Antibiotic treatment of pregnant non-obese diabetic mice leads to altered gut microbiota and intestinal immunological changes in the offspring

Perturbed maternal microbiota shapes offspring microbiota during early colonization period in mice

Recent studies have highlighted the impact of disrupted maternal gut microbiota on the colonization of offspring gut microbiota, with implications for offspring developmental trajectories. The extent to which offspring inherit the characteristics of altered maternal gut microbiota remains elusive. In this study, we employed a mouse model where maternal gut microbiota disruption was induced using non-absorbable antibiotics. Systematic chronological analyses of dam fecal samples, offspring luminal content, and offspring gut tissue samples revealed a notable congruence between offspring gut microbiota profiles and those of the perturbed maternal gut microbiota, highlighting the profound influence of maternal microbiota on early-life colonization of offspring gut microbiota. Nonetheless, certain dominant bacterial genera in maternal microbiota did not transfer to the offspring, indicating a bacterial taxonomy-dependent mechanism in the inheritance of maternal gut microbiota. Our results embody the vertical transmission dynamics of disrupted maternal gut microbiota in an animal model, where the gut microbiota of an offspring closely mirrors the gut microbiota of its mother.

Maternal-driven immune education in offspring

Maternal environmental exposures, particularly during gestation and lactation, significantly influence the immunological development and long-term immunity of offspring. Mammalian immune systems develop through crucial inputs from the environment, beginning in utero and continuing after birth. These critical developmental windows are essential for proper immune system development and, once closed, may not be reopened. This review focuses on the mechanisms by which maternal exposures, particularly to pathogens, diet, and microbiota, impact offspring immunity. Mechanisms driving maternal-offspring immune crosstalk include transfer of maternal antibodies, changes in the maternal microbiome and microbiota-derived metabolites, and transfer of immune cells and cytokines via the placenta and breastfeeding. We further discuss the role of transient maternal infections, which are common during pregnancy, in providing tissue-specific immune education to offspring. We propose a "maternal-driven immune education" hypothesis, which suggests that offspring can use maternal encounters that occur during a critical developmental window to develop optimal immune fitness against infection and inflammation.

Antibiotic Resistance in Plant Pathogenic Bacteria: Recent Data and Environmental Impact of Unchecked Use and the Potential of Biocontrol Agents as an Eco-Friendly Alternative

The economic impact of phytopathogenic bacteria on agriculture is staggering, costing billions of US dollars globally. Pseudomonas syringae is the top most phytopathogenic bacteria, having more than 60 pathovars, which cause bacteria speck in tomatoes, halo blight in beans, and so on. Although antibiotics or a combination of antibiotics are used to manage infectious diseases in plants, they are employed far less in agriculture compared to human and animal populations. Moreover, the majority of antibiotics used in plants are immediately washed away, leading to environmental damage to ecosystems and food chains. Due to the serious risk of antibiotic resistance (AR) and the potential for environmental contamination with antibiotic residues and resistance genes, the use of unchecked antibiotics against phytopathogenic bacteria is not advisable. Despite the significant concern regarding AR in the world today, there are inadequate and outdated data on the AR of phytopathogenic bacteria. This review presents recent AR data on plant pathogenic bacteria (PPB), along with their environmental impact. In light of these findings, we suggest the use of biocontrol agents as a sustainable, eco-friendly, and effective alternative to controlling phytopathogenic bacteria.

From womb to world: mapping gut microbiota-related health literacy among Italian mothers, a cross-sectional study

BACKGROUND

The gut microbiota is a key determinant of long-term health. Promoting maternal health literacy may enhance children well-being. Aim of the present study was to assess gut microbiota-related health literacy of Italian women and identify potential gaps in awareness.

METHODS

A cross-sectional survey study was conducted using an online questionnaire (17 questions) on determinants and long-term impact of infant gut microbiota. The survey targeted Italian pregnant women and mothers of children under 2 years old, and was distributed through various social media channels between September 28th and November 15th, 2022. A total score was calculated as the sum of positive answers. Data on demographics, pregnancy status, and pre-existing knowledge of the infant gut microbiota were also collected. Descriptive and inferential statistics were applied.

RESULTS

The questionnaire was completed by 1076 women. Median total score was 9 [7-11]. The 81.7% of respondents declared prior knowledge of the gut microbiota. The internet was among the most commonly cited primary sources of information. Independent predictors of total score were having a university degree (B = 0.656, p = 0.002) and prior knowledge (B = 2.246, p < 0.001). Conversely, older age was associated with lower total scores (B = -0.092, p < 0.001). The least known determinants of infant gut microbiota were gestational BMI, prematurity, mode of delivery and NICU stay. Pregnant women failed to recognize the role of breastfeeding in the development of infant gut microbiota more frequently than non-pregnant women. The 97.5% of participants reported increased interest in the gut microbiota, with heightened interest associated with prior knowledge.

CONCLUSIONS

Our study revealed a moderate level of knowledge about infant gut microbiota among respondents, emphasizing the positive impact of prior knowledge on understanding and interest. Targeted educational interventions are needed to address awareness gaps, especially concerning the influence of breastfeeding on infant gut microbiota. Healthcare providers have the potential to enhance women's knowledge and awareness of this topic.

Maternal antibiotic exposure and childhood allergies: The Japan Environment and Children's Study

Background

The association of maternal antibiotic exposure during pregnancy with childhood allergic diseases remains unclear.

Objective

We aimed to evaluate the association of maternal exposure to antibiotic use during pregnancy with childhood allergic diseases up to the age of 3 years by using data from a large Japanese birth cohort.

Methods

We analyzed data on 78,678 pregnant women and their offspring aged 0 to 3 years. Prenatal antibiotic exposure was defined as the use of any antimicrobial agent during pregnancy. Information was collected from maternal interviews and medical record transcripts. The outcome variables in this study included preschool asthma, wheezing, food allergy, atopic dermatitis, eczema, allergic rhinoconjunctivitis, and any allergic disease. We used logistic regression analysis to evaluate the association of antibiotic exposure during pregnancy with childhood allergic diseases.

Results

Among the participating mothers, 28.5% used antibiotics during pregnancy. Antibiotic exposure during pregnancy was associated with preschool asthma (adjusted odds ratio [aOR] = 1.12 [95% CI = 1.06-1.19]), wheezing (aOR = 1.11 [95% CI = 1.07-1.15]), allergic rhinoconjunctivitis (aOR = 1.10 [95% CI = 1.03-1.17]) and any allergic disease (aOR = 1.09 [95% CI = 1.05-1.14]) in offspring up to age 3 years. In contrast, maternal antibiotic use was not associated with food allergies, atopic dermatitis, or eczema. Additionally, the significant associations were not influenced by the timing of antibiotic exposure, sex of the infants, or maternal history of allergies.

Conclusion

Maternal antibiotic exposure during pregnancy is associated with an increased risk of childhood respiratory allergies.

