Influence of own mother's milk and different proportions of formula on intestinal microbiota of very preterm newborns

Maternal-fetal-neonatal microbiome and outcomes associated with prematurity

Our understanding of the premature gut microbiome has increased rapidly in recent years. However, to advance this important topic we must further explore various aspects of the maternal microbiome, neonatal microbiota, and the opportunities for microbiome modulation. We invite authors to contribute research and clinical papers to the Collection "Maternal-fetal-neonatal microbiome and outcomes associated with prematurity".

The Association of Different Proportions of Human Milk of the Total Enteral Intake on Health Outcomes in Preterm Infants: A Systematic Review

Background: Human milk (HM) is a proven optimal food for preterm infants. However, there is uncertainty regarding the effects of different proportions of HM of the total enteral intake on health outcomes in preterm infants. Therefore, we conducted a systematic review of studies examining the effects of different proportions of HM of the total enteral intake on health outcomes in preterm infants. Methods: We conducted a literature search in the Web of Science, PubMed, and Scopus databases. The methodological quality of the included articles and the certainty of evidence were assessed according to the Newcastle-Ottawa Scale and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool, respectively. Results: Twelve studies were included in the review. Among the clinical findings, the effect of different proportions of HM of the total enteral feeding on health outcomes in preterm infants was divided into six primary outcomes: physical growth, length of stay, morbidity of any disease, all-cause mortality, feeding-related outcomes, and other health outcomes. The studies presented a high risk of bias for most of the domains. The certainty of the evidence was considered low or very low. Conclusions: The findings reiterated that greater proportions of HM positively affect the health outcomes of preterm infants. Overall, when the HM accounts for at least 20% of the total enteral intake, it has an effect on health outcomes in preterm infants. If the proportion of HM reaches 50%, the incidence and severity of necrotizing enterocolitis, as well as the time to reach enteral feeds, will be reduced. Increasing the proportion of HM in enteral feeding should be considered a priority in the feeding strategy for preterm infants in clinical practice.

Noninvasive Fecal Cytokine and Microbiota Profiles Predict Commencement of Necrotizing Enterocolitis in a Proof-of-Concept Study

Background and Aims

Necrotizing enterocolitis (NEC) is a life-threatening disease and the most common gastrointestinal emergency in premature infants. Accurate early diagnosis is challenging. Modified Bell's staging is routinely used to guide diagnosis, but early diagnostic signs are nonspecific, potentially leading to unobserved disease progression, which is problematic given the often rapid deterioration observed. We investigated fecal cytokine levels, coupled with gut microbiota profiles, as a noninvasive method to discover specific NEC-associated signatures that can be applied as potential diagnostic markers.

Methods

Premature babies born below 32 weeks of gestation were admitted to the 2-site neonatal intensive care unit (NICU) of Imperial College hospitals (St. Mary's or Queen Charlotte's & Chelsea) between January 2011 and December 2012. During the NICU stay, expert neonatologists grouped individuals by modified Bell's staging (healthy, NEC1, NEC2/3) and fecal samples from diapers were collected consecutively. Microbiota profiles were assessed by 16S rRNA gene amplicon sequencing and cytokine concentrations were measured by V-Plex multiplex assays.

Results

Early evaluation of microbiota profiles revealed only minor differences. However, at later time points, significant changes in microbiota composition were observed for Bacillota (adj. P = .0396), with Enterococcus being the least abundant in Bell stage 2/3 NEC. Evaluation of fecal cytokine levels revealed significantly higher concentrations of IL-1α (P = .045), IL-5 (P = .0074), and IL-10 (P = .032) in Bell stage 1 NEC compared to healthy individuals.

Conclusion

Differences in certain fecal cytokine profiles in patients with NEC indicate their potential use as diagnostic biomarkers to facilitate earlier diagnosis. Additionally, associations between microbial and cytokine profiles contribute to improving knowledge about NEC pathogenesis.

