Factors Influencing the Intestinal Microbiome During the First Year of Life

Human Milk Microbiome-A Review of Scientific Reports

One of the most important bioactive components of breast milk are free breast milk oligosaccharides, which are a source of energy for commensal intestinal microorganisms, stimulating the growth of Bifidobacterium, Lactobacillus, and Bacteroides in a child's digestive tract. There is some evidence that maternal, perinatal, and environmental-cultural factors influence the modulation of the breast milk microbiome. This review summarizes research that has examined the composition of the breast milk microbiome and the factors that may influence it. The manuscript highlights the potential importance of the breast milk microbiome for the future development and health of children. The origin of bacteria in breast milk is thought to include the mother's digestive tract (entero-mammary tract), bacterial exposure to the breast during breastfeeding, and the retrograde flow of breast milk from the infant's mouth to the woman's milk ducts. Unfortunately, despite increasingly more precise methods for assessing microorganisms in human milk, the topic of the human milk microbiome is still quite limited and requires scientific research that takes into account various conditions.

Could the gut microbiota be capable of making individuals more or less susceptible to environmental toxicants?

Environmental toxicants are chemical substances capable to impair environmental quality and exert adverse effects on humans and other animals. The main routes of exposure to these pollutants are through the respiratory tract, skin, and oral ingestion. When ingested orally, they will encounter trillions of microorganisms that live in a community - the gut microbiota (GM). While pollutants can disrupt the GM balance, GM plays an essential role in the metabolism and bioavailability of these chemical compounds. Under physiological conditions, strategies used by the GM for metabolism and/or excretion of xenobiotics include reductive and hydrolytic transformations, lyase and functional group transfer reactions, and enzyme-mediated functional transformations. Simultaneously, the host performs metabolic processes based mainly on conjugation, oxidation, and hydrolysis reactions. Thus, due to the broad variety of bacterial enzymes present in GM, the repertoire of microbial transformations of chemicals is considered a key component of the machinery involved in the metabolism of pollutants in humans and other mammals. Among pollutants, metals deserve special attention once contamination by metals is a worldwide problem, and their adverse effects can be observed even at very low concentrations due to their toxic properties. In this review, bidirectional interaction between lead, arsenic, cadmium, and mercury and the host organism and its GM will be discussed given the most recent literature, presenting an analysis of the ability of GM to alter the host organism's susceptibility to the toxic effects of heavy metals, as well as evaluating the extent to which interventions targeting the microbiota could be potential initiatives to mitigate the adverse effects resulting from poisoning by heavy metals. This study is the first to highlight the overlap between some of the bacteria found to be altered by metal exposure and the bacteria that also aid the host organism in the metabolism of these metals. This could be a key factor to determine the beneficial species able to minimize the toxicity of metals in future therapeutic approaches.

Factors Influencing Neonatal Gut Microbiome and Health with a Focus on Necrotizing Enterocolitis

Maturational changes in the gut start in utero and rapidly progress after birth, with some functions becoming fully developed several months or years post birth including the acquisition of a full gut microbiome, which is made up of trillions of bacteria of thousands of species. Many factors influence the normal development of the neonatal and infantile microbiome, resulting in dysbiosis, which is associated with various interventions used for neonatal morbidities and survival. Extremely low gestational age neonates (<28 weeks' gestation) frequently experience recurring arterial oxygen desaturations, or apneas, during the first few weeks of life. Apnea, or the cessation of breathing lasting 15-20 s or more, occurs due to immature respiratory control and is commonly associated with intermittent hypoxia (IH). Chronic IH induces oxygen radical diseases of the neonate, including necrotizing enterocolitis (NEC), the most common and devastating gastrointestinal disease in preterm infants. NEC is associated with an immature intestinal structure and function and involves dysbiosis of the gut microbiome, inflammation, and necrosis of the intestinal mucosal layer. This review describes the factors that influence the neonatal gut microbiome and dysbiosis, which predispose preterm infants to NEC. Current and future management and therapies, including the avoidance of dysbiosis, the use of a human milk diet, probiotics, prebiotics, synbiotics, restricted antibiotics, and fecal transplantation, for the prevention of NEC and the promotion of a healthy gut microbiome are also reviewed. Interventions directed at boosting endogenous and/or exogenous antioxidant supplementation may not only help with prevention, but may also lessen the severity or shorten the course of the disease.

Microbial and immune faecal determinants in infants hospitalized with COVID-19 reflect bifidobacterial dysbiosis and immature intestinal immunity

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread rapidly worldwide, seriously endangering human health. Although SARS-CoV-2 had a lower impact on paediatric population, children with COVID-19 have been reported as suffering from gastrointestinal (GI) symptoms at a higher rate than adults. The aim of this work was to evaluate faeces as a source of potential biomarkers of severity in the paediatric population, with an emphasis on intestinal microbiota and faecal immune mediators, trying to identify possible dysbiosis and immune intestinal dysfunction associated with the risk of hospitalization. This study involved 19 patients with COVID-19 under 24 months of age hospitalized during the pandemic at 6 different hospitals in Spain, and it included a comparable age-matched healthy control group (n = 18). Patients and controls were stratified according to their age in two groups: newborns or young infants (from 0 to 3 months old) and toddlers (infants from 6 to 24 months old). To characterize microbial intestinal communities, sequencing with Illumina technology of total 16S rDNA amplicons and internal transcribed spacer (ITS) amplicons of bifidobacteria were used. Faecal calprotectin (FC) and a range of human cytokines, chemokines, and growth factors were measured in faecal samples using ELISA and a multiplex system. Significant reduction in the abundance of sequences belonging to the phylum Actinobacteria was found in those infants with COVID-19, as well as in the Bifidobacteriaceae family. A different pattern of bifidobacteria was observed in patients, mainly represented by lower percentages of Bifidobacterium breve, as compared with controls. In the group of hospitalized young infants, FC was almost absent compared to age-matched healthy controls. A lower prevalence in faecal excretion of immune factors in these infected patients was also observed.

CONCLUSION

 Hospitalized infants with COVID-19 were depleted in some gut bacteria, such as bifidobacteria, in particular Bifidobacterium breve, which is crucial for the proper establishment of a functional intestinal microbiota, and important for the development of a competent immune system. Our results point to a possible immature immune system at intestine level in young infants infected by SARS-CoV2 requiring hospitalization.

WHAT IS KNOWN

• Although SARS-CoV-2 had a lower impact on paediatric population, children with COVID-19 have been reported as suffering from gastrointestinal symptoms at a higher rate than adults. • Changes in microbial composition have been described in COVID-19 adult patients, although studies in children are limited.