Infant gut microbiota colonization: influence of prenatal and postnatal factors, focusing on diet

Maternal microbiota forms the first infant gut microbial inoculum, and perinatal factors (diet and use of antibiotics during pregnancy) and/or neonatal factors, like intra partum antibiotics, gestational age and mode of delivery, may influence microbial colonization. After birth, when the principal colonization occurs, the microbial diversity increases and converges toward a stable adult-like microbiota by the end of the first 3-5 years of life. However, during the early life, gut microbiota can be disrupted by other postnatal factors like mode of infant feeding, antibiotic usage, and various environmental factors generating a state of dysbiosis. Gut dysbiosis have been reported to increase the risk of necrotizing enterocolitis and some chronic diseases later in life, such as obesity, diabetes, cancer, allergies, and asthma. Therefore, understanding the impact of a correct maternal-to-infant microbial transfer and a good infant early colonization and maturation throughout life would reduce the risk of disease in early and late life. This paper reviews the published evidence on early-life gut microbiota development, as well as the different factors influencing its evolution before, at, and after birth, focusing on diet and nutrition during pregnancy and in the first months of life.

Prenatal and Perinatal Antibiotic Exposure and Long-Term Outcome

Antibiotics are frequently administered during pregnancy. Although necessary to address acute infections, their use facilitates antibiotic resistance. Other associations have also been found with the use of antibiotics, such as perturbations of gut bacteria, delays in microbial maturation, and increased risks of allergic and inflammatory diseases. Little is known about how the prenatal and perinatal administration of antibiotics to mothers affects the clinical outcomes of their offspring. A literature search was conducted of the Cochrane, Embase, and PubMed engines. The retrieved articles were reviewed by two authors and verified for relevance. The primary outcome was the effect of pre- and perinatal maternal antibiotic use on clinical outcomes. Thirty-one relevant studies were included in the meta-analysis. Various aspects are discussed, including infections, allergies, obesity, and psychosocial factors. In animal studies, antibiotic intake during pregnancy has been suggested to cause long-term alterations in immune regulation. In humans, associations have been found between antibiotic intake during pregnancy and different types of infections and an increased risk of pediatric infection-related hospitalization. A dose-dependent positive association between pre- and perinatal antibiotic use and asthma severity has been reported in animal and human studies, while positive associations with atopic dermatitis and eczema were reported by human studies. Multiple associations were identified between antibiotic intake and psychological problems in animal studies; however, relevant data from human studies are limited. However, one study reported a positive association with autism spectrum disorders. Multiple animal and human studies reported a positive association between pre- and perinatal antibiotic use by mothers and diseases in their offspring. Our findings have potentially significant clinical relevance, particularly considering the implications for health during infancy and later in life as well as the related economic burden.

Comprehensive characterization of maternal, fetal, and neonatal microbiomes supports prenatal colonization of the gastrointestinal tract

In this study, we aimed to comprehensively characterize the microbiomes of various samples from pregnant women and their neonates, and to explore the similarities and associations between mother-neonate pairs, sample collection sites, and obstetrical factors. We collected samples from vaginal discharge and amniotic fluid in pregnant women and umbilical cord blood, gastric liquid, and meconium from neonates. We identified 19,597,239 bacterial sequences from 641 samples of 141 pregnant women and 178 neonates. By applying rigorous filtering criteria to remove contaminants, we found evidence of microbial colonization in traditionally considered sterile intrauterine environments and the fetal gastrointestinal track. The microbiome distribution was strongly grouped by sample collection site, rather than the mother-neonate pairs. The distinct bacterial composition in meconium, the first stool passed by newborns, supports that microbial colonization occurs during normal pregnancy. The microbiome in neonatal gastric liquid was similar, but not identical, to that in maternal amnionic fluid, as expected since fetuses swallow amnionic fluid in utero and their urine returns to the fluid under normal physiological conditions. Establishing a microbiome library from various samples formed only during pregnancy is crucial for understanding human development and identifying microbiome modifications in obstetrical complications.

Crosstalk between Gut Microbiota and Host Immunity: Impact on Inflammation and Immunotherapy

Gut microbes and their metabolites are actively involved in the development and regulation of host immunity, which can influence disease susceptibility. Herein, we review the most recent research advancements in the gut microbiota-immune axis. We discuss in detail how the gut microbiota is a tipping point for neonatal immune development as indicated by newly uncovered phenomenon, such as maternal imprinting, in utero intestinal metabolome, and weaning reaction. We describe how the gut microbiota shapes both innate and adaptive immunity with emphasis on the metabolites short-chain fatty acids and secondary bile acids. We also comprehensively delineate how disruption in the microbiota-immune axis results in immune-mediated diseases, such as gastrointestinal infections, inflammatory bowel diseases, cardiometabolic disorders (e.g., cardiovascular diseases, diabetes, and hypertension), autoimmunity (e.g., rheumatoid arthritis), hypersensitivity (e.g., asthma and allergies), psychological disorders (e.g., anxiety), and cancer (e.g., colorectal and hepatic). We further encompass the role of fecal microbiota transplantation, probiotics, prebiotics, and dietary polyphenols in reshaping the gut microbiota and their therapeutic potential. Continuing, we examine how the gut microbiota modulates immune therapies, including immune checkpoint inhibitors, JAK inhibitors, and anti-TNF therapies. We lastly mention the current challenges in metagenomics, germ-free models, and microbiota recapitulation to a achieve fundamental understanding for how gut microbiota regulates immunity. Altogether, this review proposes improving immunotherapy efficacy from the perspective of microbiome-targeted interventions.

Rural Embodiment and Community Health: an Anthropological Case Study on Biocultural Determinants of Tropical Disease Infection and Immune System Development in the USA

Purpose of Review

Biocultural methods are critically important for identifying environmental and socioeconomic factors linked with tropical disease risk and outcomes. For example, embodiment theory refers to the process by which lived experiences impact individual biology. Increased exposure to pathogens, chronic psychosocial stress, and unequal resource access are all outcomes linked with discrimination and poverty. Through lived experiences, race and socioeconomic inequality can literally become embodied-get under the skin and affect physiology-impacting immune responses and contributing to lifelong health disparities. Yet, few studies have investigated tropical disease patterns and associated immune function using embodiment theory to understand lasting physiological impacts associated with living in a high-pathogen environment.

Recent Findings

Here, we use preliminary data drawn from the Rural Embodiment and Community Health (REACH) study to assess whether pathogen exposure and immune stimulation within a sample of children from the Mississippi Delta are associated with household income. We also test whether immune marker levels-assessed with enzyme-linked immunosorbent assays using dried blood spot samples-vary between the REACH sample and a similarly aged nationally representative NHANES sample. Immune marker levels did not differ significantly between REACH participants living below vs. above the federal poverty line, yet immunoglobulin E levels-a marker of macroparasite infection-were higher among REACH study participants compared to the NHANES sample.

Summary

These results may suggest community-level pathogenic exposures (i.e., parasitic infections) are embodied by REACH participants with implications for long-term immune function, potentially resulting in immune aspects that differ from nationally representative samples.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40475-023-00282-z.

Comparison of obstetric to institutional antibiogram as an approach to advance antimicrobial stewardship in maternal care

OBJECTIVE

To create an antibiogram derived exclusively from our obstetric population and compare the clinical isolates and susceptibilities to our institutional antibiogram.

METHODS

Data collected by the University Hospital Clinical Microbiology Laboratory in SSC Soft from 01/01/2018 to 12/31/2018 was used to generate our institutional antibiogram. For comparison, we created an obstetric (OB) antibiogram using all clinical isolates collected during the same time interval from OB triage, labor & delivery, antepartum and postpartum wards. The antibiotic susceptibilities of the OB clinical isolates were compared to the institutional clinical isolates.

