. Quality appraisal was performed with an adapted version of the Joanna Briggs Institute Critical Appraisal Checklist for Prevalence Studies. Data of included studies were pooled into a graphical and tabular summary.

RESULTS

A total of 16,251,280 pregnant women and 5,169,959 pregnancy registers were identified. The prevalence estimates of systemic antibacterial use during pregnancy ranged from 2.0% (95%CI 2.0-2.0) to 64.3% (95%CI not reported) in the 79 included studies. The majority were performed in high-income countries (91.5%). Overall, the studies revealed considerable prevalence heterogeneity in terms of study type and dataset used. The 95% confidence intervals were not reported in 41% of studies.

CONCLUSION

The disparities in the prevalence of systemic antibacterial use during pregnancy can be related to methodological issues and different health policies. Lack of uniform databases and changes in data collection methods over time should be taken into account in public health strategy planning. The scarce evidence in low- and middle-income settings hampers the comprehensiveness of the global prevalence of antibacterial use during pregnancy.

Reduction of Antibiotic-Associated Conditions After Tympanostomy Tube Placement in Children

OBJECTIVE

Tympanostomy tube placement has been shown to decrease systemic antibiotics usage in patients with recurrent acute otitis media. Systemic antibiotics in children are associated with an increase in antibiotic-associated conditions (asthma, allergic rhinitis, food allergy, atopic dermatitis, celiac disease, overweight/obesity, attention-deficit hyperactivity disorder [ADHD], autism, learning disability, and Clostridium difficile colonization) later in life. The objective of this study is to estimate whether tympanostomy tube placement is associated with a reduction in antibiotic-associated conditions in children with recurrent acute otitis media (RAOM).

METHODS

A retrospective cohort review of electronic medical records from 1991 to 2011 at a large pediatric hospital system was performed identifying 27,584 patients under 18 years old with RAOM, defined by 3 or more episodes of AOM. Antibiotic-associated conditions were defined using ICD-9 and ICD-10 codes.

RESULTS

The enrollment population was largely composed of White patients (28.9%), Black patients (30.1%), and Hispanic/Latino patients (16.4%). The number of systemic antibiotics prescribed per encounter was significantly lower in children who pursued tympanostomy tubes (0.14 antibiotics per encounter) versus those who did not (0.23 antibiotics per encounter) (p < 0.001). Patients with RAOM who received tympanostomy tubes were less likely to have diagnoses of overweight/obesity (OR. 0.62 [0.55, 0.68]; p < 0.001), asthma (OR 0.8 [0.74, 0.87]; p < 0.001), allergic rhinitis (OR 0.72 [0.65, 0.81]; p < 0.001), and atopic dermatitis (0.78 [0.71, 0.86]; p < 0.001).

CONCLUSIONS AND RELEVANCE

Tympanostomy tube placement is associated with less systemic antibiotic administration and a decreased incidence of overweight/obesity, asthma, allergic rhinitis, and atopic dermatitis in children diagnosed with RAOM.

LEVEL OF EVIDENCE

4 Laryngoscope, 2024.

Global prevalence of antibiotic consumption during pregnancy: A systematic review and meta-analysis

BACKGROUND

Antibiotic use during pregnancy is widespread with notable variations across regions.

METHODS

This systematic review and meta-analysis (Prospero protocol CRD42023418979) examines the prevalence and variability of antibiotic use in pregnancy globally and regionally, considering different methodologies and maternal characteristics. We searched Embase, PubMed, and Web of Science for observational studies published in English from the year 2000 and onwards. Random-effect meta-analyses were used to pool the prevalence of antibiotic consumption during pregnancy, presented as percentages with 95% confidence intervals (CI). Joanna Briggs Institute Critical appraisal checklist for prevalence studies was used for bias assessment.

FINDINGS

Overall, 116 studies (14 from Africa, 24 from the Americas, six from Eastern Mediterranean, 57 from Europe, four from South-East Asia and 11 from Western Pacific) were included (33,821,194 pregnancies). The majority of studies (84.5%) were appraised with a low risk of bias. The prevalence of antibiotic consumption during pregnancy ranged between 0.04 to 90%, with a pooled estimate of 23.6% (95% CI: 20.1-27.5, I2 =100%). Low-income countries had the highest pooled prevalence (45.3%, 95% CI: 15.4-79.1, I2 =99.6%). Regionally, the Western Pacific had the highest pooled prevalence (34.4%, 95% CI: 13.4-64.1, I2 =100%). The prevalence of antibiotic consumption during pregnancy increased over time in the Americas and Western Pacific. The studies exhibited considerable heterogeneity (I2 >95%), and the trim-and-fill method estimated a potential 10% underestimation of the overall pooled prevalence, suggesting publication bias.

