The neonatal bowel microbiome in health and infection

Influence of an Early Human Milk Diet on the Duration of Parenteral Nutrition and Incidence of Late-Onset Sepsis in Very Low Birthweight (VLBW) Infants: A Systematic Review

Introduction: Human milk is the preferred source of enteral nutrition for very low birthweight (VLBW) infants, and it possibly decreases dependence on parenteral nutrition (PN) and reduces incidence of late-onset sepsis (LOS). No systematic review to date has specifically addressed the value of early versus late introduction of human milk diet (HMD) on duration of PN and incidence of LOS among VLBW infants. Objective: To review the evidence for an early versus late introduction of HMD on duration of PN and incidence of LOS in VLBW infants. Method: Preferred reporting items for systematic reviews and meta-analysis-guided search of EMBASE and PubMed/Medline databases was conducted for this systematic review using phrases addressing population, intervention, comparator, and outcome framework to identify articles published over the past two decades without language restrictions. Full-text articles (both observational and randomized) that studied an early versus late initiation of HMD were included. Mean difference (MD) and relative risk (RR) with 95% confidence intervals (CIs) were calculated for PN and LOS. Quality of evidence was analyzed using UK National Service Framework and the risk-of-bias was assessed using Robvis®. Results: One randomized controlled trial (RCT) and two observational studies (two English and one Chinese) recruited 474 VLBW infants (455 analyzed). Among an intrauterine growth-restricted cohort enrolled in the RCT (n = 72), early HMD resulted in statistically significant reduction in PN dependence. However, no statistically significant difference was found in LOS. Two observational studies found similar reductions in PN duration and LOS incidence among the early HMD cohort. One observational study reported significant PN reduction; however, the incidence of LOS did not reach statistical significance in either case. Conclusion: An early HMD may reduce the duration of PN for a growth-restricted VLBW cohort. Observational studies suggesting reduced PN and LOS from early HMD endorse the need for bioactivity-focused human milk research. Variations in feeding guidelines among VLBW infants have the potential to influence neonatal outcomes significantly.

2022 Fleming Prize Lecture: diet-microbe-host interaction in early life

The last decade has witnessed a meteoric rise in research focused on characterizing the human microbiome and identifying associations with disease risk. The advent of sequencing technology has all but eradicated gel-based fingerprinting approaches for studying microbial ecology, while at the same time traditional microbiological culture is undergoing a renaissance. Although multiplexed high-throughput sequencing is relatively new, the discoveries leading to this are nearly 50 years old, coinciding with the inaugural Microbiology Society Fleming Prize lecture. It was an honour to give the 2022 Fleming Prize lecture and this review will cover the topics from that lecture. The focus will be on the bacterial community in early life, beginning with term infants before moving on to infants delivered prematurely. The review will discuss recent work showing how human milk oligosaccharides (HMOs), an abundant but non-nutritious component of breast milk, can modulate infant microbiome and promote the growth of Bifidobacterium spp. This has important connotations for preterm infants at risk of necrotizing enterocolitis, a devastating intestinal disease representing the leading cause of death and long-term morbidity in this population. With appropriate mechanistic studies, it may be possible to harness the power of breast milk bioactive factors and infant gut microbiome to improve short- and long-term health in infants.

The Association between Prematurity, Antibiotic Consumption, and Mother-Infant Attachment in the First Year of Life

Antibiotics have individual and public-health drawbacks. Nevertheless, mother-infant attachment quality and maternal sensitivity are associated with antibiotic use. Ambivalent-attached infants are more likely to consume antibiotics than other infants. Conceivably, the emotional over-externalization of ambivalent-attached infants and maternal anxiety when infants are ill raise concerns in healthcare professionals, leading to antibiotic over-prescriptions. However, because infants prematurely born, particularly those with less than 32 weeks of gestation, are under more accurate health vigilance, the impact of infant and maternal behavior on antibiotic prescription may vanish in this sample. To test this hypothesis, we performed a longitudinal study to compare antibiotic use and the quality of mother-infant attachment in three groups: 86 infants born at full-term, 44 moderate-to-late preterm infants (32-36 gestation weeks), and 58 very-to-extreme preterm infants (<32 gestation weeks). Infants' attachment was observed with the Ainsworth Strange Situation's experimental paradigm at 12 months of corrected age. Findings indicate that infant attachment strategy is associated with antibiotics uptake, but results vary across samples. The proportion of infants that used antibiotics is highest among ambivalent-attached infants in the full-term sample but highest among avoidant-attached infants in the very-to-extreme premature sample. Moreover, higher infant gestational age and lower maternal sensitivity determine higher antibiotic use.

The role of breastfeeding as a protective factor against the development of the immune-mediated diseases: A systematic review

INTRODUCTION

Breast milk is rich in nutrients and immunological factors capable of protecting infants against various immunological diseases and disorders. The current systematic review has been framed with the objective of studying the role of breastfeeding as a protective factor against the development of immune-mediated diseases.

METHODS

The database and website searches were performed using PubMed, PubMed Central, Nature, Springer, Nature, Web of Science, and Elsevier. The studies were scrutinized based on the nature of participants and the nature of disease considered. The search was restricted to infants with immune-mediated diseases such as diabetes mellitus, allergic conditions, diarrhoea, and rheumatoid arthritis.

RESULTS

We have included 28 studies, out of which seven deal with diabetes mellitus, two rheumatoid arthritis, five studies about Celiac Disease, twelve studies about allergic/ asthma/wheezing conditions and one study on each of the following diseases: neonatal lupus erythematosus and colitis.

DISCUSSION

Based on our analysis, breastfeeding in association with the considered diseases was found to be positive. Breastfeeding is involved as protective factor against various diseases. The role of breastfeeding in the prevention of diabetes mellitus has been found to be significantly higher than for other diseases.

Comparative effects of fresh and sterile fecal microbiota transplantation in an experimental animal model of necrotizing enterocolitis

INTRODUCTION

Necrotizing Enterocolitis (NEC) is a serious intestinal disease that affects premature neonates, causing high mortality, despite the technological development in neonatal intensive care, with antibiotics, parenteral nutrition, surgery, and advanced life support. The correction of dysbiosis with fecal microbiome transplantation (FMT) has shown beneficial effects in experimental models of the disease. The different forms of administration and conservation of FMT and mixed results depending on several factors lead to questions about the mechanism of action of FMT. This study aimed to compare the effectiveness of fresh, sterile FMT and probiotic treatment under parameters of inflammation, oxidative stress, and tissue damage in a neonatal model of NEC.

METHODS

One-day-old Wistar rats were used to induce NEC model. Animals were divided in five groups: Control + saline; NEC + saline; NEC + fresh FMT; NEC + sterile FMT and NEC+ probiotics. Parameters of inflammatory response and oxidative damage were measured in the gut, brain, and serum. It was also determined gut histopathological alterations.

RESULTS

Proinflammatory cytokines were increased in the NEC group, and IL-10 levels decreased in the gut, brain, and serum. Fresh and sterile FMT decreased inflammation when compared to the use of probiotics. Oxidative and histological damage to the intestine was apparent in the NEC group, and both FMT treatments had a protective effect.

CONCLUSION

Fresh and sterile FMT effectively reduced the inflammatory response, oxidative damage, and histological alterations in the gut and brain compared to an experimental NEC model.

Changes in intestinal microflora and its metabolites underlie the cognitive impairment in preterm rats

Background

The brain development of preterm infants is easily affected by various adverse extrauterine factors and complications, resulting in abnormal neurological and cognitive development. Recent studies have found that there is a significant correlation between intestinal microbial changes and cognitive behavior. Nevertheless, the correlation between the cognitive impairment and abnormal changes of intestinal microflora in the preterm newborn has been rarely elucidated.

Aim

To analyze the differences of fecal intestinal flora, short chain fatty acids (SCFAs) and microbiota-gut-brain axis (MGBA)-related serum factors between preterm birth with and without cognitive impairment.

Methods

Healthy female rats (body weight 410 ± 40 g) of 16-17 days of gestation were selected for the establishment of preterm cognitive impairment model and screened by Morris water maze navigation experiments. The pathological change of rat hippocampus was confirmed by HE staining. The abundance of fecal intestinal microflora was determined by 16sRNA sequencing, while the contents of fecal SCFAs were examined by gas chromatography.