RESULTS

In total, we identified 929 clinical isolates from our OB population in 2018. Urine was the predominant source of clinical isolates (76.3%). The remaining sources included wound (10.1%), genital (9.0%), blood and other fluids (4.6%). Escherichia coli (E. coli) accounted for nearly half of all isolates (48.7%) followed by Group B Streptococcus (10.7%), Enterococcus spp. (9%), and Klebsiella pneumoniae (7.2%). There was no difference in susceptibilities of Gram-positive organisms in the OB antibiogram compared to the institutional antibiogram. Conversely, common Gram-negative organisms demonstrated less antibiotic resistance in the OB antibiogram compared to the institutional antibiogram. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were significantly more susceptible in the OB antibiogram compared to the institutional antibiogram to most antimicrobials tested.

CONCLUSION

Compared to our institutional antibiogram, gram-negative clinical isolates in our OB population exhibit less antibiotic resistance. Creation of an OB-specific antibiogram, which more accurately reflects antibiotic resistance patterns within our unique patient population, may promote appropriate antimicrobial use by assisting in more informed antibiotic selection and limit unnecessary use of broad-spectrum antibiotics.

Host-microbiota interactions shaping T-cell response and tolerance in type 1 diabetes

Type-1 Diabetes (T1D) is a complex polygenic autoimmune disorder involving T-cell driven beta-cell destruction leading to hyperglycemia. There is no cure for T1D and patients rely on exogenous insulin administration for disease management. T1D is associated with specific disease susceptible alleles. However, the predisposition to disease development is not solely predicted by them. This is best exemplified by the observation that a monozygotic twin has just a 35% chance of developing T1D after their twin’s diagnosis. This makes a strong case for environmental triggers playing an important role in T1D incidence. Multiple studies indicate that commensal gut microbiota and environmental factors that alter their composition might exacerbate or protect against T1D onset. In this review, we discuss recent literature highlighting microbial species associated with T1D. We explore mechanistic studies which propose how some of these microbial species can modulate adaptive immune responses in T1D, with an emphasis on T-cell responses. We cover topics ranging from gut-thymus and gut-pancreas communication, microbial regulation of peripheral tolerance, to molecular mimicry of islet antigens by microbial peptides. In light of the accumulating evidence on commensal influences in neonatal thymocyte development, we also speculate on the link between molecular mimicry and thymic selection in the context of T1D pathogenesis. Finally, we explore how these observations could inform future therapeutic approaches in this disease.

Models for Gut-Mediated Horizontal Gene Transfer by Bacterial Plasmid Conjugation

The emergence of new antimicrobial resistant and virulent bacterial strains may pose a threat to human and animal health. Bacterial plasmid conjugation is a significant contributor to rapid microbial evolutions that results in the emergence and spread of antimicrobial resistance (AR). The gut of animals is believed to be a potent reservoir for the spread of AR and virulence genes through the horizontal exchange of mobile genetic elements such as plasmids. The study of the plasmid transfer process in the complex gut environment is limited due to the confounding factors that affect colonization, persistence, and plasmid conjugation. Furthermore, study of plasmid transfer in the gut of humans is limited to observational studies, leading to the need to identify alternate models that provide insight into the factors regulating conjugation in the gut. This review discusses key studies on the current models for in silico, in vitro, and in vivo modeling of bacterial conjugation, and their ability to reflect the gut of animals. We particularly emphasize the use of computational and in vitro models that may approximate aspects of the gut, as well as animal models that represent in vivo conditions to a greater extent. Directions on future research studies in the field are provided.

An Updated Narrative Mini-Review on the Microbiota Changes in Antenatal and Post-Partum Depression

Background: Antenatal depression (AND) and post-partum depression (PPD) are long-term debilitating psychiatric disorders that significantly influence the composition of the gut flora of mothers and infants that starts from the intrauterine life. Not only does bacterial ratio shift impact the immune system, but it also increases the risk of potentially life-threatening disorders. Material and Methods: Therefore, we conducted a narrative mini-review aiming to gather all evidence published between 2018–2022 regarding microflora changes in all three stages of pregnancy. Results: We initially identified 47 potentially eligible studies, from which only 7 strictly report translocations; 3 were conducted on rodent models and 4 on human patients. The remaining studies were divided based on their topic, precisely focused on how probiotics, breastfeeding, diet, antidepressants, exogenous stressors, and plant-derived compounds modulate in a bidirectional way upon behavior and microbiota. Almost imperatively, dysbacteriosis cause cognitive impairments, reflected by abnormal temperament and personality traits that last up until 2 years old. Thankfully, a distinct technique that involves fecal matter transfer between individuals has been perfected over the years and was successfully translated into clinical practice. It proved to be a reliable approach in diminishing functional non- and gastrointestinal deficiencies, but a clear link between depressive women’s gastrointestinal/vaginal microbiota and clinical outcomes following reproductive procedures is yet to be established. Another gut-dysbiosis-driving factor is antibiotics, known for their potential to trigger inflammation. Fortunately, the studies conducted on mice that lack microbiota offer, without a shadow of a doubt, insight. Conclusions: It can be concluded that the microbiota is a powerful organ, and its optimum functionality is crucial, likely being the missing puzzle piece in the etiopathogenesis of psychiatric disorders.

Comparison and prioritization of antibiotics in a reservoir and its inflow rivers of Beijing, China

The occurrence of antibiotics in drinking water resources, like reservoirs, is of considerable concern due to their potential risks to ecosystem, human health, and antimicrobial resistance development. Here, we quantified 83 antibiotics in water and sediments of wet and dry seasons from the Miyun reservoir and its inflow rivers in Beijing, China. Twenty-four antibiotics were detected in water with concentrations of ND-11.6 ng/L and 19 antibiotics were observed in sediments with concentrations of ND-6.50 ng/g. Sulfonamides (SAs) were the dominated antibiotics in water in two seasons. SAs and quinolones (QNs) in wet season and macrolides (MLs) and QNs in dry season predominated in sediments. The reservoir and inflow rivers showed significant differences in antibiotic concentrations and compositions in water and sediments. As an important input source of reservoir, the river water showed significantly higher total antibiotic concentrations than those in the reservoir. In contrast, the reservoir sediments are the sink of antibiotics, and had higher total antibiotic concentrations compared with rivers. A prioritization approach based on the overall risk scores and detection frequencies of antibiotics was developed, and 3 (sulfaguanidine, anhydroerythromycin, and sulfamethoxazole) and 5 (doxycycline, sulfadiazine, clarithromycin, roxithromycin, and flumequine) antibiotics with high and moderate priority, respectively, were screened. The study provides a comprehensive insight of antibiotics in the Miyun Reservoir and its inflow rivers, and is significant for future monitoring and pollution mitigation of antibiotics.