WHAT IS NEW

• The first evidence that hospitalized infants with COVID-19 during the pandemic had a depletion in bifidobacteria, particularly in Bifidobacterium breve, beneficial gut bacteria in infancy that are crucial for the proper establishment of a competent immune system. • In young infants (under 3 months of age) hospitalized with SARS-CoV2 infection, the aberrant bifidobacterial profile appears to overlap with a poor intestinal immune development as seen by calprotectin and the trend of immunological factors excreted in faeces.

An Extensively Hydrolyzed Formula Supplemented with Two Human Milk Oligosaccharides Modifies the Fecal Microbiome and Metabolome in Infants with Cow's Milk Protein Allergy

Cow's milk protein allergy (CMPA) is a prevalent food allergy among infants and young children. We conducted a randomized, multicenter intervention study involving 194 non-breastfed infants with CMPA until 12 months of age (clinical trial registration: NCT03085134). One exploratory objective was to assess the effects of a whey-based extensively hydrolyzed formula (EHF) supplemented with 2'-fucosyllactose (2'-FL) and lacto-N-neotetraose (LNnT) on the fecal microbiome and metabolome in this population. Thus, fecal samples were collected at baseline, 1 and 3 months from enrollment, as well as at 12 months of age. Human milk oligosaccharides (HMO) supplementation led to the enrichment of bifidobacteria in the gut microbiome and delayed the shift of the microbiome composition toward an adult-like pattern. We identified specific HMO-mediated changes in fecal amino acid degradation and bile acid conjugation, particularly in infants commencing the HMO-supplemented formula before the age of three months. Thus, HMO supplementation partially corrected the dysbiosis commonly observed in infants with CMPA. Further investigation is necessary to determine the clinical significance of these findings in terms of a reduced incidence of respiratory infections and other potential health benefits.

Metagenomics analysis of the neonatal intestinal resistome

Introduction

The intestinal microbiome forms a major reservoir for antibiotic resistance genes (ARGs). Little is known about the neonatal intestinal resistome.

Objective

The objective of this study was to investigate the intestinal resistome and factors that influence the abundance of ARGs in a large cohort of neonates.

Methods

Shotgun metagenomics was used to analyse the resistome in stool samples collected at 1 week of age from 390 healthy, term-born neonates who did not receive antibiotics.

Results

Overall, 913 ARGs belonging to 27 classes were identified. The most abundant ARGs were those conferring resistance to tetracyclines, quaternary ammonium compounds, and macrolide-lincosamide-streptogramin-B. Phylogenetic composition was strongly associated with the resistome composition. Other factors that were associated with the abundance of ARGs were delivery mode, gestational age, birth weight, feeding method, and antibiotics in the last trimester of pregnancy. Sex, ethnicity, probiotic use during pregnancy, and intrapartum antibiotics had little effect on the abundance of ARGs.

Conclusion

Even in the absence of direct antibiotic exposure, the neonatal intestine harbours a high abundance and a variety of ARGs.

Lactic acid bacteria-derived exopolysaccharide: Formation, immunomodulatory ability, health effects, and structure-function relationship

Exopolysaccharides (EPSs) synthesized by lactic acid bacteria (LAB) have implications for host health and act as food ingredients. Due to the variability of LAB-EPS (lactic acid bacteria-derived exopolysaccharide) gene clusters, especially the glycosyltransferase genes that determine monosaccharide composition, the structure of EPS is very rich. EPSs are synthesized by LAB through the extracellular synthesis pathway and the Wzx/Wzy-dependent pathway. LAB-EPS has a strong immunomodulatory ability. The EPSs produced by different genera of LAB, especially Lactobacillus, Leuconostoc, and Streptococcus, have different immunomodulatory abilities because of their specific structures. LAB-EPS possesses other health effects, including antitumor, antioxidant, intestinal barrier repair, antimicrobial, antiviral, and cholesterol-lowering activities. The bioactivities of LAB-EPS are tightly related to their structures such us monosaccharide composition, glycosidic bonds, and molecular weight (MW). For the excellent physicochemical property, LAB-EPS acts as product improvers in dairy, bakery food, and meat in terms of stability, emulsification, thickening, and gelling. We systematically summarize the detailed process of EPS from synthesis to application, with emphasis on physiological mechanisms of EPS, and specific structure-function relationship, which provides theoretical support for the potential commercial value in the pharmaceutical, chemical, food, and cosmetic industries.

Assessment of glucocorticoid and antibiotic exposure as risk factors for diabetes mellitus in selected dog breeds attending UK primary-care clinics

BACKGROUND

Diabetes mellitus (DM) is an important endocrine disorder in dogs. This study explored prior exposure to glucocorticoids or antibiotic treatment as risk factors for developing DM in dogs attending primary-care VetCompass clinics in the UK.

METHODS

A breed frequency matched case-control study nested in a cohort of dogs (n = 480,469) aged 3 years or over was used to explore associations between glucocorticoid and antibiotic exposure and the odds of developing DM.

RESULTS

A total of 565 cases and 2179 controls were included. Dogs with DM had over four times the odds of exposure to glucocorticoids within 6 weeks prior to diagnosis (odds ratio [OR] 4.07, 95% confidence interval [CI] 2.41-6.89, p < 0.001) compared to controls within 6 weeks prior to a randomly selected quasi-date of diagnosis. Dogs that had only one unique documented antibiotic course had a decreased odds of developing DM (OR 0.65, 95% CI 0.46-0.91, p = 0.012) compared to dogs that had no documented courses of antibiotics.

LIMITATIONS

This study only included selected breeds, so the results may not be generalisable to all dog breeds.

CONCLUSIONS

Exposure to glucocorticoids is associated with a substantial increase in the risk of developing DM for the dog breeds included in this analysis.

Gastrointestinal, vaginal, nasopharyngeal, and breast milk microbiota profiles and breast milk metabolomic changes in Gambian infants over the first two months of lactation: A prospective cohort study

Microbiota composition in breast milk affects intestinal and respiratory microbiota colonization and the mucosal immune system's development in infants. The metabolomic content of breast milk is thought to interact with the microbiota and may influence developing infant immunity. One hundred seven Gambian mothers and their healthy, vaginally delivered, exclusively breastfed infants were included in our study. We analyzed 32 breast milk samples, 51 maternal rectovaginal swabs and 30 infants' rectal swabs at birth. We also analyzed 9 breast milk samples and 18 infants' nasopharyngeal swabs 60 days post-delivery. We used 16S rRNA gene sequencing to determine the microbiota composition. Metabolomic profiling analysis was performed on colostrum and mature breast milk samples using a multiplatform approach combining 1-H Nuclear Magnetic Resonance Spectroscopy and Gas Chromatography-Mass Spectrometry. Bacterial communities were distinct in composition and diversity across different sample types. Breast milk composition changed over the first 60 days of lactation. α-1,4- and α-1,3-fucosylated human milk oligosaccharides, and other 33 key metabolites in breast milk (monosaccharides, sugar alcohols and fatty acids) increased between birth and day 60 of life. This study's results indicate that infant gut and respiratory microbiota are unique bacterial communities, distinct from maternal gut and breast milk, respectively. Breast milk microbiota composition and metabolomic profile change throughout lactation. These changes may contribute to the infant's immunological, metabolic, and neurological development and could consist the basis for future interventions to correct disrupted early life microbial colonization.