INTERPRETATION

This meta-analysis suggests that about 1/4 of women worldwide use antibiotics during pregnancy. This study suggests a high prevalence of antibiotic consumption during pregnancy with disparities according to region and level of country income, ethnicity and whether antibiotics were prescribed or self-medicated. There was a variability in reported findings across age categories, potential bias from small sample sizes, and language bias from including only studies published in English.

Race science without racists: how bigoted paradigms persist in allergy research

In the wake of the murder of George Floyd and the massacre in Buffalo, the editorial boards of the prominent scientific publication companies formally apologized for their journals' historical role in advancing race science and promised to improve their standards. However, flowery commentaries cannot undo the consistent pattern of endorsing biologic differences between ethnic groups, even when discussing diseases or traits that are not considered politically charged. In this report, an exemplar is made of a recent publication claiming to identify phenotypes of atopic dermatitis that are distinct between European Americans, Asians, and African Americans. The insufficiency of the evidence and logic underlying these claims are discussed. Although devoid of malice, numerous publications continue to demonstrate how claims of biological differences between races is mainstreamed in modern scientific publications. Overall, the goal of this work is to challenge the scientific community, particularly the publication companies, to evaluate how assumptions of innate biologic disadvantage have clouded assessments of racial disparities in disease beyond the topics that are more stereotypical of race science.

Antibiotics taken within the first year of life are linked to infant gut microbiome disruption and elevated atopic dermatitis risk

BACKGROUND

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in both pediatric and adult populations. The development of AD has been linked to antibiotic usage, which causes perturbation of the microbiome and has been associated with abnormal immune system function. However, imbalances in the gut microbiome itself associated with antibiotic usage have been inconsistently linked to AD.

OBJECTIVES

This study aimed to elucidate the timing and specific factors mediating the relationship between systemic (oral or intravenous) antibiotic usage and AD.

METHODS

We used statistical modeling and differential analysis to link CHILD Cohort Study participants' history of antibiotic usage and early-life gut microbiome alterations to AD.

RESULTS

Here we report that systemic antibiotics during the first year of life, as compared to later, are associated with AD risk (adjusted odds ratio [aOR] = 1.81; 95% CI: 1.28-2.57; P < .001), with an increased number of antibiotic courses corresponding to a dose response-like increased risk of AD risk (1 course: aOR: 1.67; 95% CI: 1.17-2.38; 2 or more courses: aOR: 2.16; 95% CI: 1.30-3.59). Further, we demonstrate that microbiome alterations associated with both AD and systemic antibiotic usage fully mediate the effect of antibiotic usage on the development of AD (βindirect = 0.072; P < .001). Alterations in the 1-year infant gut microbiome of participants who would later develop AD included increased Tyzzerella nexilis, increased monosaccharide utilization, and parallel decreased Bifidobacterium and Eubacterium spp, and fermentative pathways.

CONCLUSIONS

These findings indicate that early-life antibiotic usage, especially in the first year of life, modulates key gut microbiome components that may be used as markers to predict and possibly prevent the development of AD.

In utero or early-in-life exposure to antibiotics and the risk of childhood atopic dermatitis, a population-based cohort study

BACKGROUND

Atopic dermatitis (AD) is a common inflammatory disease of the skin that begins early in life and can be lifelong. The purpose of our study was to evaluate whether fetal exposure and/or early-life exposure of a child to antibiotics increases the risk of early-onset AD.

OBJECTIVES

We hypothesize that antibiotic exposure in utero or early in life (e.g. first 90 days) increases the likelihood that children develop AD.

METHODS

Utilizing a large, prospectively collected electronic medical records database, we studied the association of antibiotic exposure received in utero or very early in life and the relative risk of onset of AD in a population-based cohort study. Associations were estimated using proportional hazards models as hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

The risk of AD in childhood was increased after in utero or early-life antibiotic exposure. For any in utero antibiotic exposure the HR (CI) was 1.38 (1.36-1.39). However, penicillin demonstrated the strongest association with AD for both in utero exposure [1.43 (1.41-1.44)] and for childhood exposure [1.81 (1.79-1.82)]. HRs were higher in children born to mothers without AD than in those with AD pointing to effect modification by maternal AD status.

CONCLUSIONS

Children born to mothers exposed to antibiotics while in utero had, depending on the mother's history of AD, approximately a 20-40% increased risk of developing AD. Depending on the antibiotic, children who received antibiotics early in life had a 40-80% increased risk of developing AD. Our study supports and refines the association between incident AD and antibiotic administration. It also adds population-based support to therapeutic attempts to treat AD by modifying the skin microbiome.