Results

Compared with the control group, the cognitive impairment group had decreased abundance and diversity of intestinal microflora and increased abundance of Proteobacteria at the level of phylum. While the abundances of Alistipes, Bacteroides, Prevotella, and Lactobacillus decreased significantly at the level of order, family, and genus, the abundances of Staphylococcaceae, Enterococci, Psychrobacter, and Oligella increased significantly. Moreover, the levels of total SCFAs and acetic acid in the disease group were significantly lower. The fecal abundance of acetic acid was positively correlated with that of Lactobacillaceae or Peptostreptococcaceae, and negatively correlated with that of Aerococcaceae, and Alcaligenaceae in disease rats. Furthermore, cognitive impairment caused significantly decreased levels of 5-HT, GABA, and BDNF, and increased levels of GR, CRH, IL-6, and TNF-α in rat blood.

Conclusion

Alterations in intestinal microflora structure and the abundances of SCFAs contributed substantially to the cognitive impairment in preterm rats, which was associated with significant changes in MGBA-related soluble factors.

Randomized, Double-Blind, Placebo-Controlled Study to Assess the Effect of Two Probiotics on the Preterms' Gut Microbiota

OBJECTIVE

To evaluate the effect of a new probiotic strain combination, Ligilactobacillus salivarius subsp infantis PS11603 and Bifidobacterium longum PS10402, on gut bacterial colonization of preterm infants.

METHODS

A randomized, double-blind, placebo-controlled study was conducted in preterm infants from 28 weeks + 0days to 30 weeks + 6days of gestation. Thirty preterm infants were randomly selected after birth to receive either probiotics or placebo. Stool samples were collected before product intake and then sequentially during the first weeks of their admission. Classical microbiological, metagenomics and multiplex immunological analyses were performed to assess the bacterial and immune profile of the samples.

RESULTS

Twenty-seven infants completed the study (14 vs 13, probiotic and placebo groups). A higher number of participants were colonized by Lactobacilli in the probiotic group than in the placebo group (93% vs 46%; P  = 0.013). Similar results were obtained when analysing bifidobacterial colonization (100% vs 69%; P  = 0.041). Earlier colonization was observed in the probiotics group versus the placebo group, specifically 5 weeks for Lactobacillus and 1 week for Bifidobacterium. Although no effect was observed in the faecal immunological profile, a decreasing trend could be observed in Th17 response during the first week of probiotic treatment. None of the adverse events (AEs) registered were related to product intake.

CONCLUSION

Probiotic supplementation with L salivarius PS11603 and B longum subsp. infantis PS10402 enhanced an earlier colonization of Lactobacillus and Bifidobacterium in preterm infants' guts in 5 and 1 week, respectively. A higher number of infants were colonized by Lactobacilli with the probiotics' intake at the end of the study.

From Intrauterine to Extrauterine Life-The Role of Endogenous and Exogenous Factors in the Regulation of the Intestinal Microbiota Community and Gut Maturation in Early Life

Differentiation of the digestive tube and formation of the gut unit as a whole, are regulated by environmental factors through epigenetic modifications which enhance cellular plasticity. The critical period of DNA imprinting lasts from conception until approximately the 1,000th day of human life. During pregnancy, besides agents that may directly promote epigenetic programming (e.g., folate, zinc, and choline supplementation), some factors (e.g., antibiotic use, dietary components) can affect the composition of the mother's microbiota, in turn affecting the fetal microbiome which interacts with the offspring's intestinal epithelial cells. According to available literature that confirms intrauterine microbial colonization, the impact of the microbiome and its metabolites on the genome seems to be key in fetal development, including functional gut maturation and the general health status of the offspring, as well as later on in life. Although the origin of the fetal microbiome is still not well-understood, the bacteria may originate from both the vagina, as the baby is born, as well as from the maternal oral cavity/gut, through the bloodstream. Moreover, the composition of the fetal gut microbiota varies depending on gestational age, which in turn possibly affects the regulation of the immune system at the barrier between mother and fetus, leading to differences in the ability of microorganisms to access and survive in the fetal environment. One of the most important local functions of the gut microbiota during the prenatal period is their exposure to foreign antigens which in turn contributes to immune system and tissue development, including fetal intestinal Innate Lymphoid Cells (ILCs). Additional factors that determine further infant microbiome development include whether the infant is born premature or at term, the method of delivery, maternal antibiotic use, and the composition of the mother's milk, among others. However, the latest findings highlight the fact that a more diverse infant gut microbiome at birth facilitates the proliferation of stem cells by microbial metabolites and accelerates infant development. This phenomenon confirms the unique role of microbiome. This review emphasizes the crucial perinatal and postnatal factors that may influence fetal and neonatal microbiota, and in turn gut maturation.

Probiotics in Pediatrics. A Review and Practical Guide

The potential benefit of the administration of probiotics in children has been studied in many settings globally. Probiotics products contain viable micro-organisms that confer a health benefit on the host. Beneficial effects of selected probiotic strains for the management or prevention of selected pediatric conditions have been demonstrated. The purpose of this paper is to provide an overview of current available evidence on the efficacy of specific probiotics in selected conditions to guide pediatricians in decision-making on the therapeutic or prophylactic use of probiotic strains in children. Evidence to support the use of certain probiotics in selected pediatric conditions is often available. In addition, the administration of probiotics is associated with a low risk of adverse events and is generally well tolerated. The best documented efficacy of certain probiotics is for treatment of infectious gastroenteritis, and prevention of antibiotic-associated, Clostridioides difficile-associated and nosocomial diarrhea. Unfortunately, due to study heterogeneity and in some cases high risk of bias in published studies, a broad consensus is lacking for specific probiotic strains, doses and treatment regimens for some pediatric indications. The current available evidence thus limits the systematic administration of probiotics. The most recent meta-analyses and reviews highlight the need for more well-designed, properly powered, strain-specific and dedicated-dose response studies.

IL-17-related signature genes linked to human necrotizing enterocolitis

Objective

Necrotizing enterocolitis (NEC) is the most frequent life-threatening gastrointestinal disease experienced by premature infants in neonatal intensive care units all over the world. The objective of the present study was to take advantage of RNA-Seq data from the analysis of intestinal specimens of preterm infants diagnosed with NEC. Function enrichments with Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes were used to analyse previous data in order to identify biological and functional processes, which could provide more insight into the pathogenesis of NEC in infants.

Results

Gene set enrichment analysis indicated that the most significant biological pathways over-represented in NEC neonates were closely associated with innate immune functions. One of the striking observations was the highly modulated expression of inflammatory genes related to the IL-17 pathway including such as pro-inflammatory cytokines (CXCL8), chemokines (CXCL5 and CXCL10) and antimicrobials (DEF5A, DEF6A, LCN2, NOS2) in the intestine of neonates diagnosed with NEC. Interestingly, the increase in IL-17 expression appeared to be under the IL-17F form, as reported in Crohn's disease, another inflammatory bowel disease. Further investigation is thus still needed to determine the precise role of IL-17F and its downstream targets in NEC.

Maternal breastmilk, infant gut microbiome and the impact on preterm infant health

AIM

This narrative review summarises the benefits of maternal breastmilk to both the infant and the mother, specifically the benefits that relate to modification of the infant microbiome, and how this might vary in the preterm infant.

METHODS

We used PubMed to primarily identify papers, reviews, case series and editorials published in English until May 2020. Based on this, we report on the components of breastmilk, their associated hypothesised benefits and the implications for clinical practice.

RESULTS

Breastmilk is recommended as the exclusive diet for newborn infants because it has numerous nutritional and immunological benefits. Additionally, exposure to the maternal breastmilk microbiome may confer a lasting effect on gut health. In the preterm infant, breastmilk is associated with a significant reduction in necrotising enterocolitis, an inflammatory gastrointestinal disease and reduction in other key morbidities, together with improved neurodevelopmental outcomes.

CONCLUSION

These impacts have long-term benefits for the child (and the mother) even after weaning. This benefit is likely due, in part, to modification of the infant gut microbiome by breastmilk microbes and bioactive components, and provide potential areas for research and novel therapies in preterm and other high-risk infants.