Maternal antibiotics exposure during pregnancy and the risk of acute lymphoblastic leukemia in childhood: a systematic review and meta-analysis

Many epidemiological studies have assessed the association between maternal antibiotic exposure during pregnancy and childhood acute lymphoblastic leukemia (ALL), while reaching inconsistent conclusions. In order to clarify the association, the publications in English that provided information about maternal antibiotic exposure during pregnancy and ALL risk in offspring in the PubMed, Embase, and Web of Science databases were systematically reviewed and we performed a meta-analysis using the random-effect models. Results of pooled analysis showed that maternal antibiotic intake during pregnancy is not associated with childhood ALL risk (pooled odds ratio 1.07, 95% confidence interval 0.98-1.18) without significant heterogeneity (I² = 13.7%, P = 0.310). This finding was consistent across subgroups stratified by type of study design, measurement method, sample size, study quality, and pregnancy stage. Our findings suggest that maternal antibiotic consumption during pregnancy was not associated with ALL risk in progeny. Further investigations are needed to confirm the results and assess any risk differences of ALL by types of antibiotics.Conclusions: Our findings suggest that maternal antibiotics consumption during pregnancy was not associated with ALL risk in progeny. Further investigations are needed to confirm the results and assess any risk differences of ALL by types of antibiotics. What is Known: • It is not unusual for pregnant woman to receive antibiotics for local or systematic use during pregnancy. • The conclusions regarding the associations between maternal antibiotics use during pregnancy and childhood ALL risk were inconsistent. What is New: • Maternal antibiotics consumption during pregnancy was not associated with the increased ALL risk in offspring. • Further laboratory evidences are needed to confirm the results.

Impact of antibiotics on the human microbiome and consequences for host health

It is well established that the gut microbiota plays an important role in host health and is perturbed by several factors including antibiotics. Antibiotic-induced changes in microbial composition can have a negative impact on host health including reduced microbial diversity, changes in functional attributes of the microbiota, formation, and selection of antibiotic-resistant strains making hosts more susceptible to infection with pathogens such as Clostridioides difficile. Antibiotic resistance is a global crisis and the increased use of antibiotics over time warrants investigation into its effects on microbiota and health. In this review, we discuss the adverse effects of antibiotics on the gut microbiota and thus host health, and suggest alternative approaches to antibiotic use.

Antibiotic treatments to mothers during the perinatal period leaving hidden trouble on infants

Antibiotic application during the perinatal period is unavoidable in the clinic, but the potential effects on mothers and infants remain unknown. Herein, 25 breast milk samples from mothers who received cefuroxime (CXM) or CXM + cefoxitin (CFX) treatments and fecal samples from their infants were collected to investigate the undesirable effects of antibiotics on the microbiota of mothers and neonates. Furthermore, five fecal samples of infants, whose mothers had antibiotic treatments, were collected at a 6-month postpartum follow-up visit to evaluate the long-term effects on infants' gut microbiota. Moreover, the relative abundance of antibiotic resistance genes (ARGs) in fecal samples was compared to investigate the transfer of ARGs in the infant gut microbiota. The results indicated that the antibiotic treatments had no influence on the microbiota of breast milk. The dominant bacterial phyla in the fecal samples changed to Firmicutes and Proteobacteria after antibiotic treatments, while the bacterial community showed a recuperative trend at the follow-up visits. In addition, the abundance of ARGs in the infant gut microbiota demonstrated a declining trend in the CXM- and CXM + CFX-treated groups, while ARG abundance presented a significant increasing trend after a 6-month recovery period.

CONCLUSION

Antibiotic treatments for mothers during the perinatal period disturb the gut microbiota in neonates. The infants' gut microbiota would partly return to their initial state after rehabilitation, but the transfer of ARGs would leave the hidden trouble of antibiotic resistance. Overall, the data presented here can help to guide the scientific use of antibiotics during the perinatal period and provide potential approaches to mitigate the negative consequences.

WHAT IS KNOWN

• Antibiotic application during the perinatal period is unavoidable in the clinic. • Misuse of antibiotics can cause various unintended consequences, especially for antibiotic resistance.

WHAT IS NEW

• Antibiotic treatments had no influence on the microbiota of breast milk but greatly disturbed the gut microbiota composition in infants. • The gut microbiota in infants would partly return to its initial state after rehabilitation but the transfer of ARGs would leave the hidden trouble of antibiotic resistance.

Intrauterine antibiotic exposure affected neonatal gut bacteria and infant growth speed

Although abundant evidence has suggested that early-life antibiotic exposure was associated with adipogenesis later in life, limited data were available on the effect of intrauterine antibiotic exposure on infant growth and growth speed. Additionally, few studies have investigated the role of the neonatal gut microbiota in the above association. In this study, we examined the association between intrauterine cumulative antibiotic exposure and infant growth and explored the potential role of the neonatal gut microbiota in the association. 295 mother-child pairs from the Shanghai Maternal-Child Pairs Cohort (MCPC) study were included, and meconium samples and infant growth measurements were assessed. Z-scores of length-for-age, weight-for-age (weight-for-age), and body mass index (BMI)-for-age (BMI-for-age) were calculated. Eighteen common antibiotics were measured in meconium. Multivariable linear regression models were applied to test the interrelationships between antibiotic exposure, diversity indicators, and the relative abundance of selected bacterial taxa from phylum to genus levels from least absolute shrinkage and selection operator (LASSO) and infant growth indicators. The detection rates of the 18 antibiotics, except for chlortetracycline, penicillin, and chloramphenicol, were below 10 %. Penicillin was found to be positively associated with infant growth at birth and with growth speed from 2 to 6 months. The Pielou and Simpson indexes were negatively associated with meconium penicillin. Nominally significant associations between penicillin and the relative abundances of several bacterial taxa from the phyla Proteobacteria, Bacteroidetes, and Firmicutes were found. The Pielou and Simpson indexes were also found to be negatively associated with infant growth. Among taxa selected from LASSO regression, the relative abundances of the phyla Actinobacteria and Firmicutes and order Bifidobacteriales were found to be significantly associated with weight and BMI growth speeds from 2 to 6 months. In conclusion, intrauterine antibiotic exposure can affect infant growth. The neonatal gut microbiota might play a role in the abovementioned association.

The neonatal microbiome in utero and beyond: perinatal influences and long-term impacts

The neonatal microbiome offers a valuable model for studying the origins of human health and disease. As the field of metagenomics expands, we also increase our understanding of early life influences on its development. In this review we will describe common techniques used to define and measure the microbiome. We will review in utero influences, normal perinatal development, and known risk factors for abnormal neonatal microbiome development. Finally, we will summarize current evidence that links early life microbial impacts on the development of chronic inflammatory diseases, obesity, and atopy.

Peripartum Antibiotics Exposure and the Risk of Autoimmune and Autism Disorders in the Offspring

Background As the use of antibiotics during the peripartum period increases, the incidence of autoimmune disorders and autism spectrum disorders (ASDs) is also increasing. In this study, we aim to assess if antibiotic exposure during the peripartum period affects the incidence of autoimmune diseases and ASD in the offspring. Methods We identified children (< 18 years of age) born in Olmsted County from January 1, 2003 through December 31, 2012. Offspring with celiac disease (CD), inflammatory bowel disease (IBD), or ASD diagnoses were matched to two controls on birth date, index date, mother's age at delivery, and sex. Data from the mother's medical records were retrieved to determine peripartum antibiotics use. Results A total of 242 cases and 484 matched controls were included in this study. Median age at the last follow-up was 11.3 years (range: 0.5-14.9), 73% were males in both groups. Odds of CD diagnosis was not statistically different between vaginal delivery with antibiotics compared with vaginal delivery with no antibiotics (odds ratio [OR] = 0.76, 95% confidence interval [CI]: 0.32-1.85), similarly in IBD (OR = 2.41, 95% CI: 0.53-10.98) and ASD (OR = 1.00, 95% CI:0.55-1.79). Preeclampsia or eclampsia was associated with offspring CD (OR = 3.20, 95% CI: 1.05-9.78). Smoking history and diabetes mellitus were associated with offspring ASD (OR = 1.84, 95% CI: 1.22-2.77 and OR = 2.01, 95% CI: 1.03-3.91, respectively). Conclusion In this cohort, we found no statistically significant association between peripartum antibiotics exposure and the development of CD, IBD, or ASD.