Source of human milk (mother or donor) is more important than fortifier type (human or bovine) in shaping the preterm infant microbiome

Milk fortifiers help meet the nutritional needs of preterm infants receiving their mother's own milk (MOM) or donor human milk. We conducted a randomized clinical trial (NCT03214822) in 30 very low birth weight premature neonates comparing bovine-derived human milk fortifier (BHMF) versus human-derived fortifier (H2MF). We found that fortifier type does not affect the overall microbiome, although H2MF infants were less often colonized by an unclassified member of Clostridiales Family XI. Secondary analyses show that MOM intake is strongly associated with weight gain and microbiota composition, including Bifidobacterium, Veillonella, and Propionibacterium enrichment. Finally, we show that while oxidative stress (urinary F2-isoprostanes) is not affected by fortifier type or MOM intake, fecal calprotectin is higher in H2MF infants and lower in those consuming more MOM. Overall, the source of human milk (mother versus donor) appears more important than the type of milk fortifier (human versus bovine) in shaping preterm infant gut microbiota.

Accuracy of clinical indicators of the nursing diagnosis of dysfunctional gastrointestinal motility in infants

This study aimed to analyze the accuracy of the clinical indicators of the nursing diagnosis of dysfunctional gastrointestinal motility in infants from neonatal units and identify their association with clinical variables. This is a study of the diagnostic accuracy of clinical indicators of the diagnosis of dysfunctional gastrointestinal motility, with a cross-sectional design, performed on 228 hospitalized infants in neonatal units. A high prevalence of dysfunctional gastrointestinal motility was identified in the studied population. Regarding accuracy measures, clinical indicators such as increased gastric residual, changes in bowel sounds, bile-colored gastric residual, regurgitation, absence of flatus, and hard and formed stool were useful to discriminate between infants with and without dysfunctional gastrointestinal motility. The findings can help nurses during the diagnostic process, as they identify which defining characteristics can be used to confirm or rule out the probability of occurrence of the diagnosis.

Human milk nutrient fortifiers alter the developing gastrointestinal microbiota of very-low-birth-weight infants

Nutrient fortifiers are added to human milk to support the development of very-low-birth-weight infants. Currently, bovine-milk-based fortifiers (BMBFs) are predominantly administered, with increasing interest in adopting human-milk-based fortifiers (HMBFs). Although beneficial for growth, their effects on the gastrointestinal microbiota are unclear. This triple-blind, randomized clinical trial (NCT02137473) tested how nutrient-enriching human milk with HMBF versus BMBF affects the gastrointestinal microbiota of infants born < 1,250 g during hospitalization. HMBF-fed infants (n = 63, n = 269 stools) showed lower microbial diversity, altered microbial community structure, and changes in predicted microbial functions compared with BMBF-fed infants (n = 56, n = 239 stools). HMBF-fed infants had higher relative and normalized abundances of unclassified Enterobacteriaceae and lower abundances of Clostridium sensu stricto. Post hoc analyses identified dose-dependent relationships between individual feed components (volumes of mother's milk, donor milk, and fortifiers) and the microbiota. These results highlight how nutrient fortifiers impact the microbiota of very-low-birth-weight infants during a critical developmental window.

Increasing early exposure to mother's own milk in premature newborns

OBJECTIVE

Increase the proportion of ≤33 weeks newborns exposed to mother's own milk (MOM) oral care by 12 h of age by 20% over 2 years to support a healthier microbiome.

STUDY DESIGN

We implemented interventions to support early expression of colostrum and reliable delivery of resultant MOM to premature newborns. Statistical process control charts were used to track progress and provide feedback to staff. Proportions of newborns exposed to MOM by 12 h were compared relative to baseline.

RESULTS

There were 46, 66, and 46 newborns in the baseline, implementation, and sustainability periods, respectively. The primary outcome improved from 48% to 61% in the implementation period (relative change 1.27, 95% CI 0.89, 1.81, p = 0.2), to 69% in sustainability period (relative to baseline 1.45, 95% CI 1.02, 2.08, p = 0.03).

CONCLUSION

An interdisciplinary team-based, multicycle, quality improvement intervention resulted in increased rates of early exposure to MOM.

Emerging trends and focus of human gastrointestinal microbiome research from 2010-2021: a visualized study

BACKGROUND

The gastrointestinal microbiome is an important component of the human body and is closely related to human health and disease. This study describes the hotspots of the human gastrointestinal microbiome research and its evolution in the past decade, evaluates the scientific cooperation network, and finally predicts the field's future development trend using bibliometric analysis and a visualized study.