The association between early-life gut microbiota and childhood respiratory diseases: a systematic review

Data from animal models suggest a role of early-life gut microbiota in lung immune development, and in establishing susceptibility to respiratory infections and asthma in humans. This systematic review summarises the association between infant (ages 0-12 months) gut microbiota composition measured by genomic sequencing, and childhood (ages 0-18 years) respiratory diseases (ie, respiratory infections, wheezing, or asthma). Overall, there was evidence that low α-diversity and relative abundance of particular gut-commensal bacteria genera (Bifidobacterium, Faecalibacterium, Ruminococcus, and Roseburia) are associated with childhood respiratory diseases. However, results were inconsistent and studies had important limitations, including insufficient characterisation of bacterial taxa to species level, heterogeneous outcome definitions, residual confounding, and small sample sizes. Large longitudinal studies with stool sampling during the first month of life and shotgun metagenomic approaches to improve bacterial and fungal taxa resolution are needed. Standardising follow-up times and respiratory disease definitions and optimising causal statistical approaches might identify targets for primary prevention of childhood respiratory diseases.

Evolution of the Gut Microbiome in HIV-Exposed Uninfected and Unexposed Infants during the First Year of Life

HIV-exposed uninfected infants (HEU) have abnormal immunologic functions and increased infectious morbidity in the first 6 months of life, which gradually decreases thereafter. The mechanisms underlying HEU immune dysfunctions are unknown. We hypothesized that unique characteristics of the HEU gut microbiota associated with maternal HIV status may underlie the HEU immunologic dysfunctions. We characterized the infant gut, maternal gut, and breast milk microbiomes of mother-infant pairs, including 123 with HEU and 117 with HIV-uninfected infants (HUU), from South Africa. Pan-bacterial 16S rRNA gene sequencing was performed on (i) infant stool at 6, 28, and 62 weeks; (ii) maternal stool at delivery and 62 weeks; and (iii) breast milk at 6 weeks. Infant gut alpha and beta diversities were similar between groups. Microbial composition significantly differed, including 12 genera, 5 families and 1 phylum at 6 weeks; 12 genera and 2 families at 28 weeks; and 2 genera and 2 families at 62 weeks of life. Maternal gut microbiomes significantly differed in beta diversity and microbial composition, and breast milk microbiomes differed in microbial composition only. Infant gut microbiotas extensively overlapped with maternal gut and minimally with breast milk microbiotas. Nevertheless, exclusively breastfed HEU and HUU had less divergent microbiomes than nonexclusively breastfed infants. Feeding pattern and maternal gut microbiome imprint the HEU gut microbiome. Compared to HUU, the HEU gut microbiome prominently differs in early infancy, including increased abundance of taxa previously observed to be present in excess in adults with HIV. The HEU and HUU gut microbiome compositions converge over time, mirroring the kinetics of HEU infectious morbidity risk.

Persistent Symptoms After Treatment of Lyme Disease

Most patients with Lyme disease will fully recover with recommended antibiotic therapy. However, some patients report persisting nonspecific symptoms after treatment, referred to as posttreatment Lyme disease symptoms (PTLDs) or syndrome (PTLDS), depending on the degree to which the individual's symptoms impact their quality of life. PTLDs occur in a portion of patients diagnosed with chronic Lyme disease (CLD), a controversial term describing different patient populations, diagnosed based on unvalidated tests and criteria. Practitioners should review the evidence for the Lyme disease diagnosis and not overlook unrelated conditions. Current evidence shows that prolonged antibiotic therapy provides little benefit and carries significant risk. Further research to elucidate the mechanisms underlying persistent symptoms after Lyme disease and to understand CLD is needed.

The neonatal intestinal resistome and factors that influence it - a systematic review

BACKGROUND

The intestinal microbiome provides a reservoir for antibiotic resistance genes (ARGs). The neonatal microbiome is more susceptible to disturbance from external factors than the established microbiome.

OBJECTIVES

In this review, we systematically summarise studies which investigated the intestinal resistome in neonates.

DATA SOURCES

MEDLINE and Embase databases were searched.

STUDY ELIGIBILITY CRITERIA

We included original studies which investigated ARGs in stool or rectal swabs in neonates using molecular diagnostics.

METHODS OF DATA SYNTHESIS

Two authors independently extracted data. Data was summarised in tables.

RESULTS

Our search identified 2,701 studies, of which 23 (22 cohorts) were included. The studies show that the neonatal intestine harbours a high abundance and variety of ARGs, even in the absence of direct antibiotic exposure. The most-commonly found ARGs confer resistance to aminoglycosides, beta-lactams, macrolides, tetracyclines or multi-drug resistance. There is evidence that ARGs can be transferred from mothers to neonates. Interestingly, however, compared to mothers, neonates are reported to have a higher abundance of ARGs. One likely reason for this is the bacterial phylogenetic composition with a high abundance of Gammaproteobacteria in neonatal stool. Factors that have been associated with a higher abundance of ARGs are intrapartum and neonatal antibiotic use. Breastfeeding and neonatal probiotic use have been associated with a lower abundance of ARGs. Antibiotics during pregnancy, delivery mode or sex are reported to have little effect. However, this might be because studies were underpowered and because it is difficult to account for effect modifiers.

DISCUSSION

The neonatal intestine seems to have a lower colonisation resistance, which could make it easier for antibiotic-resistant populations to establish themselves. Future studies will help in the development of evidence-based interventions to modulate the abundance of ARGs in neonates, for example, by the use of pre- and probiotics and bacteriophages.

Metagenomics Approaches to Investigate the Neonatal Gut Microbiome

Early infancy is critical for the development of an infant's gut flora. Many factors can influence microbiota development during the pre- and postnatal periods, including maternal factors, antibiotic exposure, mode of delivery, dietary patterns, and feeding type. Therefore, investigating the connection between these variables and host and microbiome interactions in neonatal development would be of great interest. As the "unculturable" era of microbiome research gives way to an intrinsically multidisciplinary field, microbiome research has reaped the advantages of technological advancements in next-generation sequencing, particularly 16S rRNA gene amplicon and shotgun sequencing, which have considerably expanded our knowledge about gut microbiota development during early life. Using omics approaches to explore the neonatal microbiome may help to better understand the link between the microbiome and newborn diseases. Herein, we summarized the metagenomics methods and tools used to advance knowledge on the neonatal microbiome origin and evolution and how the microbiome shapes early and late individuals' lives for health and disease. The way to overcome limitations in neonatal microbiome studies will be discussed.