Antibiotic Intervention Affects Maternal Immunity During Gestation in Mice

Background

Pregnancy is a portentous stage in life, during which countless events are precisely orchestrated to ensure a healthy offspring. Maternal microbial communities are thought to have a profound impact on development. Although antibiotic drugs may interfere in these processes, they constitute the most frequently prescribed medication during pregnancy to prohibit detrimental consequences of infections. Gestational antibiotic intervention is linked to preeclampsia and negative effects on neonatal immunity. Even though perturbations in the immune system of the mother can affect reproductive health, the impact of microbial manipulation on maternal immunity is still unknown.

Aim

To assess whether antibiotic treatment influences maternal immunity during pregnancy.

Methods

Pregnant mice were treated with broad-spectrum antibiotics. The maternal gut microbiome was assessed. Numerous immune parameters throughout the maternal body, including placenta and amniotic fluid were investigated and a novel machine-learning ensemble strategy was used to identify immunological parameters that allow distinction between the control and antibiotic-treated group.

Results

Antibiotic treatment reduced diversity of maternal microbiota, but litter sizes remained unaffected. Effects of antibiotic treatment on immunity reached as far as the placenta. Four immunological features were identified by recursive feature selection to contribute to the most robust classification (splenic T helper 17 cells and CD5⁺ B cells, CD4⁺ T cells in mesenteric lymph nodes and RORγT mRNA expression in placenta).

Conclusion

In the present study, antibiotic treatment was able to affect the carefully coordinated immunity during pregnancy. These findings highlight the importance of inclusion of immunological parameters when studying the effects of medication used during gestation.

The Role of the Environment in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease clinicopathologically characterized by esophageal dysfunction. EoE is characterized by eosinophilic histologic inflammation indistinguishable from other atopic diseases such as asthma, eczema, or allergic rhinitis, which often co-occur in patients with EoE. This suggest a possible shared pathophysiology and triggers in the development of EoE with other atopic conditions. Although the evidence of EoE being linked to exposure to allergenic foods is strong, the connection between EoE and aeroallergens is less understood. In this review, we will discuss clinical, epidemiological, and animal studies that investigate how environmental allergens influence the clinical manifestations of EoE and its seasonality. It is also known that the developing immune system is significantly shaped by early-life exposures, pollution, climate change, and those factors that are known to influence development of asthma. We therefore also describe the evidence for and the gaps in our knowledge of the role of early-life exposures, pollution, and climate change in the development of EoE.

Exposure to antibiotics during pregnancy alters offspring outcomes

INTRODUCTION

The composition of microorganisms is closely related to human health. Antibiotic use during pregnancy may have adverse effects on the neonatal gut microbiome and subsequently affect infant health development, leading to childhood atopy and allergic diseases, intestinal, metabolic and brain disorders, and infection.

AREAS COVERED

This review includes the effect of maternal antibiotic use during pregnancy on potential diseases in animals and human offspring.

EXPERT OPINION

Exposure to antibiotics during pregnancy alters offspring outcomes. Alterations in the microbiome may potentially lower the risk of a range of problems and may also be a novel therapeutic target in children later in life.

Impacts of ceftriaxone exposure during pregnancy on maternal gut and placental microbiota and its influence on maternal and offspring immunity in mice

This study aimed to investigate the association between microbiota found in the maternal gut and placenta, and whether ceftriaxone exposure during pregnancy could alter these microbiota, and consequently affect the immunity of the mothers and their offspring. The microbiota in the feces and placenta of the dams were comprehensively analyzed using16S rRNA sequencing. Furthermore, viable bacteria in the placentas and blood of pups were also isolated by plate cultivation then taxonomically identified in detail by clone sequencing. Serum cytokines collected from dams and pups were quantitatively profiled using Luminex. The spleen organ index of dams was significantly lower and the offspring serum interleukin-6 levels were significantly higher in ceftriaxone-treated mice compared with the control group. The maternal fecal microbiota community was drastically altered in ceftriaxone-treated mice with significantly decreased diversity, depletion of Bacteroidetes and the blooming of Tenericutes. However, the placenta microbiota was dominated by Proteobacteria especially characteristically by Ralstonia, which was distinct from the maternal gut microbiota, regardless of whether ceftriaxone treatment or not. Viable bacteria have been found in placenta and blood cultures. These results indicated that ceftriaxone exposure in pregnancy could dramatically alter maternal intestinal microbiota, which affected the immunity of the mothers and their offspring at least partly, characteristically by enhanced pro-inflammatory responses. This study also indicated that the placenta might harbor its own microbes and the microbes were distinct from maternal gut microbiota, which may not be affected by oral administration of ceftriaxone during pregnancy.

Dose, Timing, and Spectrum of Prenatal Antibiotic Exposure and Risk of Childhood Asthma

BACKGROUND

The potential for prenatal antibiotic exposure to influence asthma risk is not clear. We aimed to determine the effect of timing, dose, and spectrum of prenatal antibiotic exposure on the risk of childhood asthma.

METHODS

We conducted a population-based cohort study of 84 214 mother-child dyads to examine the association of prenatal antibiotic exposure and childhood asthma using multivariable logistic regression models.

RESULTS

Sixty-four percent of pregnant women received antibiotics. Prenatal antibiotic exposure was associated dose-dependently with increased odds of childhood asthma (adjusted odds ratio [aOR] for interquartile increase of 2 courses [interquartile range, 0-2], 1.26 [95% confidence interval {CI}, 1.20-1.33]). Among children exposed to at least 1 course in utero, the effect of timing at the first course was moderated by total maternal courses. Among pregnant women receiving a single antibiotic course, timing of exposure had no effect on childhood asthma risk. Among women receiving > 1 course, early exposure of the first course was associated with greater childhood asthma risk. Compared to narrow spectrum-only antibiotic use, broad spectrum-only antibiotic exposure was associated with increased odds of asthma (aOR, 1.14 [95% CI, 1.05-1.24]). There were effect modifications (P < .001) by maternal asthma on total courses, and on timing of the first course, significant only among those without maternal asthma.

CONCLUSIONS

Increased cumulative dose, early pregnancy first course, and broad-spectrum antibiotic exposure were associated with childhood asthma risk. Our study provides important evidence supporting judicious prenatal antibiotic use, particularly timing of use and choice of antibiotics, in preventing subsequent childhood asthma.

Prenatal Immunity and Influences on Necrotizing Enterocolitis and Associated Neonatal Disorders

Prior to birth, the neonate has limited exposure to pathogens. The transition from the intra-uterine to the postnatal environment initiates a series of complex interactions between the newborn host and a variety of potential pathogens that persist over the first few weeks of life. This transition is particularly complex in the case of the premature and very low birth weight infant, who may be susceptible to many disorders as a result of an immature and underdeveloped immune system. Chief amongst these disorders is necrotizing enterocolitis (NEC), an acute inflammatory disorder that leads to necrosis of the intestine, and which can affect multiple systems and have the potential to result in long term effects if the infant is to survive. Here, we examine what is known about the interplay of the immune system with the maternal uterine environment, microbes, nutritional and other factors in the pathogenesis of neonatal pathologies such as NEC, while also taking into consideration the effects on the long-term health of affected children.