METHODS

We searched the original articles from January 2010 to February 2021 in the Scopus database using the term "gastrointestinal microbiome" and its synonyms. CiteSpace was used to construct country and author co-occurrence map; conduct journal, citation cocitation analysis, and reference co-citation knowledge map; and form a keywords co-occurrence map, a clustering knowledge map, timeline view of keywords, and burst term map.

RESULT

A total of 4444 documents published from January 2010 to February 2021 were analysed. In approximately the past decade, the number of articles on the human gastrointestinal microbiome has increased rapidly, and the research topics focus on different populations, research methods, and detection methods. All countries and regions in the world, led by the US, are studying the human gastrointestinal microbiome, and many research teams with close cooperation have been formed. The research has been published extensively in microbiology journals and clinical medicine journals, and the highly cited articles mainly describe the relationship between gastrointestinal microorganisms and human health and disease. Regarding the research emphasis, researchers' exploration of the human gastrointestinal microbiome (2011-2013) was at a relatively macro and superficial stage and sought to determine how the gastrointestinal microbiome relates to humans. From 2014 to 2017, increasingly more studies were conducted to determine the interaction between human gastrointestinal flora and various organs and systems. In addition, researchers (2018-2021) focused on the gastrointestinal microbial community and the diversity of certain types of microbes.

CONCLUSION

Over time, the scope of the research on the clinical uses of the gastrointestinal microbiome gradually increased, and the contents were gradually deepened and developed towards a more precise level. The study of the human gastrointestinal microbiome is an ongoing research hotspot and contributes to human health.

Early Enteral Feeding in Preterm Infants: A Narrative Review of the Nutritional, Metabolic, and Developmental Benefits

Enteral feeding is the preferred method of nutrient provision for preterm infants. Though parenteral nutrition remains an alternative to provide critical nutrition after preterm delivery, the literature suggests that enteral feeding still confers significant nutritional and non-nutritional benefits. Therefore, the purpose of this narrative review is to summarize health and clinical benefits of early enteral feeding within the first month of life in preterm infants. Likewise, this review also proposes methods to improve enteral delivery in clinical care, including a proposal for decision-making of initiation and advancement of enteral feeding. An extensive literature review assessed enteral studies in preterm infants with subsequent outcomes. The findings support the early initiation and advancement of enteral feeding impact preterm infant health by enhancing micronutrient delivery, promoting intestinal development and maturation, stimulating microbiome development, reducing inflammation, and enhancing brain growth and neurodevelopment. Clinicians must consider these short- and long-term implications when caring for preterm infants.

New Insights Into Microbiota Modulation-Based Nutritional Interventions for Neurodevelopmental Outcomes in Preterm Infants

Gut microbiota and the central nervous system have parallel developmental windows during pre and post-natal life. Increasing evidences suggest that intestinal dysbiosis in preterm infants predisposes the neonate to adverse neurological outcomes later in life. Understanding the link between gut microbiota colonization and brain development to tailor therapies aimed at optimizing initial colonization and microbiota development are promising strategies to warrant adequate brain development and enhance neurological outcomes in preterm infants. Breast-feeding has been associated with both adequate cognitive development and healthy microbiota in preterms. Infant formula are industrially produced substitutes for infant nutrition that do not completely recapitulate breast-feeding benefices and could be largely improved by the understanding of the role of breast milk components upon gut microbiota. In this review, we will first discuss the nutritional and bioactive component information on breast milk composition and its contribution to the assembly of the neonatal gut microbiota in preterms. We will then discuss the emerging pathways connecting the gut microbiota and brain development. Finally, we will discuss the promising microbiota modulation-based nutritional interventions (including probiotic and prebiotic supplementation of infant formula and maternal nutrition) for improving neurodevelopmental outcomes.

The Association Between Intestinal Bacteria and Allergic Diseases-Cause or Consequence?