Pattern of Antibiotic Use in the Perinatal Period in a Public University Hospital in Romania

Background and Objectives: Antibiotics are the most frequently prescribed drugs in hospitals and their prescription is increased during pregnancy and labor. There are limited data about this issue, and the safe use of antibiotics in pregnancy and antibiotic resistance remains a concern. The aim of the study is to evaluate the use of antibiotics among pregnant women attending hospital for five years. Materials and Methods: Antibiotic consumption and treatment information of patients were retrospectively collected from a hospital software program and expressed as defined daily dose (DDD) according to the World Health Organization (WHO) methodology for inpatients between 2017 and 2021. We evaluated antibiotic prescription by name, classes, and Food and Drug Administration (FDA) categories. Results: Antibiotic consumption shows a decreasing trend between 2017 and 2019, but an increasing one between 2020 and 2021. Ceftriaxone was the most prescribed antibiotic in each year, followed by cefixime, amoxicillin, metronidazole, cefuroxime, ampicillin, and ciprofloxacin. We noticed that first- and fourth-generation cephalosporins were not prescribed to these patients. A very small percentage of women in this study received antibiotics such as aminoglycosides; fluoroquinolones were generally contraindicated in the perinatal period. A large percentage of prescriptions were antibiotics classified as category B by the FDA. The most common infections that occurred in the perinatal period were those of the kidney and urinary tract in a higher number than in other studies. Conclusions: Our study shows that many classes of antibiotics used in perinatal women belong to category B antibiotics, the most prescribed being cephalosporins. Because of insufficient safety evidence and the potential for teratogenic effects on the fetus, restricted use among the category C and D antibiotic classes was seen and anticipated. Improving maternal health requires the involvement of healthcare experts in risk assessment and evaluation of existing data for appropriate antibiotic selection, dose, duration of medication, and monitoring.

The Impact of Probiotics, Prebiotics, and Synbiotics during Pregnancy or Lactation on the Intestinal Microbiota of Children Born by Cesarean Section: A Systematic Review

The gut microbiota is a key factor in the correct development of the gastrointestinal immune system. Studies have found differences between the gut microbiota of newborns delivered by cesarean section compared to those vaginally delivered. Our objective was to evaluate the effect of ingestion of probiotics, prebiotics, or synbiotics during pregnancy and/or lactation on the development of the gut microbiota of the C-section newborns. We selected experimental studies in online databases from their inception to October 2021. Of the 83 records screened, 12 met the inclusion criteria. The probiotics used belonged to the genera Lactobacillus, Bifidobacterium, Propionibacterium, and Streptococcus, or a combination of those, with dosages varying between 2 × 10⁶ and 9 × 10¹¹ CFU per day, and were consumed during pregnancy and/or lactation. Probiotic strains were combined with galacto-oligosaccharides, fructo-oligosaccharides, or bovine milk-derived oligosaccharides in the synbiotic formulas. Probiotic, prebiotic, and synbiotic interventions led to beneficial gut microbiota in cesarean-delivered newborns, closer to that in vaginally delivered newborns, especially regarding Bifidobacterium colonization. This effect was more evident in breastfed infants. The studies indicate that this beneficial effect is achieved when the interventions begin soon after birth, especially the restoration of bifidobacterial population. Changes in the infant microbial ecosystem due to the interventions seem to continue after the end of the intervention in most of the studies. More interventional studies are needed to elucidate the optimal synbiotic combinations and the most effective strains and doses for achieving the optimal gut microbiota colonization of C-section newborns.

Human Breast Milk Composition and Function in Human Health: From Nutritional Components to Microbiome and MicroRNAs

Human breast milk (HBM) is not only an indispensable source of nutrients for early human growth and development, supplying components that support infant growth and development, but also contains various essential immunologic components with anti-infectious activities and critical roles in the formation of immunity. It is also known that HBM contains its own unique microbiome, including beneficial, commensal, and potentially probiotic bacteria, that can contribute to infant gut colonization. In addition, HBM-derived extracellular vesicles, exosomes, and microRNA are attracting increasing interest for their potential to transfer to the infant and their role in infant development. In this article, we examine some of the various constituents in HBM and review the evidence supporting their associated health effects and their potential applications in human health.

Bacterial Diversity of Breast Milk in Healthy Spanish Women: Evolution from Birth to Five Years Postpartum

The objective of this work was to characterize the microbiota of breast milk in healthy Spanish mothers and to investigate the effects of lactation time on its diversity. A total of ninety-nine human milk samples were collected from healthy Spanish women and were assessed by means of next-generation sequencing of 16S rRNA amplicons and by qPCR. Firmicutes was the most abundant phylum, followed by Bacteroidetes, Actinobacteria, and Proteobacteria. Accordingly, Streptococcus was the most abundant genus. Lactation time showed a strong influence in milk microbiota, positively correlating with Actinobacteria and Bacteroidetes, while Firmicutes was relatively constant over lactation. 16S rRNA amplicon sequencing showed that the highest alpha-diversity was found in samples of prolonged lactation, along with wider differences between individuals. As for milk nutrients, calcium, magnesium, and selenium levels were potentially associated with Streptococcus and Staphylococcus abundance. Additionally, Proteobacteria was positively correlated with docosahexaenoic acid (DHA) levels in breast milk, and Staphylococcus with conjugated linoleic acid. Conversely, Streptococcus and trans-palmitoleic acid showed a negative association. Other factors such as maternal body mass index or diet also showed an influence on the structure of these microbial communities. Overall, human milk in Spanish mothers appeared to be a complex niche shaped by host factors and by its own nutrients, increasing in diversity over time.

Breast Milk: A Source of Functional Compounds with Potential Application in Nutrition and Therapy

Breast milk is an unbeatable food that covers all the nutritional requirements of an infant in its different stages of growth up to six months after birth. In addition, breastfeeding benefits both maternal and child health. Increasing knowledge has been acquired regarding the composition of breast milk. Epidemiological studies and epigenetics allow us to understand the possible lifelong effects of breastfeeding. In this review we have compiled some of the components with clear functional activity that are present in human milk and the processes through which they promote infant development and maturation as well as modulate immunity. Milk fat globule membrane, proteins, oligosaccharides, growth factors, milk exosomes, or microorganisms are functional components to use in infant formulas, any other food products, nutritional supplements, nutraceuticals, or even for the development of new clinical therapies. The clinical evaluation of these compounds and their commercial exploitation are limited by the difficulty of isolating and producing them on an adequate scale. In this work we focus on the compounds produced using milk components from other species such as bovine, transgenic cattle capable of expressing components of human breast milk or microbial culture engineering.