The crucial role of early-life gut microbiota in the development of type 1 diabetes

Early-life healthy gut microbiota has a profound implication on shaping the mucosal immune system as well as maintaining healthy status later in life, especially at the prenatal or neonatal stages, while intestinal dysbiosis in early life is associated with several autoimmune diseases, including type 1 diabetes (T1D). Since the gut microbiome is potentially modifiable, optimizing the intestinal bacterial composition in early life may be a novel option for T1D prevention. In this review, we will review current data depicting the crucial role of early-life intestinal microbiome in the development of T1D and discuss the possible mechanisms whereby early-life intestinal microbiome influences the T1D progression. We also summarize recent findings on environmental factors affecting gut microbiota colonization and interventions that may successfully alter microbial composition to discuss potential means of preventing T1D progression in at-risk children.

The Association between Early-Life Gut Microbiota and Long-Term Health and Diseases

Early life gut microbiota have been increasingly recognized as major contributors to short and/or long-term human health and diseases. Numerous studies have demonstrated that human gut microbial colonization begins at birth, but continues to develop a succession of taxonomic abundances for two to three years until the gut microbiota reaches adult-like diversity and proportions. Several factors, including gestational age (GA), delivery mode, birth weight, feeding types, antibiotic exposure, maternal microbiome, and diet, influence the diversity, abundance, and function of early life gut microbiota. Gut microbial life is essential for assisting with the digestion of food substances to release nutrients, exerting control over pathogens, stimulating or modulating the immune system, and influencing many systems such as the liver, brain, and endocrine system. Microbial metabolites play multiple roles in these interactions. Furthermore, studies provide evidence supporting that imbalances of the gut microbiota in early life, referred to as dysbiosis, are associated with specific childhood or adult disease outcomes, such as asthma, atopic dermatitis, diabetes, allergic diseases, obesity, cardiovascular diseases (CVD), and neurological disorders. These findings support that the human gut microbiota may play a fundamental role in the risk of acquiring diseases that may be programmed during early life. In fact, it is critical to explore the role of the human gut microbiota in early life.

Prenatal antibiotic exposure and risk of attention-deficit/hyperactivity disorder: a population-based cohort study

BACKGROUND

Abnormal microbiota composition induced by prenatal exposure to antibiotics has been proposed as a potential contributor to the development of attention-deficit/hyperactivity disorder (ADHD). We examined the association between prenatal antibiotic exposure and risk of ADHD.

METHODS

We conducted a population-based retrospective cohort study of children born in Manitoba, Canada, between 1998 and 2017 and their mothers. We defined exposure as the mother having filled 1 or more antibiotic prescriptions during pregnancy. The outcome was diagnosis of ADHD in the offspring, as identified in administrative databases. We estimated hazard ratios (HRs) using Cox proportional hazards regression in the overall cohort, in a separate cohort matched on high-dimensional propensity scores and in a sibling cohort.

RESULTS

In the overall cohort, consisting of 187 605 children, prenatal antibiotic dispensation was associated with increased risk of ADHD (HR 1.22, 95% confidence interval [CI] 1.18-1.26). Similar results were observed in the matched cohort of 129 674 children (HR 1.20, 95% CI 1.15-1.24) but not in the sibling cohort (HR 1.06, 95% CI 0.99-1.13). Two negative-control analyses indicated a positive association with ADHD despite the lack of a reasonable biological mechanism, which suggested that the observed association between prenatal antibiotic dispensation and risk of ADHD was likely due to confounding.

INTERPRETATION

In our study, prenatal antibiotic exposure was not associated with increased risk of ADHD in children. Although the risk was higher in the overall and matched cohorts, it was likely overestimated because of unmeasured confounding. Future studies are warranted to examine other factors affecting microbiota composition in association with risk of ADHD.

Dietary SCFAs Immunotherapy: Reshaping the Gut Microbiota in Diabetes

Diet-microbiota related inflammatory conditions such as obesity, autoimmune type 1 diabetes (T1D), type 2 diabetes (T2D), cardiovascular disease (CVD) and gut infections have become a stigma in Western societies and developing nations. This book chapter examines the most relevant pre-clinical and clinical studies about diet-gut microbiota approaches as an alternative therapy for diabetes. We also discuss what we and others have extensively investigated- the power of dietary short-chain fatty acids (SCFAs) technology that naturally targets the gut microbiota as an alternative method to prevent and treat diabetes and its related complications.

Impact of Intrapartum Antibiotic Prophylaxis on Offspring Microbiota

Infants are born into a world filled with microbes and must adapt without undue immune response while exploiting the microbiota's ability to produce otherwise unavailable nutrients. The process by which humans and microbes establish this relationship has only recently begun to be studied with the aid of genomic methods. Nearly half of all pregnant women receive antibiotics during gestation to prevent maternal and neonatal infection. Though this has been largely successful in reducing early-onset sepsis, we have yet to understand the long-term consequences of antibiotic administration during gestation to developing infants. Studies involving antibiotic use in infants suggest that dysbiosis during this period is associated with increased obesity, allergy, autoimmunity, and chronic diseases in adulthood, however, research around the limited doses of intravenous antibiotics used for intrapartum prophylaxis is limited. In this mini review, we focused on the state of the science regarding the effects of intrapartum antibiotic prophylaxis on the newborn microbial colonization process. Although, the literature indicates that there is wide variety in the specific bacteria that colonize infants from birth, limited parenteral antibiotic administration prior to delivery consistently affects the microbiota of infants by decreasing bacteria in the phylum Bacteroidetes and increasing bacteria in the phylum Proteobacteria, thus altering the normal pattern of colonization that infants experience. Delivery by cesarean section and formula feeding magnify and prolong this effect. Our mini review shows that the impact of intravenous antibiotic administration during gestation has on early colonization, growth, or immune programming in the developing offspring has not been well studied in human or animal models.

Maternal exposures and the infant gut microbiome: a systematic review with meta-analysis

Early life, including the establishment of the intestinal microbiome, represents a critical window of growth and development. Postnatal factors affecting the microbiome, including mode of delivery, feeding type, and antibiotic exposure have been widely investigated, but questions remain regarding the influence of exposures in utero on infant gut microbiome assembly. This systematic review aimed to synthesize evidence on exposures before birth, which affect the early intestinal microbiome. Five databases were searched in August 2019 for studies exploring pre-pregnancy or pregnancy 'exposure' data in relation to the infant microbiome. Of 1,441 publications identified, 76 were included. Factors reported influencing microbiome composition and diversity included maternal antibiotic and probiotic uses, dietary intake, pre-pregnancy body mass index (BMI), gestational weight gain (GWG), diabetes, mood, and others. Eleven studies contributed to three meta-analyses quantifying associations between maternal intrapartum antibiotic exposure (IAP), BMI and GWG, and infant microbiome alpha diversity (Shannon Index). IAP, maternal overweight/obesity and excessive GWG were all associated with reduced diversity. Most studies were observational, few included early recruitment or longitudinal follow-up, and the timing, frequency, and methodologies related to stool sampling and analysis were variable. Standardization and collaboration are imperative to enhance understanding in this complex and rapidly evolving area.