The incidence of allergic disorders has been increasing over the past few decades, especially in industrialized countries. Allergies can affect people of any age. The pathogenesis of allergic diseases is complex and involves genetic, epigenetic, and environmental factors, and the response to medication is very variable. For some patients, avoidance is the sole effective therapy, and only when the triggers are identifiable. In recent years, the intestinal microbiota has emerged as a significant contributor to the development of allergic diseases. However, the precise mechanisms related to the effects of the microbiome on the pathogenesis of allergic diseases are unknown. This review summarizes the recent association between allergic disorders and intestinal bacterial dysbiosis, describes the function of gut microbes in allergic disease development from both preclinical and clinical studies, discusses the factors that influence gut microbial diversity and advanced techniques used in microbial analysis. Ultimately, more studies are required to define the host-microbial relationship relevant to allergic disorders and amenable to new therapeutic interventions.

The Effects of Genetic Relatedness on the Preterm Infant Gut Microbiota

The preterm infant gut microbiota is influenced by environmental, endogenous, maternal, and genetic factors. Although siblings share similar gut microbial composition, it is not known how genetic relatedness affects alpha diversity and specific taxa abundances in preterm infants. We analyzed the 16S rRNA gene content of stool samples, ≤ and >3 weeks postnatal age, and clinical data from preterm multiplets and singletons at two Neonatal Intensive Care Units (NICUs), Tampa General Hospital (TGH; FL, USA) and Carle Hospital (IL, USA). Weeks on bovine milk-based fortifier (BMF) and weight gain velocity were significant predictors of alpha diversity. Alpha diversity between siblings were significantly correlated, particularly at ≤3 weeks postnatal age and in the TGH NICU, after controlling for clinical factors. Siblings shared higher gut microbial composition similarity compared to unrelated individuals. After residualizing against clinical covariates, 30 common operational taxonomic units were correlated between siblings across time points. These belonged to the bacterial classes Actinobacteria, Bacilli, Bacteroidia, Clostridia, Erysipelotrichia, and Negativicutes. Besides the influence of BMF and weight variables on the gut microbial diversity, our study identified gut microbial similarities between siblings that suggest genetic or shared maternal and environmental effects on the preterm infant gut microbiota.

Mothers of Preterm Infants Have Individualized Breast Milk Microbiota that Changes Temporally Based on Maternal Characteristics

Mother's milk contains complex microbial communities thought to be important for colonizing a preterm infant's gastrointestinal tract. However, little is known about the microbiota in the preterm mother's milk and factors influencing its composition. We characterized the temporal dynamics of microbial communities in 490 breast milk samples from 86 mothers of preterm infants (born <1,250g) over the first 8 weeks postpartum. Highly individualized microbial communities were identified in each mother's milk that changed temporally with notable alterations in predicted microbial functions. However, pre-pregnancy BMI, delivery mode, and antibiotics were associated with changes in these microbial dynamics. Individual classes of antibiotics and their duration of exposure during prenatal and postpartum periods showed unique relationships with microbial taxa abundance and diversity in mother's milk. These results highlight the temporal complexity of the preterm mother's milk microbiota and its relationship with maternal characteristics as well as the importance of discussing antibiotic stewardship for mothers.

Differences in Compositions of Gut Bacterial Populations and Bacteriophages in 5-11 Year-Olds Born Preterm Compared to Full Term

Preterm infants are exposed to major perinatal, post-natal, and early infancy events that could impact on the gut microbiome. These events include infection, steroid and antibiotic exposure, parenteral nutrition, necrotizing enterocolitis, and stress. Studies have shown that there are differences in the gut microbiome during the early months of life in preterm infants. We hypothesized that differences in the gut microbial composition and metabolites in children born very preterm persist into mid-childhood. Participants were healthy prepubertal children aged 5-11 years who were born very preterm (≤32 weeks of gestation; n = 51) or at term (37-41 weeks; n = 50). We recorded the gestational age, birth weight, mode of feeding, mode of birth, age, sex, and the current height and weight of our cohort. We performed a multi'omics [i.e., 16S rRNA amplicon and shotgun metagenomic sequencing, SPME-GCMS (solid-phase microextraction followed by gas chromatography-mass spectrometry)] analysis to investigate the structure and function of the fecal microbiome (as a proxy of the gut microbiota) in our cross-sectional cohort. Children born very preterm were younger (7.8 vs. 8.3 years; p = 0.034), shorter [height-standard deviation score (SDS) 0.31 vs. 0.92; p = 0.0006) and leaner [BMI (body mass index) SDS -0.20 vs. 0.29; p < 0.0001] than the term group. Children born very preterm had higher fecal calprotectin levels, decreased fecal phage richness, lower plasma arginine, lower fecal branched-chain amino acids and higher fecal volatile (i.e., 3-methyl-butanoic acid, butyrolactone, butanoic acid and pentanoic acid) profiles. The bacterial microbiomes did not differ between preterm and term groups. We speculate that the observed very preterm-specific changes were established in early infancy and may impact on the capacity of the very preterm children to respond to environmental changes.