The skin microbiome in pediatric atopic dermatitis and food allergy

The skin microbiome is an extensive community of bacteria, fungi, mites, viruses and archaea colonizing the skin. Fluctuations in the composition of the skin microbiome have been observed in atopic dermatitis (AD) and food allergy (FA), particularly in early life, established disease, and associated with therapeutics. However, AD is a multifactorial disease characterized by skin barrier aberrations modulated by genetics, immunology, and environmental influences, thus the skin microbiome is not the sole feature of this disease. Future research should focus on mechanistic understanding of how early-life skin microbial shifts may influence AD and FA onset, to guide potential early intervention strategies or as microbial biomarkers to identify high-risk infants who may benefit from possible microbiome-based biotherapeutic strategies. Harnessing skin microbes as AD biotherapeutics is an emerging field, but more work is needed to investigate whether this approach can lead to sustained clinical responses.

Epidemiologic and Clinical Clues to the Etiology of Eosinophilic Esophagitis

Despite the rising prevalence and incidence of eosinophilic esophagitis (EoE), the etiology and pathophysiology remain unknown. Studies to date suggest that complex interactions between genetic and environmental risk factors result in the development and presentation of disease. Examining environmental factors both in the early life and later life exposures offers potential clues for the development of EoE, although challenges exist in making causal inferences due to diagnostic delay and access, ascertainment biases, and misclassification of cases. The authors review studies supporting early life factors as etiologic factors in the development of EoE.

The microbiome-gut-brain axis in nutritional neuroscience

Emerging evidence is highlighting the microbiome as a key regulator of the effect of nutrition on gut-brain axis signaling. Nevertheless, it is not yet clear whether the impact of nutrition is moderating the microbiota-gut-brain interaction or if diet has a mediating role on microbiota composition and function to influence central nervous system function, brain phenotypes and behavior. Mechanistic evidence from cell-based in vitro studies, animal models and preclinical intervention studies are linking the gut microbiota to the effects of diet on brain function, but they have had limited translation to human intervention studies. While increasing evidence demonstrates the triangulating relationship between diet, microbiota, and brain function across the lifespan, future mechanistic and translational studies in the field of microbiota and nutritional neuroscience are warranted to inform potential strategies for prevention and management of several neurological, neurodevelopmental, neurodegenerative, and psychiatric disorders. This brief primer provides an overview of the most recent advances in the nutritional neuroscience - microbiome field, highlighting significant opportunities for future research.

The Interaction between the Host Genome, Epigenome, and the Gut-Skin Axis Microbiome in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease that occurs in genetically predisposed individuals. It involves complex interactions among the host immune system, environmental factors (such as skin barrier dysfunction), and microbial dysbiosis. Genome-wide association studies (GWAS) have identified AD risk alleles; however, the associated environmental factors remain largely unknown. Recent evidence suggests that altered microbiota composition (dysbiosis) in the skin and gut may contribute to the pathogenesis of AD. Examples of environmental factors that contribute to skin barrier dysfunction and microbial dysbiosis in AD include allergens, irritants, pollution, and microbial exposure. Studies have reported alterations in the gut microbiome structure in patients with AD compared to control subjects, characterized by increased abundance of Clostridium difficile and decreased abundance of short-chain fatty acid (SCFA)-producing bacteria such as Bifidobacterium. SCFAs play a critical role in maintaining host health, and reduced SCFA production may lead to intestinal inflammation in AD patients. The specific mechanisms through which dysbiotic bacteria and their metabolites interact with the host genome and epigenome to cause autoimmunity in AD are still unknown. By understanding the combination of environmental factors, such as gut microbiota, the genetic and epigenetic determinants that are associated with the development of autoantibodies may help unravel the pathophysiology of the disease. This review aims to elucidate the interactions between the immune system, susceptibility genes, epigenetic factors, and the gut microbiome in the development of AD.

Maternal exposure to antibiotics and risk of atopic dermatitis in childhood: a systematic review and meta-analysis

Background

Although the association between maternal exposure to antibiotics and the risk of atopic dermatitis (AD) in childhood has been studied extensively, there still is a lack of clarity on the topic. The aim of this study was to summarize the published data and to examine if maternal exposure to antibiotics increases the risk of AD in childhood.

Methods

Systematic search was performed in PubMed, Scopus, Web of Science, and Embase for all types of studies on the review subject independent of any language restrictions and published up to 28th December 2022. Data was analyzed using random-effects model and presented as pooled odds ratio (OR) with 95% confidence intervals (CI).

Results

A total of 18 studies (5,354,282 mother-child pairs) were included. Maternal exposure to antibiotics was associated with an increased risk of AD in childhood (OR: 1.14, 95% CI: 1.06, 1.22, I²= 85%, p = 0.0003). The significance of the results was not affected by the location of the study (Asia or Europe). While subgroup analysis based on exposure assessment or diagnosis of AD demonstrated a tendency of increased risk of AD, the association was not statistically significant in multiple subgroups. Segregating data based on the timing of exposure did not affect the significance of the results for studies on all trimesters. However, there was no association between antibiotic exposure in the third trimester or just before delivery and the risk of childhood AD.