The association between enteric viruses and necrotizing enterocolitis

Studies on necrotizing enterocolitis (NEC) have not largely focused on enteric viruses. In order to demonstrate the association between enteric viruses and NEC, stool specimens of 51 neonates with NEC and 39 "normal" neonates were collected to detect rotavirus (RV), astrovirus (ASV), sapovirus, enterovirus (EV), adenovirus (ADV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human bocavirus (HBoV). Rotavirus A (RVA), ASV, EBV, and ADV were detected in both the NEC and control groups; however, EV and HBoV were detected only in the NEC group and CMV was not detected in either group. ASV was the most common enteric virus, but no significant differences were found between NEC and control groups, as was similarly the case for EBV and EV. The prevalence of ADV and HBoV was higher in the NEC group than in the control group (P = 0.011, P = 0.005, respectively) but RVA showed the opposite trend (P = 0.014). Virus positivity or negativity had no influence on the clinical manifestation of NEC.Conclusion: The roles of different viruses in NEC are not congruent. Some, such as ASV, may be regarded as commensal in neonates, while in NEC patients, the presence of ADV and EBV may be related to severity of disease. What is known: • The etiology of NEC remains unknown. Studies on necrotizing enterocolitis (NEC) have not largely focused on enteric viruses and the conclusions were inconsistent. What is new: • Enteric viruses are common in the gut of neonates, but not all of them are pathogenic. • The existence of ADV and EBV may be related to the severity of NEC.

Antimicrobial-impregnated central venous catheters for preventing neonatal bloodstream infection: the PREVAIL RCT

BACKGROUND

Clinical trials show that antimicrobial-impregnated central venous catheters reduce catheter-related bloodstream infection in adults and children receiving intensive care, but there is insufficient evidence for use in newborn babies.

OBJECTIVES

The objectives were (1) to determine clinical effectiveness by conducting a randomised controlled trial comparing antimicrobial-impregnated peripherally inserted central venous catheters with standard peripherally inserted central venous catheters for reducing bloodstream or cerebrospinal fluid infections (referred to as bloodstream infections); (2) to conduct an economic evaluation of the costs, cost-effectiveness and value of conducting additional research; and (3) to conduct a generalisability analysis of trial findings to neonatal care in the NHS.

DESIGN

Three separate studies were undertaken, each addressing one of the three objectives. (1) This was a multicentre, open-label, pragmatic randomised controlled trial; (2) an analysis was undertaken of hospital care costs, lifetime cost-effectiveness and value of information from an NHS perspective; and (3) this was a retrospective cohort study of bloodstream infection rates in neonatal units in England.

SETTING

The randomised controlled trial was conducted in 18 neonatal intensive care units in England.

PARTICIPANTS

Participants were babies who required a peripherally inserted central venous catheter (of 1 French gauge in size).

INTERVENTIONS

The interventions were an antimicrobial-impregnated peripherally inserted central venous catheter (coated with rifampicin-miconazole) or a standard peripherally inserted central venous catheter, allocated randomly (1 : 1) using web randomisation.

MAIN OUTCOME MEASURE

Study 1 - time to first bloodstream infection, sampled between 24 hours after randomisation and 48 hours after peripherally inserted central venous catheter removal. Study 2 - cost-effectiveness of the antimicrobial-impregnated peripherally inserted central venous catheter compared with the standard peripherally inserted central venous catheters. Study 3 - risk-adjusted bloodstream rates in the trial compared with those in neonatal units in England. For study 3, the data used were as follows: (1) case report forms and linked death registrations; (2) case report forms and linked death registrations linked to administrative health records with 6-month follow-up; and (3) neonatal health records linked to infection surveillance data.

RESULTS

Study 1, clinical effectiveness - 861 babies were randomised (antimicrobial-impregnated peripherally inserted central venous catheter, n = 430; standard peripherally inserted central venous catheter, n = 431). Bloodstream infections occurred in 46 babies (10.7%) randomised to antimicrobial-impregnated peripherally inserted central venous catheters and in 44 (10.2%) babies randomised to standard peripherally inserted central venous catheters. No difference in time to bloodstream infection was detected (hazard ratio 1.11, 95% confidence interval 0.73 to 1.67; p = 0.63). Secondary outcomes of rifampicin resistance in positive blood/cerebrospinal fluid cultures, mortality, clinical outcomes at neonatal unit discharge and time to peripherally inserted central venous catheter removal were similar in both groups. Rifampicin resistance in positive peripherally inserted central venous catheter tip cultures was higher in the antimicrobial-impregnated peripherally inserted central venous catheter group (relative risk 3.51, 95% confidence interval 1.16 to 10.57; p = 0.02) than in the standard peripherally inserted central venous catheter group. Adverse events were similar in both groups. Study 2, economic evaluation - the mean cost of babies' hospital care was £83,473. Antimicrobial-impregnated peripherally inserted central venous catheters were not cost-effective. Given the increased price, compared with standard peripherally inserted central venous catheters, the minimum reduction in risk of bloodstream infection for antimicrobial-impregnated peripherally inserted central venous catheters to be cost-effective was 3% and 15% for babies born at 23-27 and 28-32 weeks' gestation, respectively. Study 3, generalisability analysis - risk-adjusted bloodstream infection rates per 1000 peripherally inserted central venous catheter days were similar among babies in the trial and in all neonatal units. Of all bloodstream infections in babies receiving intensive or high-dependency care in neonatal units, 46% occurred during peripherally inserted central venous catheter days.

LIMITATIONS

The trial was open label as antimicrobial-impregnated and standard peripherally inserted central venous catheters are different colours. There was insufficient power to determine differences in rifampicin resistance.

CONCLUSIONS

No evidence of benefit or harm was found of peripherally inserted central venous catheters impregnated with rifampicin-miconazole during neonatal care. Interventions with small effects on bloodstream infections could be cost-effective over a child's life course. Findings were generalisable to neonatal units in England. Future research should focus on other types of antimicrobial impregnation of peripherally inserted central venous catheters and alternative approaches for preventing bloodstream infections in neonatal care.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN81931394.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 57. See the NIHR Journals Library website for further project information.

Probiotic Supplementation During the Perinatal and Infant Period: Effects on Gut Dysbiosis and Disease

The perinatal period is crucial to the establishment of lifelong gut microbiota. The abundance and composition of microbiota can be altered by several factors such as preterm delivery, formula feeding, infections, antibiotic treatment, and lifestyle during pregnancy. Gut dysbiosis affects the development of innate and adaptive immune responses and resistance to pathogens, promoting atopic diseases, food sensitization, and infections such as necrotizing enterocolitis (NEC). Recent studies have indicated that the gut microbiota imbalance can be restored after a single or multi-strain probiotic supplementation, especially mixtures of Lactobacillus and Bifidobacterium strains. Following the systematic search methodology, the current review addresses the importance of probiotics as a preventive or therapeutic tool for dysbiosis produced during the perinatal and infant period. We also discuss the safety of the use of probiotics in pregnant women, preterm neonates, or infants for the treatment of atopic diseases and infections.

Probiotics' efficacy in paediatric diseases: which is the evidence? A critical review on behalf of the Italian Society of Pediatrics

During the last decade several paediatric studies have been published with different possible indications for probiotics, leading to a global increase of probiotics' market. Nevertheless, different study designs, multiple single/combined strains and small sample size still leave many uncertainties regarding their efficacy. In addition, different regulatory and quality control issues make still very difficult the interpretation of the clinical data. The objective of this review is to critically summarise the current evidence on probiotics' efficacy and safety on a different number of pathologies, including necrotizing enterocolitis, acute infectious diarrhoea, allergic diseases and functional gastrointestinal disorders in order to guide paediatric healthcare professionals on using evidence-based probiotics' strains. To identify relevant data, literature searches were performed including Medline-PubMed, the Cochrane Library and EMBASE databases. Considering probiotics strain-specific effects, the main focus was on individual probiotic strains and not on probiotics in general.

Meconium microbiota predicts clinical early-onset neonatal sepsis in preterm neonates

Background: Early-onset neonatal sepsis (EONS) remains one of the leading causes of morbidity and mortality related to premature birth, and its diagnosis remains difficult. Our goal was to evaluate the intestinal microbiota of the first meconium of preterm newborns and ascertain whether it is associated with clinical EONS.Methods: In a controlled, prospective cohort study, samples of the first meconium of premature infants with a gestational age (GA) ≤32 weeks was obtained at Hospital de Clínicas de Porto Alegre and DNA was isolated from the samples. 16S rDNA based microbiota composition of preterm infants with a clinical diagnosis of EONS was compared to that of a control group.Results: 40 (48%) premature infants with clinical diagnosis of EONS and 44 (52%) without EONS were included in the analysis. The most abundant phylum detected in both groups, Proteobacteria, was more prevalent in the sepsis group (p = .034). 14% of variance among bacterial communities (p = .001) correlated with EONS. The genera most strongly associated with EONS were Paenibacillus, Caulobacter, Dialister, Akkermansia, Phenylobacterium, Propionibacterium, Ruminococcus, Bradyrhizobium, and Alloprevotella. A single genus, Flavobacterium, was most strongly associated with the control group.Conclusion: These findings suggest that the first-meconium microbiota is different in preterm neonates with and without clinical EONS.