Breast Milk, a Source of Beneficial Microbes and Associated Benefits for Infant Health

Human breast milk is considered the optimum feeding regime for newborn infants due to its ability to provide complete nutrition and many bioactive health factors. Breast feeding is associated with improved infant health and immune development, less incidences of gastrointestinal disease and lower mortality rates than formula fed infants. As well as providing fundamental nutrients to the growing infant, breast milk is a source of commensal bacteria which further enhance infant health by preventing pathogen adhesion and promoting gut colonisation of beneficial microbes. While breast milk was initially considered a sterile fluid and microbes isolated were considered contaminants, it is now widely accepted that breast milk is home to its own unique microbiome. The origins of bacteria in breast milk have been subject to much debate, however, the possibility of an entero-mammary pathway allowing for transfer of microbes from maternal gut to the mammary gland is one potential pathway. Human milk derived strains can be regarded as potential probiotics; therefore, many studies have focused on isolating strains from milk for subsequent use in infant health and nutrition markets. This review aims to discuss mammary gland development in preparation for lactation as well as explore the microbial composition and origins of the human milk microbiota with a focus on probiotic development.

The challenges of neonatal sepsis management

OBJECTIVES

To present current evidence on the etiology, risk factors, diagnosis, and management of early and late neonatal sepsis.

SOURCE OF DATA

Non-systematic review of the Medline (PubMed), Scopus, Web of Science, Cochrane, and Google Scholar databases regarding the following terms: neonatal sepsis, early neonatal sepsis, late neonatal sepsis, empirical antibiotic therapy, sepsis calculator, vancomycin, newborn, preterm newborn.

DATA SYNTHESIS

Neonatal sepsis is a frequent cause of neonatal morbidity and mortality. Its diagnosis is difficult. Continuous observation of the patient is critical to diagnostic suspicion. When neonatal sepsis is suspected, bacteriological tests should be collected. Vancomycin should not be routinely using in the empirical antibiotic regimen in late neonatal sepsis, and the main protective mechanisms against neonatal sepsis are handwashing and the use of breast milk.

CONCLUSIONS

Newborns constitute a group that is more vulnerable to sepsis. Knowledge of risk factors and etiological agents allows a better approach to the newborn with sepsis.

Effect of Different Milk Diet on the Level of Fecal Calprotectin in Very Preterm Infants

Objective: To evaluate the course of fecal calprotectin (FC) in very preterm infants over the first 15 days of life in relation to the type of milk diet. Methods: This study was part of a randomized controlled trial comparing two different ways of integrating the own mother's milk (OMM) for the evaluation of feeding tolerance in very preterm infants. In infants with gestational age of ≤ 32 weeks randomized to receive preterm formula (PF group) or pasteurized donor human milk (PDHM group) as a supplement to the OMM insufficient or unavailable, FC level was planned to be measured at the first meconium passage and at days 8 and 15 of life (T0, T1, and T2, respectively). Results: FC data were available for all the 70 infants randomized, 35 in the PF group, and 35 in the PDHM group. The mean FC levels were similar in the two study groups at T0 and T1, whereas they were significantly higher in the PF group than the PDHM group at T2. FC values decreased over the first week of life in both groups and significantly increased over the second week of life only in the PF group. Conclusions: Our study demonstrates a significant increase in FC levels when PF is used as a supplement to the OMM compared to the use of PDHM. Further studies are needed to establish if the higher FC levels in infants receiving PF are the expression of a normal immunological maturation rather than an initial inflammatory process.