Conclusion

The results of this meta-analysis suggest that maternal exposure to antibiotics may lead to a modestly increased risk of AD in offspring. The evidence is limited by high interstudy heterogeneity and bias in exposure and outcome assessment. Future studies are needed to explore if the timing of exposure, the dose, the number of prescriptions, and the type of antibiotic affect this association.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023387233.

Prenatal and early-life antibiotic exposure and the risk of atopic dermatitis in children: A nationwide population-based cohort study

BACKGROUND

Atopic dermatitis (AD) contributes to substantial social and financial costs in public health care systems. Antibiotic exposure during pregnancy has been proposed as a risk factor, but findings remain inconsistent. The aim of this study was to investigate the association between prenatal antibiotic use and childhood AD.

METHODS

We performed a population-based cohort study using data collected from the Taiwan Maternal and Child Health Database from 2009 to 2016. Associations were determined using Cox proportional hazards model and were adjusted for several potential covariates, including maternal atopic disorders and gestational infections. Children with and without maternal predispositions of atopic diseases and postnatal antibiotic/acetaminophen exposures within 1 year were stratified to identify the subgroups at risk.

RESULTS

A total of 1,288,343 mother-child pairs were identified and 39.5% received antibiotics prenatally. Maternal antibiotic use during pregnancy was slightly positively associated with childhood AD (aHR 1.04, 95% CI 1.03-1.05), especially in the first and second trimesters. An apparent dose-response pattern was observed with an 8% increased risk when the exposure was ≥5 courses prenatally (aHR 1.08, 95% CI 1.06-1.11). Subgroup analysis showed the positive association remained significant regardless of postnatal infant antibiotic use, but the risk attenuated to null in infants who were not exposed to acetaminophen (aHR 1.01, 95% CI 0.96-1.05). The associations were higher in children whose mothers were without AD compared to those whose mothers were with AD. In addition, postnatal antibiotic or acetaminophen exposure of infants was associated with an increased risk of developing AD after 1 year of age.

CONCLUSION

Maternal antibiotic use during pregnancy was associated with an increased risk of childhood AD in a dose-related manner. Further research may be warranted to investigate this variable using a prospectively designed study, and also to examine whether or not this association is specifically related to pregnancy.

The Imprint of Exposome on the Development of Atopic Dermatitis across the Lifespan: A Narrative Review

Atopic dermatitis (AD) is a chronic inflammatory skin condition that affects more than 200 million people worldwide, including up to 20% of children and 10% of the adult population. Although AD appears frequently in childhood and often continues into adulthood, about 1 in 4 adults develop the adult-onset disease. The prenatal period, early childhood, and adolescence are considered critical timepoints for the development of AD when the exposome results in long-lasting effects on the immune system. The exposome can be defined as the measure of all the exposures of an individual during their lifetime and how these exposures relate to well-being. While genetic factors could partially explain AD onset, multiple external environmental exposures (external exposome) in early life are implicated and are equally important for understanding AD manifestation. In this review, we describe the conceptual framework of the exposome and its relevance to AD from conception and across the lifespan. Through a spatiotemporal lens that focuses on the multi-level phenotyping of the environment, we highlight a framework that embraces the dynamic complex nature of exposome and recognizes the influence of additive and interactive environmental exposures. Moreover, we highlight the need to understand the developmental origins of AD from an age-related perspective when studying the effects of the exposome on AD, shifting the research paradigm away from the per se categorized exposome factors and beyond clinical contexts to explore the trajectory of age-related exposome risks and hence future preventive interventions.

Bacterial Metabolites: A Link between Gut Microbiota and Dermatological Diseases

Dysbiosis has been identified in many dermatological conditions (e.g., psoriasis, atopic dermatitis, systemic lupus erythematosus). One of the ways by which the microbiota affect homeostasis is through microbiota-derived molecules (metabolites). There are three main groups of metabolites: short-chain fatty acids (SCFAs), tryptophan metabolites, and amine derivatives including trimethylamine N-oxide (TMAO). Each group has its own uptake and specific receptors through which these metabolites can exert their systemic function. This review provides up-to-date knowledge about the impact that these groups of gut microbiota metabolites may have in dermatological conditions. Special attention is paid to the effect of microbial metabolites on the immune system, including changes in the profile of the immune cells and cytokine disbalance, which are characteristic of several dermatological diseases, especially psoriasis and atopic dermatitis. Targeting the production of microbiota metabolites may serve as a novel therapeutic approach in several immune-mediated dermatological diseases.