Cost-effectiveness of strategies preventing late-onset infection in preterm infants

OBJECTIVE

Developing a model to analyse the cost-effectiveness of interventions preventing late-onset infection (LOI) in preterm infants and applying it to the evaluation of anti-microbial impregnated peripherally inserted central catheters (AM-PICCs) compared with standard PICCs (S-PICCs).

DESIGN

Model-based cost-effectiveness analysis, using data from the Preventing infection using Antimicrobial Impregnated Long Lines (PREVAIL) randomised controlled trial linked to routine healthcare data, supplemented with published literature. The model assumes that LOI increases the risk of neurodevelopmental impairment (NDI).

SETTING

Neonatal intensive care units in the UK National Health Service (NHS).

PATIENTS

Infants born ≤32 weeks gestational age, requiring a 1 French gauge PICC.

INTERVENTIONS

AM-PICC and S-PICC.

MAIN OUTCOME MEASURES

Life expectancy, quality-adjusted life years (QALYs) and healthcare costs over the infants' expected lifetime.

RESULTS

Severe NDI reduces life expectancy by 14.79 (95% CI 4.43 to 26.68; undiscounted) years, 10.63 (95% CI 7.74 to 14.02; discounted) QALYs and costs £19 057 (95% CI £14 197; £24697; discounted) to the NHS. If LOI causes NDI, the maximum acquisition price of an intervention reducing LOI risk by 5% is £120. AM-PICCs increase costs (£54.85 (95% CI £25.95 to £89.12)) but have negligible impact on health outcomes (-0.01 (95% CI -0.09 to 0.04) QALYs), compared with S-PICCs. The NHS can invest up to £2.4 million in research to confirm that AM-PICCs are not cost-effective.

CONCLUSIONS

The model quantifies health losses and additional healthcare costs caused by NDI and LOI during neonatal care. Given these consequences, interventions preventing LOI, even by a small extent, can be cost-effective. AM-PICCs, being less effective and more costly than S-PICC, are not likely to be cost-effective.

TRIAL REGISTRATION NUMBER

NCT03260517.

Overexpressed FOXO3 improves inflammatory status in mice by affecting NLRP3-mediated cell coronation in necrotizing colitis mice

OBJECTIVE

To investigate the relationship between FOXO3 overexpression and NLRP3 and explore the effect of FOXO3 on necrotizing colitis.

METHODS

100 clean grade newborn SD (Sprague Dawley) rats were randomly divided into 4 groups: NEC group, NEC + FOXO3a group, NEC + NC group and control group. NEC rat model was established by hypoxia + hypothermia stimulation; HE staining was used for detection of the inflammation of intestinal tissue. The histological scores of intestinal tissues were histologically scored, generally, there were three types of inflammatory scoring systems including anatomically based systems, severity-based systems and quality of life systems (Lim et al., 2015) and in this study we utilized severity-based systems by HE staining. Human intestinal epithelial cell line was transfected with recombinant plasmid overexpressing FOXO3a and recombinant plasmid overexpressing NLRP3, and divided into control group, LPS group, LPS + NC group, LPS + FOXO3a group and LPS + FOXO3a + NLRP3 group; Caspase-1 was used for the detection of pyroptosis. The expressions of FOXO3a, NLRP3, cleaved Caspase-1 and the expression of TLR4 in TLR4 signaling pathway were detected by RT-qPCR and WB. IL-1β, IL-6, IL-18 and TNF-α were detected by ELISA.

RESULTS

(1) FOXO3a is under-expressed and NLRP3 is highly expressed in NEC neonatal rat intestinal tissue. (2) The inflammatory condition of intestinal tissue in NEC + FOXO3a group was improved compared with NEC group (P < 0.05). (3) FOXO3a was highly expressed in NEC + FOXO3a group. The expression of IL-1β, IL-6, IL-18, SOD and MDA in NEC + FOXO3a group was lower than that in NEC group. (4) The expression of IL-1β, IL-6, IL-18, SOD and MDA in intestinal epithelial cells of LPS + FOXO3a group was lower than other groups. (5) Overexpression of FOXO3a inhibits LPS-induced pyroptotic cell death in intestinal epithelial cells by inhibiting NLRP3.

CONCLUSION

Overexpression of FOXO3 in mice with necrotizing colitis can improve inflammatory conditions in mice by affecting NLRP3-mediated cell caking.

The impact of preterm adversity on cardiorespiratory function

NEW FINDINGS

What is the topic of this review? We review the influence of prematurity on the cardiorespiratory system and examine the common sequel of alterations in oxygen tension, and immune activation in preterm infants. What advances does it highlight? The review highlights neonatal animal models of intermittent hypoxia, hyperoxia and infection that contribute to our understanding of the effect of stress on neurodevelopment and cardiorespiratory homeostasis. We also focus on some of the important physiological pathways that have a modulatory role on the cardiorespiratory system in early life.

ABSTRACT

Preterm birth is one of the leading causes of neonatal mortality. Babies that survive early-life stress associated with immaturity have significant prevailing short- and long-term morbidities. Oxygen dysregulation in the first few days and weeks after birth is a primary concern as the cardiorespiratory system slowly adjusts to extrauterine life. Infants exposed to rapid alterations in oxygen tension, including exposures to hypoxia and hyperoxia, have altered redox balance and active immune signalling, leading to altered stress responses that impinge on neurodevelopment and cardiorespiratory homeostasis. In this review, we explore the clinical challenges posed by preterm birth, followed by an examination of the literature on animal models of oxygen dysregulation and immune activation in the context of early-life stress.

The role of the preterm intestinal microbiome in sepsis and necrotising enterocolitis

Late-onset sepsis (LOS) and necrotising enterocolitis (NEC) account for the highest number of deaths in premature infants and often cause severe morbidity in survivors. NEC is an inflammatory mediated condition, but its pathophysiology remains poorly understood. There is increasing evidence that in LOS the causative organism most often translocates from the gut. No causative microorganism has been consistently associated with either LOS or NEC, but an aberrant gut microbiome development could play a pivotal role. A low bacterial diversity and a delay in anaerobic bacteria colonization may predispose preterm infants to disease development. Conversely, a predominance of Bifidobacterium species and breast milk feeding might help to prevent disease onset. With numerous studies reporting conflicting results, further research is needed to better understand the role of microorganisms and type of feeding in the health status of preterm infants.

Mixed probiotics decrease the incidence of stage II-III necrotizing enterocolitis and death: A systematic review and meta-analysis

BACKGROUND

Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in premature infants. In order to evaluate the efficacy of probiotics in the prevention of stage II-III NEC, we performed a meta-analysis of clinical studies.

METHODS

We searched in PubMed, Medline and Embase from 1 January 1990 to 16 January 2018. Heterogeneity was examined by Q-test. Publication bias was evaluated by funnel plot and Egger's regression test.

RESULTS

30 articles were identified meeting the inclusion criteria. Data showed that probiotics supplement could significantly reduce the risk of stage II-III NEC (RR = 0.51, 95% CI, 0.38 to 0.67, P < 0.001) and death rate (RR = 0.69, 95% CI, 0.55 to 0.87, P = 0.002). The mixed probiotics and lactobacillus could reduce the risk of stage II-III NEC (for mixed probiotics, RR = 0.39, 95% CI, 0.26 to 0.57; for lactobacillus, RR = 0.53, 95% CI, 0.36 to 0.78), while bifidobacterium or saccharomyces did not have such effect. The results also indicated that only the mixed probiotics could reduce the risk of deaths (RR = 0.52, 95%CI, 0.34 to 0.80). Subgroup analysis for mortality revealed that probiotics had significant effect in Asian region (RR = 0.54, 95% CI, 0.37 to 0.80, P = 0.002) but not in non-Asian region (RR = 0.84, 95% CI, 0.66 to 1.08, P = 0.179).