Acquisition and establishment of the oral microbiota

Acquisition and establishment of the oral microbiota occur in a dynamic process over various stages and involve close and continuous interactions with the host and its environment. In the present review, we discuss the stages of this process in chronological order. We start with the prenatal period and address the following questions: ‘Is the fetus exposed to maternal microbiota during pregnancy?’ and ‘If so, what is the potential role of this exposure?’ We comment on recent reports of finding bacterial DNA in placenta during pregnancies, and provide current views on the potential functions of prenatal microbial encounters. Next, we discuss the physiological adaptations that take place in the newborn during the birth process and the effect of this phase of life on the acquisition of the oral microbiota. Is it really just exposure to maternal vaginal microbes that results in the difference between vaginally and Cesarian section‐born infants? Then, we review the postnatal phase, in which we focus on transmission of microbes, the intraoral niche specificity, the effects of the host behavior and environment, as well as the role of genetic background of the host on shaping the oral microbial ecosystem. We discuss the changes in oral microbiota during the transition from deciduous to permanent dentition and during puberty. We also address the finite knowledge on colonization of the oral cavity by microbes other than the bacterial component. Finally, we identify the main outstanding questions that limit our understanding of the acquisition and establishment of a healthy microbiome at an individual level.

Gut Microbiome: A Potential Modifiable Risk Factor in Biliary Atresia

Biliary atresia (BA) is a fibro-obliterative condition of the biliary tree, presenting in infancy. The bilioenteric conduit formed at Kasai portoenterostomy (KPE), achieves restoration of bile flow in approximately 60% of infants. Even if the operation is successful, cirrhosis and its associated complications are, however, common. BA remains the leading cause for liver transplantation (LT) in children. Antibiotic, choleretic, and steroid therapy post-KPE have not convincingly reduced LT rates. Advances in molecular technology have enabled characterisation of the encoded genes of the gut microbiota (gut microbiome). The gut microbiome plays an important role in host metabolism, nutrition, and immune function, with alterations in its diversity and/or composition, known as dysbiosis, being described in disease states, including liver disease. Liver-gut microbiome exploration in adulthood largely focuses on nonalcoholic liver disease, cirrhosis (mainly alcohol- or viral-based aetiology) and cholestatic liver diseases (eg, primary sclerosing cholangitis), with microbial signatures correlating to disease severity. Investigation of the gut microbiota in BA had been limited to culture-based methodology, but molecular studies are emerging, and although in their infancy, highlight a potential pathogenic role for Enterobacteriaceae and Streptococcus, and a potential beneficial role for Bifidobacteria. Bacterial translocation, and the production of gut microbiome-derived metabolites, are key host-microbiome-mechanistic pathways in liver disease pathogenesis. Microbiome-targeted therapeutics for liver disease are in development, with faecal microbiota transplantation showing promise in cirrhosis. Could the gut microbiome be a novel modifiable risk factor in BA, reducing the need for LT?

Why is COVID-19 less severe in children? A review of the proposed mechanisms underlying the age-related difference in severity of SARS-CoV-2 infections

In contrast to other respiratory viruses, children have less severe symptoms when infected with the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this review, we discuss proposed hypotheses for the age-related difference in severity of coronavirus disease 2019 (COVID-19).Factors proposed to explain the difference in severity of COVID-19 in children and adults include those that put adults at higher risk and those that protect children. The former include: (1) age-related increase in endothelial damage and changes in clotting function; (2) higher density, increased affinity and different distribution of angiotensin converting enzyme 2 receptors and transmembrane serine protease 2; (3) pre-existing coronavirus antibodies (including antibody-dependent enhancement) and T cells; (4) immunosenescence and inflammaging, including the effects of chronic cytomegalovirus infection; (5) a higher prevalence of comorbidities associated with severe COVID-19 and (6) lower levels of vitamin D. Factors that might protect children include: (1) differences in innate and adaptive immunity; (2) more frequent recurrent and concurrent infections; (3) pre-existing immunity to coronaviruses; (4) differences in microbiota; (5) higher levels of melatonin; (6) protective off-target effects of live vaccines and (7) lower intensity of exposure to SARS-CoV-2.

More than Nutrition: Therapeutic Potential of Breast Milk-Derived Exosomes in Cancer

Human breast milk (HBM) is an irreplaceable source of nutrition for early infant growth and development. Breast-fed children are known to have a low prevalence and reduced risk of various diseases, such as necrotizing enterocolitis, gastroenteritis, acute lymphocytic leukemia, and acute myeloid leukemia. In recent years, HBM has been found to contain a microbiome, extracellular vesicles or exosomes, and microRNAs, as well as nutritional components and non-nutritional proteins, including immunoregulatory proteins, hormones, and growth factors. Especially, the milk-derived exosomes exert various physiological and therapeutic function in cell proliferation, inflammation, immunomodulation, and cancer, which are mainly attributed to their cargo molecules such as proteins and microRNAs. The exosomal miRNAs are protected from enzymatic digestion and acidic conditions, and play a critical role in immune regulation and cancer. In addition, the milk-derived exosomes are developed as drug carriers for delivering small molecules and siRNA to tumor sites. In this review, we examined the various components of HBM and their therapeutic potential, in particular of exosomes and microRNAs, towards cancer.

Dietary Milk Fat Globule Membrane Restores Decreased Intestinal Mucosal Barrier Development and Alterations of Intestinal Flora in Infant-Formula-Fed Rat Pups

SCOPE

Milk fat globule membrane (MFGM), which contains abundant polar lipids and glycoproteins, can narrow the gap in growth and development between breast-fed and infant-formula-fed babies. The objective of this study is to evaluate the effect of MFGM supplementation in infant formula on intestinal epithelium maturation, tight junctions, and gut colonization in rat pups.

METHODS AND RESULTS

Sprague Dawley rat pups consume one of the five diets from postnatal day 8, including rat breastfeeding (BF), infant formula (IF), and infant formula containing MFGM at 260 mg kg^-1 body weight (BW), 520 mg kg^-1 BW, or 1040 mg kg^-1 BW. Results show that MFGM supplementation in infant formula can facilitate intestinal mucosal barrier maturation via promoting intestinal proliferation and differentiation, and increasing tight junction proteins. In addition, compared with that of the IF pups, the intestinal flora composition of MFGM-supplemented pups is more similar to that of BF pups.