Exposure to isocyanates predicts atopic dermatitis prevalence and disrupts therapeutic pathways in commensal bacteria

Atopic dermatitis (AD) is a chronic inflammatory skin condition increasing in industrial nations at a pace that suggests environmental drivers. We hypothesize that the dysbiosis associated with AD may signal microbial adaptations to modern pollutants. Having previously modeled the benefits of health-associated Roseomonas mucosa, we now show that R. mucosa fixes nitrogen in the production of protective glycerolipids and their ceramide by-products. Screening EPA databases against the clinical visit rates identified diisocyanates as the strongest predictor of AD. Diisocyanates disrupted the production of beneficial lipids and therapeutic modeling for isolates of R. mucosa as well as commensal Staphylococcus. Last, while topical R. mucosa failed to meet commercial end points in a placebo-controlled trial, the subgroup who completed the full protocol demonstrated sustained, clinically modest, but statistically significant clinical improvements that differed by study site diisocyanate levels. Therefore, diisocyanates show temporospatial and epidemiological association with AD while also inducing eczematous dysbiosis.

Is Atopic Dermatitis Only a Skin Disease?

Atopic dermatitis (AD) is a chronic, pruritic, inflammatory dermatosis that imposes significant patient and population burdens. In addition to the cutaneous signs and symptoms, growing evidence suggests that AD is systemic in nature. Certain diseases can possibly co-occur with AD as a result of coincidental exposure to similar environmental factors. However, it is also suspected that they are linked to the pathogenesis of AD through more complex genetic and immunological mechanisms, but these correlations remain less understood. It is of great need to seek explanations for the higher frequency of the number of cardiovascular, autoimmune, neurological, psychiatric, and metabolic disorders that have been observed in epidemiologic investigations among AD patients. Moreover, analysing the immunology of chronic inflammation and its correction, activation, or suppression may prevent the development of a variety of comorbidities. As comorbid diseases in patients diagnosed with AD may potentially go undetected, physicians should be aware of them.

Mode of delivery and offspring atopic dermatitis in a Swedish nationwide study

BACKGROUND

Atopic dermatitis is a common chronic childhood disease associated with significant morbidity and healthcare costs. There is a known association between caesarean section and asthma, but the relationship between caesarean section and offspring atopic dermatitis remains uncertain.

METHODS

We conducted a register-based nationwide cohort study including children born in Sweden between January 2006 and December 2018. Data on health and socioeconomic variables were extracted from the national registers for children aged ≤5 years. Time-to-event analyses were used to calculate hazard ratios (HR) with 95% confidence intervals (CI) adjusting for confounders and familial factors.

RESULTS

1,399,406 children were included (6,029,542 person-years at risk). Atopic dermatitis was observed in 17.2% of the 1,150,896 children born by vaginal delivery and 18.3% of the 248,510 born by caesarean section. The mean age of onset of atopic dermatitis was 2.72 years (SD 1.8). Birth by caesarean section was associated with a higher risk of atopic dermatitis (adj-HR 1.12, 95% CI: 1.10-1.14). A higher risk of atopic dermatitis was found in children born by instrumental vaginal delivery (adj-HR 1.10, 1.07-1.13); emergency caesarean section (adj-HR 1.12, 1.10-1.15), and elective caesarean section (adj-HR 1.13, 1.10-1.16) than uncomplicated vaginal delivery in children <1 year of age. Similar hazards were observed in those ≥1 year of age. In sibling control analysis, greater risks remained in children aged <1 year but not in age ≥1 year.

CONCLUSIONS

In our study population, it was observed that children born by caesarean section or instrumental vaginal delivery were at higher risk of early childhood atopic dermatitis. Although familial confounding attenuates the risk in children aged ≥1 year, this was not observed in the first year of life.

A cohort study of intrapartum group B streptococcus prophylaxis on atopic dermatitis in 2-year-old children

OBJECTIVE

To understand the occurrence of atopic dermatitis (AD) in children aged 2 years on exposure to maternal group B streptococcus (GBS) antibiotic prophylaxis (IAP).

DESIGN

Retrospective cohort study of 2909 mother-child pairs.

SETTING

Taixing People's Hospital in Eastern China.

PARTICIPANTS

Term infants born 2018-2019, followed longitudinally from birth to 2 years.

EXPOSURES

The GBS-IAP was defined as therapy with intravenous penicillin G or ampicillin or cefazolin ≥ 4 h prior to delivery to the mother. Reference infants were defined as born without or with other intrapartum antibiotic exposure.

OUTCOMES

The logistic regression models were employed to analyze the effect of intrapartum GBS prophylaxis on AD in 2-year-old children during delivery. Analysis was a priori stratified according to the mode of delivery and adjusted for relevant covariates.