CONCLUSIONS

Probiotics could significantly decrease the risk of stage II-III NEC and death. Compared to using single probiotics species, the application of combining different probiotics has a better efficacy in the prevention of stage II-III NEC and death, especially in the Asian population.

Bile acid abnormality induced by intestinal dysbiosis might explain lipid metabolism in Parkinson's disease

Intestinal dysbiosis refers to an imbalance in the intestinal flora. The concept of small intestinal bacterial overgrowth (SIBO), a condition of abnormal proliferation of the small intestine microbiota, has been proposed as a form of small intestine dysbiosis. In Parkinson's disease patients, weight loss and metabolic disorders such as lipid abnormalities are frequently encountered. This was a prospective investigation of the presence of SIBO using the lactulose breath test, Parkinson's disease symptoms, medications, abdominal symptoms, and blood data involving 39 Parkinson's disease patients. Of the 39 patients, 19 were positive for SIBO, 16 were negative, and 4 were equivocal. SIBO-positive patients had a significantly smaller dopaminergic drug load (dopamine replacement of Parkinson's disease drug potency) (P = 0.009) and significantly lower serum triglyceride (TG) (P = 0.024) and total bilirubin (P = 0.019) levels. No relationship was seen between the presence or absence of SIBO and motor or abdominal symptoms. The following hypothesis was developed with regard to the possibility that intestinal bacterial overgrowth has various effects that are exhibited via bile acid metabolism in Parkinson's disease patients. Serum bilirubin levels become higher as bilirubin metabolism declines with decreases in the intestinal bacteria. At the same time, bile acid is broken down due to increased intestinal bacteria, and lipid absorption decreases. This induces low serum TG levels and leads to weight loss. By a similar mechanism, there is less absorption of vitamin D as bile acid levels decrease, leading to osteoporosis and fractures. The possibility that some of the non-motor manifestations accompanying Parkinson's disease are caused by intestinal dysbiosis needs to be considered.

The protective effects of fecal microbiota transplantation in an experimental model of necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a serious disease that affects premature neonates, causing high mortality. In the search for new options of treatment it was investigated whether fecal microbiota transplantation (FMT) decreased the inflammatory response during NEC development in experimental model.

METHODS

Wistar rats were used and divided as follows: naïve, control (NEC induction), FMT-before (transplantation of microbiota before insult) and FMT-after (microbiota transplantation after insult). The microbiota transplantation was performed by administering a feces solution obtained from an adult donor rat. The induction of enterocolitis involves feeding by artificial formula, hypothermia, hypoxia and endotoxin administration. MPO activity, TNF-α, IL-1β and IL-6 levels, oxidative and nitrosative damage and the grade of intestinal mucosa lesion were analyzed.

RESULTS

The control group had a significant increase of inflammatory and oxidative parameters when compared to naive animals. Both FMT-before and after decreased all inflammatory and oxidative damage parameters when compared to control group. This was also true to the intestinal mucosa damage.

CONCLUSION

FMT administered just before or after NEC induction improved gut and systemic inflammation, and gut oxidative damage and intestinal injury.

[Structural features of intestinal flora in preterm rats with cognitive impairment: an analysis based on high-thorough sequencing]

OBJECTIVE

To study the structural features of intestinal flora in preterm rats with cognitive impairment and the association of the change in intestinal flora with cognitive impairment in preterm rats.

METHODS

Sprague-Dawley rats at 16-17 days of gestation were intraperitoneally injected with lipopolysaccharide for two consecutive days to establish a model of cognitive impairment, and the rats treated with intraperitoneally injected phosphate-buffered saline were established as the control group. Cesarean section was performed on day 21 of gestation, and preterm rats were randomly assigned to healthy maternal rats for feeding. The place navigation test in the Morris water maze was used to evaluate cognition on day 30 after birth. According to the result, the preterm rats were divided into cognitive impairment group with 21 rats and normal control group with 10 rats. Hematoxylin and eosin staining was used to observe pathological changes of the hippocampus, and fecal samples were collected for 16S rRNA sequencing and analysis. A principal component analysis (PCA) was performed for intestinal flora.

RESULTS

Compared with the normal control group, the cognitive impairment group showed degeneration and necrosis of a large number of neurons in the hippocampus. Compared with the normal control group, the cognitive impairment group had significant reductions in the abundance and diversity of intestinal flora (P<0.05), with a significant increase in the abundance of Proteobacteria at the phylum level (P<0.05), as well as significant reductions in the abundance of Prevotella and Lactobacillus and significant increases in the abundance of Staphylococcaceae and Oligella at the order, family, and genus levels (P<0.05). PCA showed a significant difference in the composition of intestinal flora between the two groups.

CONCLUSIONS

There is a significant change in the structure of intestinal flora in preterm rats with cognitive impairment, which provides a basis for the treatment and intervention of microecological changes due to cognitive impairment after preterm birth.

Challenge to the Intestinal Mucosa During Sepsis

Sepsis is a complex of life-threating organ dysfunction in critically ill patients, with a primary infectious cause or through secondary infection of damaged tissues. The systemic consequences of sepsis have been intensively examined and evidences of local alterations and repercussions in the intestinal mucosal compartment is gradually defining gut-associated changes during sepsis. In the present review, we focus on sepsis-induced dysfunction of the intestinal barrier, consisting of an increased permeability of the epithelial lining, which may facilitate bacterial translocation. We discuss disturbances in intestinal vascular tonus and perfusion and coagulopathies with respect to their proposed underlying molecular mechanisms. The consequences of enzymatic responses by pancreatic proteases, intestinal alkaline phosphatases, and several matrix metalloproteases are also described. We conclude our insight with a discussion on novel therapeutic interventions derived from crucial aspects of the gut mucosal dynamics during sepsis.

Probiotics for preterm infants: A National Retrospective Cohort Study

OBJECTIVE

To evaluate the effect of prophylactic probiotic (PP) administration on rates of necrotizing enterocolitis (NEC), late-onset sepsis (LOS), and mortality in preterm infants.

STUDY DESIGN

We conducted a retrospective cohort study of infants < 29 weeks' gestation, admitted to neonatal intensive care units participating in the Canadian Neonatal Network between 1 January 2014 and 31 December 2015. Infants in the exposure group received PP. A multiple logistic regression model with generalized estimation equation was used.

RESULTS

A total of 3093 infants were included, 652 infants (21%) received PP. The adjusted odds ratios (aOR) of NEC (aOR 0.64, 95% confidence interval [CI] 0.410, 0.996), mortality (aOR 0.41, 95% CI 0.26, 0.63), and a composite of NEC or mortality were significantly lower in the PP group. There was no significant difference in the aOR of LOS.

CONCLUSION

Prophylactic probiotic administration is associated with a reduction in NEC and mortality in preterm infants.

Changes of intestinal microbiota composition and diversity in very low birth weight infants related to strategies of NEC prophylaxis: protocol for an observational multicentre pilot study

Background

At the Division of Neonatology, Department of Paediatrics, Medical University Graz, a unique regimen of necrotizing enterocolitis (NEC) prophylaxis in preterm infants showing a < 1500 g birth weight (i.e. very low birth weight, VLBW) is used. The regimen includes oral antibiotic and antifungal therapy and probiotic preparations as well as a standardised feeding regimen. The incidence of NEC in preterm infants treated by this regimen has been shown to be lower, reflecting 0.7% when treatment was initiated on the first day of life, compared to international incidence rates (5.1%). However, the impact of the prophylaxis regimen on the intestinal microbiome is yet unknown.

Methods

We here report the protocol of an observational multicentre STROBE compliant pilot study in VLBW preterm infants. Research will compare three groups as defined by different NEC prophylaxis regimens. Each centre will provide 20 infants. Stool samples will be collected every 2 days throughout the first 2 weeks of life. Samples will be stored at − 80 °C until 16S-rRNA sequencing. 16S-rRNA genes will be amplified using suitable primers (specific for bacteria, fungi and archaea) and prepared for MiSeq Sequencing. Analyses will be performed using public analysis-pipelines, such as Mothur and Qiime, thus allowing an analysis of high-throughput community sequencing data. Abundance and composition changes in intestinal microbiota will be compared between the groups throughout the first 2 weeks of life.

Discussion

Different surroundings at the three participating study centres, including contacts to care takers and parents, as well as feeding or medication all might influence intestinal microbiota composition and abundance. In the planned sequel study, this should be kept in mind and a more standardised process ought to be established. However, the results obtained from the presented pilot study will display the burden of bias and help to establish a more strict protocol for the future.