100 years post-insulin: immunotherapy as the next frontier in type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease characterised by T cell-mediated destruction of the insulin-producing β cells in the pancreas. Similar to other autoimmune diseases, the incidence of T1D is increasing globally. The discovery of insulin 100 years ago dramatically changed the outlook for people with T1D, preventing this from being a fatal condition. As we celebrate the centenary of this milestone, therapeutic options for T1D are once more at a turning point. Years of effort directed at developing immunotherapies are finally starting to pay off, with signs of progress in new onset and even preventative settings. Here, we review a selection of immunotherapies that have shown promise in preserving β cell function and highlight future considerations for immunotherapy in the T1D setting.

Vertical transmission of gut microbiota: Points of action of environmental factors influencing brain development

Environmental factors in early life interact with genetics to exert a long-lasting and broad influence on health and disease. There has been a marked growth in the number of environmental factors studied in association with neurodevelopmental disorders. Colonization of the gut microbiota in the offspring uses the maternal resident flora as a primary source of bacteria during perinatal periods. Several lines of evidence have shown that various environmental factors including the mode of delivery, exposure to antibiotics, infection, stress, diet, quality of breast milk, and type of infant-feeding during the perinatal periods can perturb the gut microbiota colonization in the offspring, finally leading to disturbances in brain development. This study proposes that the gut microbiota seeded primarily by maternal microbiota, and the postnatal colonization of the microbiota in the offspring can be critical action points of environmental factors when deciphering the mechanisms of actions of environmental factors in brain development. This research reviews the inheritance and colonization of the microbiota during early life and the potential actions of the environmental factors influencing brain development in the offspring by modulating the vertical transmission of gut microbiota.

The early life education of the immune system: Moms, microbes and (missed) opportunities

The early life immune system is characterized by unique developmental milestones. Functionally diverse immune cells arise from distinct waves of hematopoietic stem cells, a phenomenon referred to as 'layered' immunity. This stratified development of immune cells extends to lineages of both innate and adaptive cells. The defined time window for the development of these immune cells lends itself to the influence of specific exposures typical of the early life period. The perinatal immune system develops in a relatively sterile fetal environment but emerges into one filled with a multitude of antigenic encounters. A major burden of this comes in the form of the microbiota that is being newly established at mucosal surfaces of the newborn. Accumulating evidence suggests that early life microbial exposures, including those arising in utero, can imprint long-lasting changes in the offspring's immune system and determine disease risk throughout life. In this review, I highlight unique features of early life immunity and explore the role of intestinal bacteria in educating the developing immune system.

The Role of the Gut Microbiota in Dietary Interventions for Depression and Anxiety

There is emerging evidence that an unhealthy dietary pattern may increase the risk of developing depression or anxiety, whereas a healthy dietary pattern may decrease it. This nascent research suggests that dietary interventions could help prevent, or be an alternative or adjunct therapy for, depression and anxiety. The relation, however, is complex, affected by many confounding variables, and is also likely to be bidirectional, with dietary choices being affected by stress and depression. This complexity is reflected in the data, with sometimes conflicting results among studies. As the research evolves, all characteristics of the relation need to be considered to ensure that we obtain a full understanding, which can potentially be translated into clinical practice. A parallel and fast-growing body of research shows that the gut microbiota is linked with the brain in a bidirectional relation, commonly termed the microbiome-gut-brain axis. Preclinical evidence suggests that this axis plays a key role in the regulation of brain function and behavior. In this review we discuss possible reasons for the conflicting results in diet-mood research, and present examples of areas of the diet-mood relation in which the gut microbiota is likely to be involved, potentially explaining some of the conflicting results from diet and depression studies. We argue that because diet is one of the most significant factors that affects human gut microbiota structure and function, nutritional intervention studies need to consider the gut microbiota as an essential piece of the puzzle.

Microbiota derived factors as drivers of type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease caused by complex interactions between host genetics and environmental factors, culminating in the T-cell mediated destruction of the insulin producing cells in the pancreas. The rapid increase in disease frequency over the past 50 years or more has been too rapid to attribute to genetics. Dysbiosis of the gut microbiota is currently being widely investigated as a major contributor to environmental change driving increased T1D onset. In this chapter, we discuss the major changes in gut microbiota composition and function linked to T1D risk as well as the potential origin of these changes including infant diet, antibiotic use and host genetics. We examine the interaction between inflammation and gut barrier function and the dysbiotic gut microbiota that have been linked to T1D.

Early-Life Gut Microbiome-The Importance of Maternal and Infant Factors in Its Establishment

The early-life microbiome is gaining appreciation as a major influencer in human development and long-term health. Multiple factors are known to influence the initial colonization, development, and function of the neonatal gut microbiome. In addition, alterations in early-life gut microbial composition is associated with several chronic health conditions such as obesity, asthma, and allergies. In this review, we focus on both maternal and infant factors known to influence early-life gut colonization. Also reviewed is the important role of infant feeding, including evidence-based strategies for maternal and infant supplementation with the goal to protect and/or restore the infant gut microbiome.

Exposure to Amoxicillin in Early Life Is Associated With Changes in Gut Microbiota and Reduction in Blood Pressure: Findings From a Study on Rat Dams and Offspring

Background

Pediatric hypertension is recognized as an emerging global health concern. Although new guidelines are developed for facilitating clinical management, the reasons for the prevalence of hypertension in children remain unknown. Genetics and environmental factors do not fully account for the growing incidence of pediatric hypertension. Because stable bacterial flora in early life are linked with health outcomes later in life, we hypothesized that reshaping of gut microbiota in early life affects blood pressure (BP) of pediatric subjects.

Methods and Results

To test this hypothesis, we administered amoxicillin, the most commonly prescribed pediatric antibiotic, to alter gut microbiota of young, genetically hypertensive rats (study 1) and dams during gestation and lactation (study 2) and recorded their BP. Reshaping of microbiota with reductions in Firmicutes/Bacteriodetes ratio were observed. Amoxicillin treated rats had lower BP compared with untreated rats. In young rats treated with amoxicillin, the lowering effect on BP persisted even after antibiotics were discontinued. Similarly, offspring from dams treated with amoxicillin showed lower systolic BP compared with control rats. Remarkably, in all cases, a decrease in BP was associated with lowering of Veillonellaceae, which are succinate‐producing bacteria. Elevated plasma succinate is reported in hypertension. Accordingly, serum succinate was measured and found lower in animals treated with amoxicillin.

Conclusions

Our results demonstrate a direct correlation between succinate‐producing gut microbiota and early development of hypertension and indicate that reshaping gut microbiota, especially by depleting succinate‐producing microbiota early in life, may have long‐term benefits for hypertension‐prone individuals.

Early Life Risk Factors in Pediatric EoE: Could We Prevent This Modern Disease?