RESULTS

The cohorts showed that preventive GBS-IAP was potentially associated with increased incidence of AD in children delivered vaginally according to logistic regression models before and after covariate-adjusted treatment (OR: 6.719,95% CI: 4.730-9.544,P < 0.001;aOR: 6.562,95% CI: 4.302-10.008, P < 0.001).

CONCLUSION

Prophylactic treatment of intrapartum GBS may raise the risk of AD in vaginally delivered children. These findings highlight the need to better understand the risk between childhood AD and current GBS-IAP intervention strategies.

Maladaptive consequences of inflammatory events shape individual immune identity

The vertebrate immune system develops in layers, as modes of immunity have evolved on top of each other through time with the expansion of organismal complexity. The maturation timing of immune cell subsets, such as innate immune cells, innate-like cells and adaptive cells, corresponds to their physiological roles in protective immunity. While various cell subsets have specialized roles, they also complement each other to clear pathogens, resolve inflammation and maintain homeostasis, especially at barrier sites with high microbial density. Immune cells adapt to inflammatory insults through mechanisms including epigenetic and metabolic reprogramming, clonal expansion and enhanced communication with the surrounding tissue environment. Over time, these adaptations shape an individual immune identity, reflective of the overlay between the genetic predisposition and the antigenic and environmental exposures of each individual. While some aspects of this immune shaping are natural consequences of immune maturation over time, others are maladaptive and predispose to irreversible pathology. In this Perspective, we provide a framework for categorizing the shaping events of the immune response, in terms of mechanisms, contexts and functional outcomes. We aim to clarify how these terms can be appropriately applied to future findings that impact immune function.

Meta-analysis of early-life antibiotic use and allergic rhinitis

This meta-analysis aimed to investigate the correlation between early-life antibiotic use and allergic rhinitis. PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases were searched for available studies. Eighteen studies covering 1,768,874 children were included. Early-life antibiotics were associated with an increased incidence of allergic rhinitis (effect size (ES) = 5.00, 95% confidence interval [CI]: 4.88-5.13; I 2 = 95.7%, P heterogeneity <0.001). In Asia, Europe, and the USA, the incidence of allergic rhinitis in the antibiotic group was higher than that in the no medication group (Asia: ES = 3.68, 95% CI: 3.38-4.01; Europe: ES = 3.20, 95% CI: 3.00-3.42; USA: ES = 3.68, 95% CI: 2.74-4.95). Compared with the no medication group, children who received antibiotics in the first 1 week of life (ES = 5.75, 95% CI: 2.18-15.18), first 1 year of life (ES = 3.37, 95% CI: 3.20-3.55; I 2 = 64.2%, P heterogeneity = 0.001), or first 3 years of life (ES = 5.21, 95% CI: 2.42-11.19) had a higher incidence of allergic rhinitis. No individual study influenced the estimates of the meta-analysis. The funnel plot showed moderate symmetry and low publication bias. In conclusion, the use of antibiotics in early life was associated with allergic rhinitis. Still, most included studies analyzed antibiotic exposure as a dichotomous variable, without information on the type and dosage of antibiotics.

Prior hospital-based infection and risk of eosinophilic esophagitis in a Swedish nationwide case-control study

BACKGROUND AND AIMS

Eosinophilic esophagitis (EoE) is an increasingly common, largely food allergen-driven disease characterized by dysphagia. Prior infections are known to associate with other loss of tolerance diseases such as autoimmunity. We aimed to determine if antecedent infection was associated with later EoE development.

METHODS

We performed a case-control study of all patients with biopsy-verified EoE diagnosed between 2000 and 2017 in Sweden (n = 1587) and matched to 5 general population controls (n = 7660). Cases were identified using histopathology codes from the Epidemiology Strengthened by histopathology Reports in Sweden study, a validated cohort of gastrointestinal pathology reports from all 28 pathology centers in Sweden. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals for antecedent infections from patients seen at hospital-based outpatient clinics or inpatients. In secondary analyses, we compared EoE patients with their full siblings to further reduce residual confounding.

RESULTS

564 (35.7%) EoE patients and 1793 (23.4%) matched controls had an earlier record of infection. This corresponded to a 2-fold increased risk of infections in EoE patients (OR 2.01; 95%CI: 1.78-2.27). ORs for earlier gastrointestinal or respiratory infection were 2.73 (n = 128 EoE, 268 control; 95%CI: 2.17-3.41) and 1.89 (n = 305 EoE, 960 control; 95%CI: 1.63-2.20), respectively. Having an EoE diagnosis was linked to a 3.39-fold increased odds of sepsis (n = 14 EoE, 21 control; 95%CI: 1.68-6.65). Individuals with EoE were also more likely to have had an infection compared to their non-EoE siblings (n = 427 EoE, 593 control; OR = 1.57; 95%CI = 1.30-1.89).