Trial registration

Trial has been registered with the German Registry for Clinical Trials (registry ID DRKS00009290).

Electronic supplementary material

The online version of this article (10.1186/s40814-017-0195-y) contains supplementary material, which is available to authorized users.

Role of HIV exposure and infection in relation to neonatal GBS disease and rectovaginal GBS carriage: a systematic review and meta-analysis

Streptococcus agalactiae (GBS) is the leading cause worldwide of neonatal sepsis. We sought to assess to which extent HIV exposure of neonates is associated with GBS neonatal disease. Furthermore, we assessed to which extent HIV infection in women is associated with maternal rectovaginal GBS carriage, the single most important risk factor for GBS neonatal disease. We searched Pubmed, Embase, and Web of Science for studies assessing the association between neonatal GBS disease and HIV-status of the mother and studies that assessed the association between rectovaginal GBS colonization and HIV status in women. HIV-exposed uninfected neonates were more than twice as likely to have neonatal GBS disease compared to unexposed neonates. HIV-exposed neonates were not at increased risk for early-onset neonatal disease, but were 4.43 times more likely to have late-onset neonatal GBS disease. There was no significant association between HIV infection status and rectovaginal GBS carriage. Public health interventions preventing neonatal GBS disease are urgently needed for the increasing group of HIV-exposed neonates. A framework integrating and explaining our findings highlights opportunities for the clinical practice and global health policy to prevent disease. Well-designed studies should clarify the relation between HIV-status and GBS carriage.

Changes in the Gut Microbiota After Early Administration of Oral Synbiotics to Young Infants in India

OBJECTIVES

The authors examined the changes in the developing gut microbiota of Indian infants enrolled in a colonization study of an oral synbiotic (Lactobacillus plantarum and fructo-oligosaccharides) preparation.

METHODS

Frozen stool samples were available from a previously published clinical study of the synbiotic preparation administered daily for 7 days to full-term Indian infants delivered by C-section. 16S rRNA gene sequencing of fecal bacterial community-DNA was done in 11 infants sampled on day 7 and day 60 of life.

RESULTS

All infants showed changes in bacterial diversity with age. While Firmicutes and Proteobacteria were predominant in all, Actinobacteria and Bacteroidetes were initially low on day 7. In control infants, we observed a significant increase (P = 0.012) in the proportions of Actinobacteria on day 60. In the treated group, during the 60-day period, there was a 10-fold increase in Bacteroidetes, a somewhat smaller increase in Firmicutes, and a reduction in Proteobacteria. Compared to controls, treated infants were increasingly colonized by different Gram-positive genera including Enterococcus, Lactobacillus, and Bifidobacterium. Relatively less known taxa and some unassigned sequence reads added to enriched diversity observed in the treated group.

CONCLUSIONS

There was a high level of bacterial diversity among infants examined in the present study. Synbiotic treatment induced an increase in overall taxa and Gram-positive diversity, especially in the first week of life. Changes in the microbiota during early infancy should be used as a rationale for selecting probiotics in diverse clinical settings.

Longitudinal development of the gut microbiome and metabolome in preterm neonates with late onset sepsis and healthy controls

BACKGROUND

Late onset sepsis (LOS) in preterm infants is associated with considerable morbidity and mortality. While studies have implicated gut bacteria in the aetiology of the disease, functional analysis and mechanistic insights are generally lacking. We performed temporal bacterial (n = 613) and metabolomic (n = 63) profiling on extensively sampled stool from 7 infants with LOS and 28 matched healthy (no LOS or NEC) controls.

RESULTS

The bacteria isolated in diagnostic blood culture usually corresponded to the dominant bacterial genera in the gut microbiome. Longitudinal changes were monitored based on preterm gut community types (PGCTs), where control infants had an increased number of PGCTs compared to LOS infants (P = 0.011). PGCT 6, characterised by Bifidobacteria dominance, was only present in control infants. Metabolite profiles differed between LOS and control infants at diagnosis and 7 days later, but not 7 days prior to diagnosis. Bifidobacteria was positively correlated with control metabolites, including raffinose, sucrose, and acetic acid.

CONCLUSIONS

Using multi-omic analysis, we show that the gut microbiome is involved in the pathogenesis of LOS. While the causative agent of LOS varies, it is usually abundant in the gut. Bifidobacteria dominance was associated with control infants, and the presence of this organism may directly protect, or act as a marker for protection, against gut epithelial translocation. While the metabolomic data is preliminary, the findings support that gut development and protection in preterm infants is associated with increased in prebiotic oligosaccharides (e.g. raffinose) and the growth of beneficial bacteria (e.g. Bifidobacterium).

Mechanisms Affecting the Gut of Preterm Infants in Enteral Feeding Trials

Large randomized controlled trials (RCTs) in preterm infants offer unique opportunities for mechanistic evaluation of the risk factors leading to serious diseases, as well as the actions of interventions designed to prevent them. Necrotizing enterocolitis (NEC) a serious inflammatory gut condition and late-onset sepsis (LOS) are common feeding and nutrition-related problems that may cause death or serious long-term morbidity and are key outcomes in two current UK National Institutes for Health Research (NIHR) trials. Speed of increasing milk feeds trial (SIFT) randomized preterm infants to different rates of increases in milk feeds with a primary outcome of survival without disability at 2 years corrected age. Enteral lactoferrin in neonates (ELFIN) randomizes infants to supplemental enteral lactoferrin or placebo with a primary outcome of LOS. This is a protocol for the mechanisms affecting the gut of preterm infants in enteral feeding trials (MAGPIE) study and is funded by the UK NIHR Efficacy and Mechanistic Evaluation programme. MAGPIE will recruit ~480 preterm infants who were enrolled in SIFT or ELFIN. Participation in MAGPIE does not change the main trial protocols and uses non-invasive sampling of stool and urine, along with any residual resected gut tissue if infants required surgery. Trial interventions may involve effects on gut microbes, metabolites (e.g., short-chain fatty acids), and aspects of host immune function. Current hypotheses suggest that NEC and/or LOS are due to a dysregulated immune system in the context of gut dysbiosis, but mechanisms have not been systematically studied within large RCTs. Microbiomic analysis will use next-generation sequencing, and metabolites will be assessed by mass spectrometry to detect volatile organic and other compounds produced by microbes or the host. We will explore differences between disease cases and controls, as well as exploring the actions of trial interventions. Impacts of this research are multiple: translation of knowledge of mechanisms promoting gut health may explain outcomes or suggest alternate strategies to improve health. Results may identify new non-invasive diagnostic or monitoring techniques, preventative or treatment strategies for NEC or LOS, or provide data useful for risk stratification in future studies. Mechanistic evaluation might be especially informative where there are not clear effects on the primary outcome (ISRCTN 12554594).

Association between birth route and late-onset sepsis in very preterm neonates

OBJECTIVE

To evaluate the association between birth route and late-onset sepsis (LOS), and coagulase-negative Staphylococcal (CONS)-related LOS in preterm neonates.

STUDY DESIGN

In this observational study, data from 20,038 infants born between 22 and 32 weeks' gestation and admitted to Canadian neonatal intensive care units between 2010 and 2014 were analyzed retrospectively. The impact of birth route on LOS was assessed using univariate analysis and multiple logistic regression.

RESULTS

A total of 8218 neonates were born via vaginal route and 11,820 via cesarean section. Incidence rates of LOS for infants born vaginally and via a cesarean section were 13.1 and 13.2%, respectively, and there was no significant difference in odds of LOS between the groups (adjusted odds ratio (AOR): 0.99; 95% CI 0.87 to 1.12); however, the odds of CONS sepsis were higher in the cesarean group (AOR: 1.15; 95% CI: 1.01 to 1.32).

CONCLUSION

Birth route did not have an impact on LOS, but was associated with CONS-related LOS.

[Research progress of the application of probiotics in preterm infants]

The gastrointestinal structure, function and immunity of preterm infants are immature. Furthermore the gastrointestinal microbe colonization is abnormal. Therefore the preterm infants are prone to a variety of gastrointestinal diseases. Probiotics can regulate gastrointestinal microbe constitute, improve gastrointestinal barrier function, reduce gastrointestinal inflammation response and regulate the immunity. At present, it is used for the prevention of necrotizing enterocolitis, late-onset sepsis, and feeding intolerance. The safety and efficacy of probiotics for preterm infants are still controversial.