Eosinophilic esophagitis (EoE) is a chronic antigen-mediated inflammatory disease that affects the esophagus. In the last 20 years, a large number of epidemiological studies showed a significant increase in the incidence and prevalence of EoE, especially in developed countries. This phenomenon might correlate to the overall increase in pediatric allergic diseases or might be a result of improved medical awareness and knowledge through modern diagnostic instruments. Since 1993, when EoE was first recognized as a distinct clinical entity, several signs of progress in the pathophysiology of EoE were achieved. However, a few studies reported data on early risk factors for pediatric EoE and how these factors may interfere with genes. Currently, the most defined risk factors for EoE are male sex, Caucasian race, and atopic comorbidities. Other putative risk factors may include alterations in epithelial barrier function and fibrous remodeling, esophageal dysbiosis, variation in the nature and timing of oral antigen exposure, and early prescription of proton pump inhibitors and antibiotics. Notably, the timing and nature of food antigen exposure may be fundamental in inducing or reversing immune tolerance, but no studies are reported. This review summarized the current evidence on the risk factors that might contribute to the increasing development of EoE, focusing on the possible preventive role of early interventions.

Influence of maternal microbiota during pregnancy on infant immunity

Microbiota from various maternal sites, including the gut, vagina and breast milk, are known to influence colonization in infants. However, emerging evidence suggests that these sites may exert their influence prior to delivery, in turn influencing fetal immune development. The dogma of a sterile womb continues to be challenged. Regardless, there is convincing evidence that the composition of the maternal gut prior to delivery influences neonatal immunity. Therefore, while the presence and function of placental microbiome is not clear, there is consensus that the gut microbiota during pregnancy is a critical determinant of offspring health. Data supporting the notion of bacterial translocation from the maternal gut to extra-intestinal sites during pregnancy are emerging, and potentially explain the presence of bacteria in breast milk. Much evidence suggests that the maternal gut microbiota during pregnancy potentially determines the development of atopy and autoimmune phenotypes in offspring. Here, we highlight the role of the maternal microbiota prior to delivery on infant immunity and predisposition to diseases. Moreover, we discuss potential mechanisms that underlie this phenomenon.

Prenatal antibiotics exposure and the risk of autism spectrum disorders: A population-based cohort study

Background

Prenatal antibiotic exposure induces changes in infants’ gut microbiota composition and is suggested as a possible contributor in the development of autism spectrum disorders (ASD). In this study, we examined the association between prenatal antibiotic exposure and the risk of ASD.

Methods

This was a population-based cohort study utilizing the Manitoba Population Research Data Repository. The cohort included 214 834 children born in Manitoba, Canada between April 1, 1998 and March 31, 2016. Exposure was defined as having filled one or more antibiotic prescription during pregnancy. The outcome was autism spectrum disorder diagnosis. Multivariable Cox proportional hazards regression was used to estimate the risk of developing ASD in the overall cohort and in a sibling cohort.

Results

Of all subjects, 80 750 (37.6%) were exposed to antibiotics prenatally. During follow-up, 2965 children received an ASD diagnosis. Compared to children who were not exposed to antibiotics prenatally, those who were exposed had a higher risk of ASD: (adjusted HR 1.10 [95% CI 1.01, 1.19]). The association was observed in those exposed to antibiotics in the second or third trimester (HR 1.11 [95% CI 1.01, 1.23] and 1.17 [95% CI 1.06, 1.30], respectively). In the siblings’ cohort, ASD risk estimate remained unchanged (adjusted HR 1.08 [95% CI 0.90, 1.30], although it was not statistically significant.

Conclusions

Prenatal antibiotic exposure is associated with a small increase in the risk of ASD. Given the potential of residual confounding beyond what it was controlled through our study design and because of possible confounding by indication, such a small risk increase in the population is not expected to be clinically significant.

Altered Gut Microbiota Activate and Expand Insulin B15-23-Reactive CD8+ T Cells

Insulin is a major autoantigen in type 1 diabetes, targeted by both CD8 and CD4 T cells. We studied an insulin-reactive T-cell receptor (TCR) α-chain transgenic NOD mouse on a TCRCα and proinsulin 2 (PI2)-deficient background, designated as A22Cα^-/-PI2^-/- NOD mice. These mice develop a low incidence of autoimmune diabetes. To test the role of gut microbiota on diabetes development in this model system, we treated the A22Cα^-/-PI2^-/- NOD mice with enrofloxacin, a broad-spectrum antibiotic. The treatment led to male mice developing accelerated diabetes. We found that enrofloxacin increased the frequency of the insulin-reactive CD8+ T cells and activated the cells in the Peyer's patches and pancreatic lymph nodes, together with induction of immunological effects on the antigen-presenting cell populations. The composition of gut microbiota differed between the enrofloxacin-treated and untreated mice and also between the enrofloxacin-treated mice that developed diabetes compared with those that remained normoglycemic. Our results provide evidence that the composition of the gut microbiota is important for determining the expansion and activation of insulin-reactive CD8+ T cells.

Neonatal microbiome - a brief review

The long-held concept of fetus being nurtured in a sterile environment has been challenged by many recent studies that have identified bacterial communities in meconium, amniotic fluid and the placenta concluding that the microbial colonization of fetal gut begins in utero and continues during the first 2 years of life. This microbial colonization of newborn's gut during prenatal, intrapartum, and postnatal period depends on multiple factors, e.g. maternal diet, stress, antibiotic exposure, mode of delivery, type of feeding (human milk versus formula), etc., and imparts a critical role in the development of gastrointestinal, immunological, and neural systems in newborns. This article briefly reviews the current state of knowledge of microbiome in the maternal fetal unit and its impact on subsequent neonatal health and diseases.

Microbe-metabolite-host axis, two-way action in the pathogenesis and treatment of human autoimmunity

The role of microorganism in human diseases cannot be ignored. These microorganisms have evolved together with humans and worked together with body's mechanism to maintain immune and metabolic function. Emerging evidence shows that gut microbe and their metabolites open up new doors for the study of human response mechanism. The complexity and interdependence of these microbe-metabolite-host interactions are rapidly being elucidated. There are various changes of microbial levels in models or in patients of various autoimmune diseases (AIDs). In addition, the relevant metabolites involved in mechanism mainly include short-chain fatty acids (SCFAs), bile acids (BAs), and polysaccharide A (PSA). Meanwhile, the interaction between microbes and host genes is also a factor that must be considered. It has been demonstrated that human microbes are involved in the development of a variety of AIDs, including organ-specific AIDs and systemic AIDs. At the same time, microbes or related products can be used to remodel body's response to alleviate or cure diseases. This review summarizes the latest research of microbes and their related metabolites in AIDs. More importantly, it highlights novel and potential therapeutics, including fecal microbial transplantation, probiotics, prebiotics, and synbiotics. Nonetheless, exact mechanisms still remain elusive, and future research will focus on finding a specific strain that can act as a biomarker of an autoimmune disease.

Perinatal Interactions between the Microbiome, Immunity, and Neurodevelopment

The microbiome modulates host immune function across the gastrointestinal tract, peripheral lymphoid organs, and central nervous system. In this review, we highlight emerging evidence that microbial effects on select immune phenotypes arise developmentally, where the maternal and neonatal microbiome influence immune cell ontogeny in the offspring during gestation and early postnatal life. We further discuss roles for the perinatal microbiome and early-life immunity in regulating normal neurodevelopmental processes. In addition, we examine evidence that abnormalities in microbiota-neuroimmune interactions during early life are associated with altered risk of neurological disorders in humans. Finally, we conclude by evaluating the potential implications of microbiota-immune interventions for neurological conditions. Continued progress toward dissecting mechanistic interactions between the perinatal microbiota, immune system, and nervous system might uncover fundamental insights into how developmental interactions across physiological systems inform later-life health and disease.