CONCLUSION

In this nationwide cohort study, prior infection, was associated with subsequent EoE. Risks were particularly high after sepsis, and gastrointestinal or respiratory infections.

Controlling skin microbiome as a new bacteriotherapy for inflammatory skin diseases

The skin serves as the interface between the human body and the environment and interacts with the microbial community. The skin microbiota consists of microorganisms, such as bacteria, fungi, mites, and viruses, and they fluctuate depending on the microenvironment defined by anatomical location and physiological function. The balance of interactions between the host and microbiota plays a pivotal role in the orchestration of skin homeostasis; however, the disturbance of the balance due to an alteration in the microbial communities, namely, dysbiosis, leads to various skin disorders. Recent developments in sequencing technology have provided new insights into the structure and function of skin microbial communities. Based on high-throughput sequencing analysis, a growing body of evidence indicates that a new treatment using live bacteria, termed bacteriotherapy, is a feasible therapeutic option for cutaneous diseases caused by dysbiosis. In particular, the administration of specific bacterial strains has been investigated as an exclusionary treatment strategy against pathogens associated with chronic skin disorders, whereas the safety, efficacy, and sustainability of this therapeutic approach using isolated live bacteria need to be further explored. In this review, we summarize our current understanding of the skin microbiota, as well as therapeutic strategies using characterized strains of live bacteria for skin inflammatory diseases. The ecosystem formed by interactions between the host and skin microbial consortium is still largely unexplored; however, advances in our understanding of the function of the skin microbiota at the strain level will lead to the development of new therapeutic methods.

Early-life exposure to antibiotics and subsequent development of atopic dermatitis

BACKGROUND

Antibiotic exposure may be associated with atopic dermatitis (AD). The objective of the study is to examine the risk of developing AD among children exposed early to antibiotics.

RESEARCH DESIGN AND METHODS

From the Italian Pedianet database, children aged 0-14 years between 2004-2017 were enrolled from birth up to at least one year. Cox proportional-hazards models were fitted to estimate Hazard Ratios (HR) and 95% Confidence Intervals (CI) for the association between antibiotic exposure during the first year of life with incident AD. Exposure was also considered as a time-varying variable.

RESULTS

73,816 children were included in the final cohort, of which 34,202 had at least one antibiotic prescription. Incident AD was present in 8% of unexposed and exposed children. Early antibiotic exposure was not associated with any excess risk of AD compared to unexposed children (HR: 1.02, 95% CI: 0.97-1.07), and no dose-response effect was observed. In the time-varying analysis, antibiotic exposure was significantly associated with AD onset (1.12, 1.07-1.17). However, when taking into account the time-lag between exposure and outcome, risks progressively decreased, suggesting possible protopathic bias.

CONCLUSION

These results are not suggestive of any significant association between exposure to antibiotics and subsequent AD onset and support the possible presence of protopathic bias.

Association of Prenatal Antibiotics and Mode of Birth With Otolaryngology Surgery in Offspring: A National Data Linkage Study

BACKGROUND

Pediatric otolaryngology surgery is commonly performed after recurrent infections and allergy/atopy. Prenatal antibiotic exposure and cesarean section deliveries increase the risk of severe infection and allergy/atopy in the offspring, but the relationship with common, related surgical outcomes is unknown. This study measures the associations between prenatal antibiotic use and mode of birth with common pediatric otolaryngology surgery.

METHODS

Data linkage analysis of all live-born, singleton children, born between 2008 and 2018 was done using Norwegian national health registry data. Exposures of interest were prenatal antibiotics and mode of birth. The primary outcome was common otolaryngology surgery before 10 years of age. Exposure-outcome associations were estimated through multivariable Cox proportional hazards models adjusting for predefined covariates. Interaction between exposures was explored.

RESULTS

Of 539,390 children, 146,832 (27.2%) had mothers who were prescribed antibiotics during pregnancy, 83,473 (15.5%) were delivered via cesarean section, and 48,565 (9.0%) underwent an otolaryngology surgery during the study period. Prenatal antibiotic exposure [adjusted hazard ratio (aHR), 1.22; 95% CI: 1.20-1.24] and cesarean section (aHR, 1.14; 95% CI: 1.11-1.16) were each associated with otolaryngology surgery after mutual adjustment. There was some evidence of an interaction between the 2 exposures (P = 0.03).

CONCLUSIONS

Antibiotic exposure in pregnancy and cesarean section may adversely affect early immune development and increase the risk of recurrent upper airway infections and allergy/atopy that may require otolaryngology surgery. Mechanistic studies are warranted to explore genetic and/or molecular pathways that explain these findings. This may identify potential therapeutic targets to reduce the burden of otolaryngology surgery.