Probiotic Administration in Infants With Gastroschisis: A Pilot Randomized Placebo-Controlled Trial

OBJECTIVES

Infants with gastroschisis often require long periods of gastric suctioning and hospitalization. The impact of these interventions on the intestinal microbiota and attempts to alter the microbial community have not been studied. We sought to determine how the intestinal microbiota is influenced by the current treatment of gastroschisis and whether alteration of the intestinal microbiota with a probiotic microbe will influence length of hospitalization.

METHODS

We performed a randomized, placebo-controlled pilot study of administration of probiotic Bifidobacterium longum subsp. infantis in 24 infants with gastroschisis. The primary outcome was changes in the fecal microbiota, and the secondary outcome was length of hospital stay.

RESULTS

Administration of the probiotic or placebo was well tolerated, even during the period of gastric suctioning. The overall microbial communities were not significantly different between groups, although analysis of the final specimens by family demonstrated higher Bifidobacteriaceae, lower Clostridiaceae, and trends toward lower Enterobacteriaceae, Enterococcaceae, Staphylococcaceae, and Streptococcaceae in the probiotic group. Clinical outcomes, including length of hospital stay, did not differ between groups.

CONCLUSIONS

In this pilot study, there was significant in infants with gastroschisis that was partially attenuated by the administration of B longum subsp. infantis.

Gut Microbiome Developmental Patterns in Early Life of Preterm Infants: Impacts of Feeding and Gender

Gut microbiota plays a key role in multiple aspects of human health and disease, particularly in early life. Distortions of the gut microbiota have been found to correlate with fatal diseases in preterm infants, however, developmental patterns of gut microbiome and factors affecting the colonization progress in preterm infants remain unclear. The purpose of this prospective longitudinal study was to explore day-to-day gut microbiome patterns in preterm infants during their first 30 days of life in the neonatal intensive care unit (NICU) and investigate potential factors related to the development of the infant gut microbiome. A total of 378 stool samples were collected daily from 29 stable/healthy preterm infants. DNA extracted from stool was used to sequence the V4 region of the 16S rRNA gene region for community analysis. Operational taxonomic units (OTUs) and α-diversity of the community were determined using QIIME software. Proteobacteria was the most abundant phylum, accounting for 54.3% of the total reads. Result showed shift patterns of increasing Clostridium and Bacteroides, and decreasing Staphylococcus and Haemophilus over time during early life. Alpha-diversity significantly increased daily in preterm infants after birth and linear mixed-effects models showed that postnatal days, feeding types and gender were associated with the α-diversity, p< 0.05–0.01. Male infants were found to begin with a low α-diversity, whereas females tended to have a higher diversity shortly after birth. Female infants were more likely to have higher abundance of Clostridiates, and lower abundance of Enterobacteriales than males during early life. Infants fed mother’s own breastmilk (MBM) had a higher diversity of gut microbiome and significantly higher abundance in Clostridiales and Lactobacillales than infants fed non-MBM. Permanova also showed that bacterial compositions were different between males and females and between MBM and non-MBM feeding types. In conclusion, infant postnatal age, gender and feeding type significantly contribute to the dynamic development of the gut microbiome in preterm infants.

Stool bacterial load in preterm infants with necrotising enterocolitis

Resected gut tissue in necrotising enterocolitis (NEC) has a higher bacterial load than controls. Quantitative PCR was performed on longitudinal NEC and control stool samples (n=72). No significant difference in the total bacterial load was found between samples at diagnosis compared to controls or temporally within NEC.

An Immunological Perspective on Neonatal Sepsis

Despite concerted international efforts, mortality from neonatal infections remains unacceptably high in some areas of the world, particularly for premature infants. Recent developments in flow cytometry and next-generation sequencing technologies have led to major discoveries over the past few years, providing a more integrated understanding of the developing human immune system in the context of its microbial environment. We review these recent findings, focusing on how in human newborns incomplete maturation of the immune system before a full term of gestation impacts on their vulnerability to infection. We also discuss some of the clinical implications of this research in guiding the design of more-accurate age-adapted diagnostic and preventive strategies for neonatal sepsis.

Gut Microbiome and Kidney Disease in Pediatrics: Does Connection Exist?

Child development is a unique and continuous process that is impacted by genetics and environmental factors. Gut microbiome changes with development and depends on the stage of gut maturation, nutrition, and overall health. In spite of emerging data and active study in adults, the gut-renal axis in pediatrics has not been well considered and investigated. This review will focus on the current knowledge of gut microbiota impacts on kidney disease with extrapolation to the pediatric population.

Epigenome-Microbiome crosstalk: A potential new paradigm influencing neonatal susceptibility to disease

Preterm birth is the leading cause of infant morbidity and mortality. Necrotizing enterocolitis (NEC) is an inflammatory bowel disease affecting primarily premature infants, which can be lethal. Microbial intestinal colonization may alter epigenetic signatures of the immature gut establishing inflammatory and barrier properties predisposing to the development of NEC. We hypothesize that a crosstalk exists between the epigenome of the host and the initial intestinal colonizing microbiota at critical neonatal stages. By exposing immature enterocytes to probiotic and pathogenic bacteria, we showed over 200 regions of differential DNA modification, which were specific for each exposure. Reciprocally, using a mouse model of prenatal exposure to dexamethasone we demonstrated that antenatal treatment with glucocorticoids alters the epigenome of the host. We investigated the effects on the expression profiles of genes associated with inflammatory responses and intestinal barrier by qPCR-based gene expression array and verified the DNA modification changes in 5 candidate genes by quantitative methylation specific PCR (qMSP). Importantly, by 16S RNA sequencing-based phylogenetic analysis of intestinal bacteria in mice at 2 weeks of life, we showed that epigenome changes conditioned early microbiota colonization leading to differential bacterial colonization at different taxonomic levels. Our findings support a novel conceptual framework in which epigenetic changes induced by intrauterine influences affect early microbial colonization and intestinal development, which may alter disease susceptibility.

Prevention of Necrotizing Enterocolitis Through Manipulation of the Intestinal Microbiota of the Premature Infant

PURPOSE

In spite of four decades of research, necrotizing enterocolitis (NEC) remains the most common gastrointestinal complication in premature infants with high mortality and long-term morbidity. The composition of the intestinal microbiota of the premature infant differs dramatically from that of the healthy term infant and appears to be an important risk factor for NEC.

METHODS

We review the evidence of an association between intestinal dysbiosis and NEC and summarize published English language clinical trials and cohort studies involving attempts to manipulate the intestinal microbiota in premature infants.

FINDINGS

Promising NEC prevention strategies that alter the intestinal microbiota include probiotics, prebiotics, synbiotics, lacteroferrin, and human milk feeding.

IMPLICATIONS

Shaping the intestinal microbiota of the premature infant through human milk feeding and dietary supplements decreases the risk of NEC. Further studies to identify the ideal microbial composition and the most effective combination of supplements are indicated.

NOD2 Loss-of-Function Mutations and Risks of Necrotizing Enterocolitis or Focal Intestinal Perforation in Very Low-birth-weight Infants

BACKGROUND

NOD2 loss-of-function mutations, that is, R702W [rs2066844], G908R [rs2066845], and Leu1007fsinsC [rs5743293], have been linked to inflammatory bowel diseases. It is yet unknown whether these variants are also associated with necrotizing enterocolitis (NEC) or focal intestinal perforation (FIP) in infants of very low birth weight (VLBW).

METHODS

To test this hypothesis, we genotyped 9082 VLBW infants with European ancestry enrolled in a prospective, population-based cohort study of the German Neonatal Network. We assessed the effect of the NOD2 gene variants on the risk for major morbidities of the gastrointestinal tract, that is, NEC/FIP requiring surgery in multivariable logistic regression analyses.

RESULTS

In the whole cohort of VLBW infants, carriers of ≥ 2 NOD2 variant alleles had an increased risk for NEC requiring surgery (odds ratio [OR], 3.57; 95% confidence interval [CI], 1.27-10.04; P = 0.03) and NEC or FIP requiring surgery (OR, 3.81; 95% CI, 1.70-8.51; P = 0.004) as compared with wild-type genotypes. In a multivariable logistic regression analysis including gestational age, birth weight, gender, multiple birth, and inborn delivery, the association between ≥ 2 NOD2 variant alleles and NEC surgery (OR, 4.14; 95% CI, 1.41-12.12; P = 0.009), FIP surgery (OR, 3.50; 95% CI, 1.02-12.04; P = 0.047), and NEC or FIP surgery (OR, 4.10; 95% CI, 1.74-9.73; P = 0.001) proved to be independent. We also performed a regression analysis in the subgroup of infants with available information on Lactobacillus acidophilus/Bifidobacterium infantis probiotic supplementation (n = 3638). Although probiotics had a protective effect on NEC and NEC or FIP requiring surgery, the NOD2 variants had no significant impact in this subgroup.