CONCLUSION

MFGM supplementation in infant formula can restore the intestinal development in infant-formula-fed pups, which suggests that the supplementation of MFGM in infant formula can better mimic breast milk.

The Impact of the Postpartum "Doing-the-Month" Practice on Human Milk Microbiota: A Pilot Study in Taiwan

Human milk microorganisms could benefit the healthy development of the immune system in infants. In Asia, the practice of “doing-the-month” indicates a month-long period of postpartum recuperation for new mothers. This is composed of cultural practices, traditional beliefs, behavioral, dietary, and herbal therapies. In this pilot study, we evaluated the effect of “doing-the-month” on the human milk microbiota using a molecular approach. We collected two “doing-the-month” milk groups from randomly recruited mothers who had completed their “doing-the-month” program in either postpartum care center A (milk-PCA, n = 14) or postpartum care center B (milk-PCB, n = 27) for 20 to 30 days. As for the control group, milk samples were selected from postpartum mothers (milk-H, n = 46), who did not conduct the “doing-the-month” program. We found that the “doing-the-month” milk samples were associated with more diverse and unique milk microbiota and that these samples were also linked with more abundant Lactobacillus (milk-PCB) and prevalent Bifidobacteria (milk-PCA and milk-PCB). In addition, the milk samples from “doing-the-month” mothers could be enriched with more Archaea bacterial members, but the “non-doing-the-month” milk samples were enriched with more common skin-, oral-, and environmental-related bacterial members. This study highlights the impact maternal practices may have on the milk microbiome. More research is needed to investigate the effects this may have on infant immune health.

Analysis of the human breast milk microbiome and bacterial extracellular vesicles in healthy mothers

The microbiota of human breast milk (HBM) contribute to infant gut colonization; however, whether bacterial extracellular vesicles (EVs) are present in HBM or might contribute to this process remains unknown. In this study, we characterized the HBM microbiota of healthy Korean mothers and measured the key bacteria likely affecting infant gut colonization by analyzing both the microbiota and bacterial EVs. A total of 22 HBM samples were collected from lactating mothers. The DNA of bacteria and bacteria-derived EVs was extracted from each sample. In alpha-diversity analyses, bacterial samples showed higher richness and evenness than bacterial EV samples, and beta-diversity analyses showed significant differences between bacteria and bacterial EVs within identical individual samples. Firmicutes accounted for the largest proportion among the phyla, followed by Proteobacteria, Bacteroidetes, and Actinobacteria, in both bacteria and bacterial EV samples. At the genus level, Streptococcus (25.1%) and Staphylococcus (10.7%) were predominant in bacterial samples, whereas Bacteroides (9.1%), Acinetobacter (6.9%), and Lactobacillaceae(f) (5.5%) were prevalent in bacterial EV samples. Several genera, including Bifidobacterium, were significantly positively correlated between the two samples. This study revealed the diverse bacterial communities in the HBM of healthy lactating mothers, and found that gut-associated genera accounted for a high proportion in bacterial EV samples. Our findings suggest the existence of key bacteria with metabolic activity that are independent of the major bacterial populations that inhabit HBM, and the possibility that EVs derived from these bacteria are involved in the vertical transfer of gut microbiota.

Human breast milk contains a diverse population of bacteria, and tiny membrane-bound packages called extracellular vesicles (EVs) released by bacteria, both of which may contribute to the establishment of beneficial bacterial populations in the infant gut. The microbes that live naturally in our gut are believed to be involved in the development of a healthy immune system, as well as supporting digestion and influencing other aspects of health. Su Yeong Kim and Dae Yong Yi at Chung-Ang University Hospital in Seoul, South Korea, performed a detailed analysis of DNA from bacteria and EVs in breast milk produced by healthy mothers. In addition to categorising the diverse bacterial populations, the study confirms the presence of EVs in human breast milk. These EVs may influence the transmission of bacteria from the mother into an infant’s gut.

Study protocol for the ABERRANT study: antibiotic-induced disruption of the maternal and infant microbiome and adverse health outcomes - a prospective cohort study among children born at term

INTRODUCTION

There is compositional overlap between the maternal intestinal microbiome, the breast milk microbiome and the infant oral and intestinal microbiome. Antibiotics cause profound changes in the microbiome. However, the effect of intrapartum and early-life antibiotics on the maternal intestinal and breast milk microbiome, and the infant oral and intestinal microbiome, and whether effects are only short term or persist long term remain uncertain.

METHODS AND ANALYSES

In this prospective cohort study, we will use metagenomic sequencing to determine: (1) the effect of intrapartum antibiotics on the composition of the breast milk, and the infant oral and intestinal microbiome, including the development and persistence of antibiotic resistance; (2) the effect of antibiotic exposure in the first year of life on the composition of the infant oral and intestinal microbiome, including the development and persistence of antibiotic resistance; (3) the effect of disruption of the infant oral and intestinal microbiome on health outcomes and (4) the compositional overlap between the maternal intestinal microbiome, the breast milk microbiome and the infant oral and intestinal microbiome.

ETHICS AND DISSEMINATION

The ABERRANT study has been approved by the commission cantonale d'éthique de la recherche sur l'être humain (CER-VD) du Canton de Vaud (#2019-01567). Outcomes will be disseminated through publication and will be presented at scientific conferences.

TRIAL REGISTRATION NUMBER

NCT04091282.

Establishing a high microbial load maternal-offspring asthma model in adult mice

BACKGROUND

Although it is widely accepted that the "hygiene hypothesis" explains the increased incidence of asthma, the lack of suitable animal models hinders further in-depth studies of the underlying molecular immune mechanisms. Therefore, we aimed to develop a robust mouse asthma model to investigate the role of bacteria in preventing asthma.

METHODS

BALB/c female mice were fed a mixture of eight common bacterial lysates (BL; Broncho-Vaxom®) and a commercial probiotic (Bifidobacterium tetravaccine tablets) at different concentrations before and during pregnancy to simulate different microbial load levels. Faeces from the mother mice were subjected to bacterial 16S rRNA sequencing to quantify the maternal microbial load. TLR2/4 expression and the proportion of regulatory T cells (Tregs) in the intestinal tract of female mice were determined, and the safety of the microbial load was evaluated. An asthma model was established in the offspring mice after weaning, and the extent of pulmonary pathological changes and Treg proportion were evaluated.

RESULTS

A BL concentration of 1 mg/kg enriched the intestinal flora, increased the proportion of Tregs, and increased the expression of TLR2/4 in the maternal mice. The proportion of peripheral blood Tregs was increased, whereas the risk of asthma decreased only in the offspring from mothers with a high microbial load relative to control mice.