Large-scale health insurance study showed that antibiotic use in infancy was associated with an increase in atopic dermatitis

AIM

This retrospective large-scale study examined the association between prescribing antibiotics for infants and subsequent atopic dermatitis (AD).

METHODS

The data covered the period from 1 January 2005 to 31 December 2014 and were extracted from a Japanese health insurance claims database. The exposure was being prescribed antibiotics at less than 12 months of age and the outcome was a subsequent diagnosis of AD. The primary analysis method was multivariable Cox proportional hazard regression analysis. A sibling-matched analysis was also performed to adjust for shared familial and environmental confounders.

RESULTS

This study comprised 85 954 infants: 8654 (10.1%) who had received antibiotics and 77 300 who had not. AD was diagnosed in 1183 (13.7%) and 10 325 (13.4%) infants respectively. The exposed group was more likely to develop AD than the non-exposed group, but this association disappeared when we carried out the secondary, sibling-matched analysis of the two groups. Other risk factors for AD were macrolides, aminoglycosides, food allergies and histamine H1 receptor antagonists.

CONCLUSION

Antibiotic use in infancy was associated with a subsequent increase in the incidence of AD. This association should be considered when prescribing antibiotics, but antibiotic use may not be a critical factor for the development of AD.

Ruminococcus gnavus ameliorates atopic dermatitis by enhancing Treg cell and metabolites in BALB/c mice

BACKGROUND

Ruminococcus gnavus (R. gnavus) are mucin-degrading gut bacteria that play a key role in the early colonization of the gut by serving as endogenous sources of nutrients. They can also influence immune development. We had previously reported a lower abundance of R. gnavus in infants with atopic dermatitis (AD) compared with that in healthy subjects. However, the underlying mechanisms remain unclear. In this study, we investigated the effect of orally administered R. gnavus on antibiotic treatment-induced gut dysbiosis (and the underlying mechanism) in a mouse model of AD.

METHODS

Four-week-old female BALB/C mice were administered antibiotic cocktails for 2 weeks. R. gnavus was orally administered throughout the study duration. At 6 weeks of age, AD was induced by epidermal sensitization with ovalbumin. AD phenotypes and systemic and gut immune responses were investigated.

RESULTS

Orally administered R. gnavus significantly reduced AD-associated parameters (i.e., transepidermal water loss, clinical score, total serum immunoglobulin (Ig) E level, OVA-specific IgE level, and skin inflammation). R. gnavus treatment also resulted in significant downregulation of T helper 2-related cytokine mRNA and upregulation of interleukin (IL)-10 and Foxp3 in the skin. The population of CD4⁺ FOXP3⁺ T cells in mesenteric- and skin-draining lymph nodes and butyrate levels in the cecum increased in R. gnavus-administered AD mice.

CONCLUSIONS

Immune modulation by orally administered R. gnavus may alleviate AD symptoms through the enhancement of regulatory T-cell counts and short-chain fatty acids production in AD mice.

Azithromycin pretreatment exacerbates atopic dermatitis in trimellitic anhydride-induced model mice accompanied by correlated changes in the gut microbiota and serum cytokines

Atopic dermatitis (AD) is a common inflammatory skin disease. This study aims to investigate the effect of azithromycin (AZI) pretreatment, a common macrolide-type antibiotic, on the trimellitic anhydride (TMA) induced AD-like symptoms in mice. AZI (25 mg/kg, once daily, 5 days) was administered intragastrically before the 10-day TMA challenge. AD-like symptoms were assessed by ear thickening, scratching behavior, and pathological or immunofluorescence staining; Cytokines in the skin tissue and serum were measured by cytometric bead array; and the compositions of gut microbiota were assessed by 16S rRNA gene sequencing. AZI pretreatment accelerated the development of ear thickening and enhanced the severity of developed AD-like symptoms. AZI pretreatment promoted the infiltrations of neutrophil-like cells, T cells, and mast cells in ear skin. AZI pretreatment elevated the levels of IL-4, IL-6, and IL-17A in the ear skin of AD model mice, but it increased serum TNF-α and IL-6. AZI-pretreatment increased four gut bacterial genera (Bacteroides, Candidatus_Saccharibacteria_unclassified, Acetatifactor, Firmicutes_unclassified) but depleted three short-chain fatty acids producing gut bacterial genera (Alistipes, Clostridiales_unclassified, Butyricicoccus). AD-associated symptoms were positively associated with skin IL-4 and IL-17A, serum TNF-α, and IL-6, and Acetatifactor, but they negatively correlated to the three decreased gut bacterial genera (Alistipes, Clostridiales_unclassified, Butyricicoccus). Thus, our results demonstrate that AZI exposure deteriorates TMA-induced AD-like symptoms in mice, which is related to the imbalances of gut microbiota and skin/serum cytokines.