CONCLUSIONS

VLBW infants carrying ≥ 2 NOD2 genetic risk factors of inflammatory bowel disease in adults have an increased risk for severe gastrointestinal complications, such as NEC requiring surgery. Therefore, infants might benefit from NOD2 genotyping followed by supplementation with probiotics. Replication studies are needed along with genome-wide arrays to allow risk-adapted prevention and therapeutic strategies.

Gene expression profiling in necrotizing enterocolitis reveals pathways common to those reported in Crohn's disease

BACKGROUND

Necrotizing enterocolitis (NEC) is the most frequent life-threatening gastrointestinal disease experienced by premature infants in neonatal intensive care units. The challenge for neonatologists is to detect early clinical manifestations of NEC. One strategy would be to identify specific markers that could be used as early diagnostic tools to identify preterm infants most at risk of developing NEC or in the event of a diagnostic dilemma of suspected disease. As a first step in this direction, we sought to determine the specific gene expression profile of NEC.

METHODS

Deep sequencing (RNA-Seq) was used to establish the gene expression profiles in ileal samples obtained from preterm infants diagnosed with NEC and non-NEC conditions. Data were analyzed with Ingenuity Pathway Analysis and ToppCluster softwares.

RESULTS

Data analysis indicated that the most significant functional pathways over-represented in NEC neonates were associated with immune functions, such as altered T and B cell signaling, B cell development, and the role of pattern recognition receptors for bacteria and viruses. Among the genes that were strongly modulated in neonates with NEC, we observed a significant degree of similarity when compared with those reported in Crohn's disease, a chronic inflammatory bowel disease.

CONCLUSIONS

Gene expression profile analysis revealed a predominantly altered immune response in the intestine of NEC neonates. Moreover, comparative analysis between NEC and Crohn's disease gene expression repertoires revealed a surprisingly high degree of similarity between these two conditions suggesting a new avenue for identifying NEC biomarkers.

Routine Use of Probiotics in Preterm Infants: Longitudinal Impact on the Microbiome and Metabolome

BACKGROUND

Probiotics are live microbial supplements that colonize the gut and potentially exert health benefit to the host.

OBJECTIVES

We aimed to determine the impact of a probiotic (Infloran®: Lactobacillus acidophilus-NCIMB701748 and Bifidobacterium bifidum-ATCC15696) on the bacterial and metabolic function of the preterm gut while in the neonatal intensive care unit (NICU) and following discharge.

METHODS

Stool samples (n = 88) were collected before, during, and after probiotic intake from 7 patients, along with time-matched controls from 3 patients. Samples were also collected following discharge home from the NICU. Samples underwent bacterial profiling analysis by 16S rRNA gene sequencing and quantitative PCR (qPCR), as well as metabolomic profiling using liquid chromatography mass spectrometry.

RESULTS

Bacterial profiling showed greater Bifidobacterium (15.1%) and Lactobacillus (4.2%) during supplementation compared to the control group (4.0% and 0%, respectively). While Lactobacillus became reduced after the probiotic had been stopped, Bifidobacterium remained high following discharge, suggestive of successful colonisation. qPCR analysis showed a significant increase (p ≤ 0.01) in B. bifidum in infants who received probiotic treatment compared to controls, but no significant increase was observed for L. acidophilus (p = 0.153). Metabolite profiling showed clustering based on receiving probiotic or matched controls, with distinct metabolites associated with probiotic administration.

CONCLUSIONS

Probiotic species successfully colonise the preterm gut, reducing the relative abundance of potentially pathogenic bacteria, and effecting gut functioning. Bifidobacterium (but not Lactobacillus) colonised the gut in the long term, suggesting the possibility that therapeutically administered probiotics may continue to exert important functional effects on gut microbial communities in early infancy.

Preterm gut microbiota and metabolome following discharge from intensive care

The development of the preterm gut microbiome is important for immediate and longer-term health following birth. We aimed to determine if modifications to the preterm gut on the neonatal intensive care unit (NICU) impacted the gut microbiota and metabolome long-term. Stool samples were collected from 29 infants ages 1-3 years post discharge (PD) from a single NICU. Additional NICU samples were included from 14/29 infants. Being diagnosed with disease or receiving increased antibiotics while on the NICU did not significantly impact the microbiome PD. Significant decreases in common NICU organisms including K. oxytoca and E. faecalis and increases in common adult organisms including Akkermansia sp., Blautia sp., and Bacteroides sp. and significantly different Shannon diversity was shown between NICU and PD samples. The metabolome increased in complexity, but while PD samples had unique bacterial profiles we observed comparable metabolomic profiles. The preterm gut microbiome is able to develop complexity comparable to healthy term infants despite limited environmental exposures, high levels of antibiotic administration, and of the presence of serious disease. Further work is needed to establish the direct effect of weaning as a key event in promoting future gut health.

Application of Laser Capture Microdissection and 16S rRNA Gene Polymerase Chain Reaction in the Analysis of Bacteria Colonizing the Intestinal Tissue of Neonates With Necrotizing Enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in newborns. However, the pathogenesis of NEC remains unclear because most bacterial characterizations of alleged pathogens have been performed via the analysis of human fecal samples and experimental animal studies. The objective is to investigate the microbial composition of NEC using inflamed intestinal tissue surgically removed from neonates diagnosed with NEC (n = 18).

METHODS

We obtained intestinal tissues via a combination of laser capture microdissection and Gram staining, which was used to mark individual bacteria. Tissues with congenital intestinal atresia (n = 7) served as control specimens. An analysis of the 16S rRNA of each sample was performed via polymerase chain reaction-denaturing gradient gel electrophoresis.

RESULTS

Numerous bacteria were observed in the inflamed intestinal wall tissue samples obtained from neonates with NEC following Gram staining and examination under an optical microscope. The total number of types detected by polymerase chain reaction-denaturing gradient gel electrophoresis was 12.17 ± 2.83 per infant with NEC, whereas only 2.57 ± 1.81 types were detected in each infant with congenital intestinal atresia. Proteobacteria had the highest constituent ratio (188 of 285) of all detected clone sequences in the NEC group. Additionally, Pseudomonas sp., Acinetobacter sp., Klebsiella sp., Clostridium sp., Ochrobactrum sp. and Arcobacter sp. were detected only in the NEC group.

CONCLUSIONS

The combination of Gram staining and laser capture microdissection was a reliable method to obtain and prepare tissue samples for processing. NEC was associated with multiple species of bacteria, and microflora within the disease-affected sites may be relatively specific and stable. Proteobacteria demonstrated the highest constituent ratio. Our observations warrant closer examination of the 6 bacterial genera that were only detected in NEC, particularly Clostridium sp., which may be closely correlated with pneumatosis intestinalis.

Early Life Experience and Gut Microbiome: The Brain-Gut-Microbiota Signaling System

BACKGROUND

Over the past decades, advances in neonatal care have led to substantial increases in survival among preterm infants. With these gains, recent concerns have focused on increases in neurodevelopment morbidity related to the interplay between stressful early life experiences and the immature neuroimmune systems. This interplay between these complex mechanisms is often described as the brain-gut signaling system. The role of the gut microbiome and the brain-gut signaling system have been found to be remarkably related to both short- and long-term stress and health. Recent evidence supports that microbial species, ligands, and/or products within the developing intestine play a key role in early programming of the central nervous system and regulation of the intestinal innate immunity.

PURPOSE

The purpose of this state-of-the-science review is to explore the supporting evidence demonstrating the importance of the brain-gut-microbiota axis in regulation of early life experience. We also discuss the role of gut microbiome in modulating stress and pain responses in high-risk infants. A conceptual framework has been developed to illustrate the regulation mechanisms involved in early life experience.

CONCLUSIONS

The science in this area is just beginning to be uncovered; having a fundamental understanding of these relationships will be important as new discoveries continue to change our thinking, leading potentially to changes in practice and targeted interventions.