CONCLUSION

This study established a safe and stable high microbial load maternal-offspring mouse asthma model, laying the foundation for a study on the molecular mechanism underlying the protective effects of a high microbial load against asthma.

Effect of intrapartum antibiotics on the intestinal microbiota of infants: a systematic review

INTRODUCTION

The use of intrapartum antibiotic prophylaxis (IAP) has become common practice in obstetric medicine and is used in up to 40% of deliveries. Despite its benefits, the risks associated with exposing large numbers of infants to antibiotics, especially long-term effects on health through changes in the microbiota, remain unclear. This systematic review summarises studies that have investigated the effect of IAP on the intestinal microbiota of infants.

METHODS

A systematic search in Ovid MEDLINE was used to identify original studies that investigated the effect of IAP on the intestinal microbiota in infants. Studies were excluded if: they included preterm infants, the antibiotic regimen was not specified, antibiotics were used for indications other than prophylaxis, probiotics were given to mothers or infants, or antibiotics were given to infants.

RESULTS

We identified six studies, which investigated a total of 272 infants and included 502 stool samples collected up to 3 months of age. In all the studies, IAP was given for group B streptococcus (GBS) colonisation. Infants who were exposed to GBS IAP had a lower bacterial diversity, a lower relative abundance of Actinobacteria, especially Bifidobacteriaceae, and a larger relative abundance of Proteobacteria in their intestinal microbiota compared with non-exposed infants. Conflicting results were reported for the phyla Bacteroidetes and Firmicutes.

CONCLUSIONS

GBS IAP has profound effects on the intestinal microbiota of infants by diminishing beneficial commensals. Such changes during the early-life 'critical window' during which the intestinal microbiota and the immune response develop concurrently may have an important influence on immune development. The potential long-term adverse consequences of this on the health of children warrant further investigation.

Atopic dermatitis in a cohort of West Highland white terriers in Switzerland. Part II: estimates of early life factors and heritability

BACKGROUND

There is accumulating evidence in studies of allergic diseases in humans and dogs that environmental experiences during the first months of life can influence the development of allergic disease. No prospective study has evaluated this in veterinary medicine.

HYPOTHESIS/OBJECTIVES

To assess early-life risk factors for canine atopic dermatitis (cAD) and estimate its heritability.

ANIMALS

A West Highland white terrier birth cohort (n = 107) followed up to three years of age recording the development of cAD.

METHODS AND MATERIALS

The effect of environmental factors [house dust mites (HDM), hygiene, feeding, lifestyle] and early-life determinants [breeder, mode of delivery, birth season, sex, litter size, early-life immunoglobulin E (IgE) levels] were assessed, using Stata SE 15.1 statistical analysis. Heritabilities were estimated using the R program packages MCMCglmm and QGglmm.

RESULTS

Maternal allergic status [P = 0.013, odds ratio (OR 3.3)], male sex (P = 0.06), mode of delivery (P = 0.12), breeder (P = 0.06), presence of HDM (P = 0.11) and environmental hygiene level (P = 0.15) were identified as possible influence factors by bivariate analyses. In the multivariate analysis the male sex was significantly associated with the development of cAD in the offspring (P = 0.03, OR 2.4). The heritabilities on the observed scale were 0.31 (direct), 0.04 (maternal genetic effects) and 0.03 (maternal permanent environmental effects).

CONCLUSION AND CLINICAL IMPORTANCE

These results suggest that several environmental factors could influence the development of cAD but clearly demonstrate the genetic influence of the individual and the dam. Further studies are needed to identify specific environmental factors, which could be potential targets for primary disease intervention.

Breast milk microbiota: A review of the factors that influence composition

Breastfeeding is associated with considerable health benefits for infants. Aside from essential nutrients, immune cells and bioactive components, breast milk also contains a diverse range of microbes, which are important for maintaining mammary and infant health. In this review, we summarise studies that have investigated the composition of the breast milk microbiota and factors that might influence it. We identified 44 studies investigating 3105 breast milk samples from 2655 women. Several studies reported that the bacterial diversity is higher in breast milk than infant or maternal faeces. The maximum number of each bacterial taxonomic level detected per study was 58 phyla, 133 classes, 263 orders, 596 families, 590 genera, 1300 species and 3563 operational taxonomic units. Furthermore, fungal, archaeal, eukaryotic and viral DNA was also detected. The most frequently found genera were Staphylococcus, Streptococcus Lactobacillus, Pseudomonas, Bifidobacterium, Corynebacterium, Enterococcus, Acinetobacter, Rothia, Cutibacterium, Veillonella and Bacteroides. There was some evidence that gestational age, delivery mode, biological sex, parity, intrapartum antibiotics, lactation stage, diet, BMI, composition of breast milk, HIV infection, geographic location and collection/feeding method influence the composition of the breast milk microbiota. However, many studies were small and findings sometimes contradictory. Manipulating the microbiota by adding probiotics to breast milk or artificial milk offers an exciting avenue for future interventions to improve infant health.

Biological sex influences antibody responses to routine vaccinations in the first year of life

AIM

We investigated the effect of early-life factors, namely sex, delivery mode, feeding method and antibiotic exposure, on antibody responses to routine vaccinations administered during the first year of life.

METHODS

One and seven months after the primary course of routine vaccines and 1 month after routine vaccines at 12 months of age, antibodies against 26 vaccine antigens were measured in 398 healthy infants. The geometric mean concentration (GMC) of antibodies (adjusted for effect modifiers with multiple linear regression) and the seroprotection rate for each vaccine were compared for each early-life factor.

RESULTS

Sex had an influence on GMCs. Antibody concentrations were significantly lower at 7 months of age in females for tetanus and filamentous haemagglutinin and at 13 months of age for pertactin. In contrast, at 13 months of age, antibody concentrations were significantly higher in females for polio type 3, pneumococcal serotype 6A and measles. Sex did not have an influence on seroprotection rates. Delivery mode, feeding method and antibiotic exposure did not exert a substantial influence on vaccine antibody concentrations.

CONCLUSION

There is a difference between males and females in the humoral response to routine vaccinations in the first year of life.

Influence of Leptin and Adiponectin Supplementation on Intraepithelial Lymphocyte and Microbiota Composition in Suckling Rats

Dietary components in early life play a role in both microbiota and intestinal immune system maturation in mammalian species. Adipokines, as endogenously produced hormones from breast milk, may have an impact on this process. The aim of the present study was to establish the influence of leptin and adiponectin supplementation during suckling on the intraepithelial lymphocyte composition, intestinal barrier function, intestinal gene expression, and gut microbiota in rat. For this purpose, newborn Wistar rats were supplemented daily with leptin, adiponectin, or whey protein concentrate during the first 21 days of life. Lymphocyte composition was established by immunofluorescence staining and flow cytometry analysis; intestinal gene expression by real-time PCR and cecal microbiota were analyzed through 16S rRNA gene sequencing. Although leptin and adiponectin were able to increase the Tc TCRαβ⁺ and NKT cell proportion, they decreased the NK cell percentage in IEL. Moreover, adipokine supplementation differentially modified CD8⁺ IEL. While the supplementation of leptin increased the proportion of CD8αα⁺ IEL (associated to a more intestinal phenotype), adiponectin enhanced that of CD8αβ⁺ (related to a peripheral phenotype). Furthermore, both adipokines enhanced the gene expression of TNF-α, MUC-2, and MUC-3, and decreased that of FcRn. In addition, the adipokine supplementations decreased the abundance of the Proteobacteria phylum and the presence of Blautia. Moreover, leptin-supplemented animals had lower relative abundance of Sutterella and a higher proportion of Clostridium genus, among others. However, supplementation with adiponectin resulted in lower abundance of the Roseburia genus and a higher proportion of the Enterococcus genus. In conclusion, the supplementation with leptin and adiponectin throughout the suckling period had an impact on both the IEL composition and the gut microbiota pattern, suggesting a modulatory role of these adipokines on the development of intestinal functionality.

Immunomodulatory and Prebiotic Effects of 2'-Fucosyllactose in Suckling Rats

Human milk oligosaccharides are unconjugated complex glycans present in high concentration in human milk that serve as pre-biotics and immunomodulators. They are not primarily absorbed or metabolized by the infant and reach the lower part of the intestinal tract unaltered. One of the main oligosaccharides found in human milk is 2'-fucosyllactose (2'-FL). This study aimed to investigate the effects of daily oral administration of 2'-FL in healthy suckling rats. From days 2 to 16 of life, rats were daily given the oligosaccharide (2'-FL) or vehicle (REF), weighed and their stool characteristics were assessed. On days 8 and 16 of life the morphometry, intestinal architecture, and cytokine release, mesenteric lymph nodes cell composition, plasma immunoglobulin concentrations, fecal microbiota composition, cecal short-chain fatty acids content, and the urinary metabolic profile were assessed. Animals given 2'-FL showed higher plasma IgG and IgA and more T cell subsets in the mesenteric lymph nodes on day 16. Moreover, at intestinal level, villus heights, and areas were increased on day 8. Cecal samples displayed a higher Lactobacillus proportion and a different urinary metabolic profile was observed on day 8, and a higher proportion of butyrate on day 16. In conclusion, supplementation of 2'-FL in early life has a pre-biotic and intestinal trophic effect and promotes maturation of the immune system.

Dysbiosis associated with acute helminth infections in herbivorous youngstock - observations and implications

A plethora of data points towards a role of the gastrointestinal (GI) microbiota of neonatal and young vertebrates in supporting the development and regulation of the host immune system. However, knowledge of the impact that infections by GI helminths exert on the developing microbiota of juvenile hosts is, thus far, limited. This study investigates, for the first time, the associations between acute infections by GI helminths and the faecal microbial and metabolic profiles of a cohort of equine youngstock, prior to and following treatment with parasiticides (ivermectin). We observed that high versus low parasite burdens (measured via parasite egg counts in faecal samples) were associated with specific compositional alterations of the developing microbiome; in particular, the faecal microbiota of animals with heavy worm infection burdens was characterised by lower microbial richness, and alterations to the relative abundances of bacterial taxa with immune-modulatory functions. Amino acids and glucose were increased in faecal samples from the same cohort, which indicated the likely occurrence of intestinal malabsorption. These data support the hypothesis that GI helminth infections in young livestock are associated with significant alterations to the GI microbiota, which may impact on both metabolism and development of acquired immunity. This knowledge will direct future studies aimed to identify the long-term impact of infection-induced alterations of the GI microbiota in young livestock.

The STRONG Kids 2 Birth Cohort Study: A Cell-to-Society Approach to Dietary Habits and Weight Trajectories across the First 5 Years of Life

BACKGROUND

Dietary habits formed during the first 5 y of life portend lifelong eating patterns.

OBJECTIVE

The Synergistic Theory Research Obesity and Nutrition Group (STRONG) Kids 2 birth cohort study aimed to examine multilevel predictors of weight trajectories and dietary habits including individual biology, child socioemotional and behavioral characteristics, family environment, and child care environment over the first 5 y of life. This report describes recruitment strategies, an overview of survey measures, and basic descriptive statistics of the cohort.

METHODS

The cohort includes 468 mothers and their offspring. A brief survey was completed at a 1-wk home visit including child's birth weight, intent to breastfeed, collection of an infant stool sample, and additional contact information should the family move. Mothers completed surveys including diet, child temperament, family environment, and child care when their child was 6 wk, 3, 12, 18, 24, 36, 48, and 60 mo of age. Height and weight of the mother and child were collected at each visit. Stool samples of the child were collected at each visit as well as saliva at 1 visit.

RESULTS

Close to half of the mothers were either overweight (24.2%) or obese (25.2%) prepregnancy. At 6 wk of age, 32.9% of the children were overweight and 31.4% were obese based on direct measurement.

CONCLUSIONS

The STRONG Kids 2 research team has adopted a socioecological model that accounts for multiple influences on children's health including biological, child social and behavioral, family household organization, and community factors. The study is limited by a relatively educated and nondiverse sample. However, variations in maternal and child weight may inform future prevention programs and policy aimed at improving the diet and health of children under the age of 5 y.This trial was registered at clinicaltrials.gov as NCT03341858.

Filling the Gaps: Current Research Directions for a Rational Use of Probiotics in Preterm Infants

The use of probiotics among very low-birth-weight infants is constantly increasing, as probiotics are believed to reduce the incidence of severe diseases such as necrotizing enterocolitis and late-onset sepsis and to improve feeding tolerance. However, despite the enthusiasm towards these products in neonatal medicine, theoretical knowledge and clinical applications still need to be improved. The purpose of this review is to give an overview of the most important gaps in the current literature about potential uses of probiotics in preterm infants, highlighting promising directions for future research. Specifically, further well-designed studies should aim at clarifying the impact of the type of feeding (mother's milk, donor milk, and formula) on the relationship between probiotic supplementation and clinical outcome. Moreover, future research is needed to provide solid evidence about the potential greater efficacy of multi-strain probiotics compared to single-strain products. Safety issues should also be addressed properly, by exploring the potential of paraprobiotics and risks connected to antibiotic resistance in preterm infants. Last, in light of increasing commercial and public interests, the long-term effect of routine consumption of probiotics in such a vulnerable population should be also evaluated.