The gut microbiome of extremely preterm infants randomized to the early progression of enteral feeding

Effect of early antibiotic exposure on necrotizing enterocolitis and growth in extremely preterm infants

BACKGROUND

The relationship between early antibiotic exposure, necrotizing enterocolitis (NEC), and growth faltering (GF) in extremely preterm infants is unknown.

METHODS

We evaluated the association between peripartum and postnatal antibiotic exposure in the first week after birth with NEC and GF in this secondary analysis of Preterm Erythropoietin Neuroprotection Trial subjects. NEC was defined as Bell's stage ≥ IIA; GF was defined as decreased weight, length, or head circumference (HC) z-score from birth to discharge of < -0.8. Multivariable analyses were adjusted with maternal and infant factors.

RESULTS

A total of 891 infants survived the first week and were included in the NEC analyses, while 828 infants survived to discharge and were included in the growth analyses. For every 1-day increase in infant antibiotic exposure during the first week after birth, there was a significantly increased adjusted hazard of NEC (aHR/day 1.14 [1.01-1.28], p = 0.034). Antibiotics for 3-4 days and 5-7 days total in the first week were associated with increased odds of weight GF (aOR 1.90 [1.21-2.99], aOR 2.32 [1.44-3.74]), length GF (aOR 1.76 [1.22-2.59], aOR 1.88 [1.26-2.80]), and HC GF (aOR 1.75 [1.08-2.84], aOR 1.87 [1.14-3.08]).

CONCLUSION

Increased antibiotic exposure in the first week after birth was associated with NEC and GF risk.

IMPACT

In this post-hoc analysis of a large multi-site trial, we found infant antibiotic exposure in the first week after birth was associated with an increased hazard of necrotizing enterocolitis in the extremely preterm infant after adjusting for maternal and infant factors. First week antibiotic exposure in the extremely preterm infant was associated with an increased odds of weight, linear, and head circumference growth faltering after adjusting for maternal and infant factors. These findings encourage the judicious use of early antibiotics in extremely preterm infants.

Early and exclusive enteral nutrition in infants born very preterm

OBJECTIVE

To characterise the effects of early and exclusive enteral nutrition with either maternal or donor milk in infants born very preterm (280/7-326/7 weeks of gestation).

DESIGN

Parallel-group, unmasked randomised controlled trial.

SETTING

Regional, tertiary neonatal intensive care unit.

PARTICIPANTS

102 infants born very preterm between 2021 and 2022 (51 in each group).

INTERVENTION

Infants randomised to the intervention group received 60-80 mL/kg/day within the first 36 hours after birth. Infants randomised to the control group received 20-30 mL/kg/day (standard trophic feeding volumes).

MAIN OUTCOME MEASURES

The primary outcome was the number of full enteral feeding days (>150 mL/kg/day) in the first 28 days after birth. Secondary outcomes included growth and body composition at the end of the first two postnatal weeks, and length of hospitalisation.

RESULTS

The mean birth weight was 1477 g (SD: 334). Half of the infants were male, and 44% were black. Early and exclusive enteral nutrition increased the number of full enteral feeding days (+2; 0-2 days; p=0.004), the fat-free mass-for-age z-scores at postnatal day 14 (+0.5; 0.1-1.0; p=0.02) and the length-for-age z-scores at the time of hospital discharge (+0.6; 0.2-1.0; p=0.002). Hospitalisation costs differed between groups (mean difference favouring the intervention group: -$28 754; -$647 to -$56 861; p=0.04).

CONCLUSIONS

In infants born very preterm, early and exclusive enteral nutrition increases the number of full enteral feeding days. This feeding practice may also improve fat-free mass accretion, increase length and reduce hospitalisation costs.

TRIAL REGISTRATION NUMBER

NCT04337710.

Gut microbiota in preterm infants receiving breast milk or mixed feeding

BACKGROUND

Preterm birth is the leading cause of mortality in newborns, with very-low-birth-weight infants usually experiencing several complications. Breast milk is considered the gold standard of nutrition, especially for preterm infants with delayed gut colonization, because it contains beneficial microorganisms, such as Lactobacilli and Bifidobacteria.

AIM

To analyze the gut microbiota of breastfed preterm infants with a birth weight of 1500 g or less.

METHODS

An observational study was performed on preterm infants with up to 36.6 wk of gestation and a birth weight of 1500 g or less, born at the University Hospital Dr. José Eleuterio González at Monterrey, Mexico. A total of 40 preterm neonates were classified into breast milk feeding (BM) and mixed feeding (MF) groups (21 in the BM group and 19 in the MF group), from October 2017 to June 2019. Fecal samples were collected before they were introduced to any feeding type. After full enteral feeding was achieved, the composition of the gut microbiota was analyzed using 16S rRNA gene sequencing. Numerical variables were compared using Student's t-test or using the Mann-Whitney U test for nonparametric variables. Dominance, evenness, equitability, Margalef's index, Fisher's alpha, Chao-1 index, and Shannon's diversity index were also calculated.

RESULTS

No significant differences were observed at the genus level between the groups. Class comparison indicated higher counts of Alphaproteobacteria and Betaproteobacteria in the initial compared to the final sample of the BM group (P < 0.011). In addition, higher counts of Gammaproteobacteria were detected in the final than in the initial sample (P = 0.040). According to the Margalef index, Fisher's alpha, and Chao-1 index, a decrease in species richness from the initial to the final sample, regardless of the feeding type, was observed (P < 0.050). The four predominant phyla were Bacteroidetes, Actinobacteria, Firmicutes, and Proteobacteria, with Proteobacteria being the most abundant. However, no significant differences were observed between the initial and final samples at the phylum level.

CONCLUSION

Breastfeeding is associated with a decrease in Alphaproteobacteria and Betaproteobacteria and an increase of Gammaproteobacteria, contributing to the literature of the gut microbiota structure of very low-birth-weight, preterm.

The Role of Diet and Nutritional Interventions for the Infant Gut Microbiome

The infant gut microbiome plays a key role in the healthy development of the human organism and appears to be influenced by dietary practices through multiple pathways. First, maternal diet during pregnancy and infant nutrition significantly influence the infant gut microbiota. Moreover, breastfeeding fosters the proliferation of beneficial bacteria, while formula feeding increases microbial diversity. The timing of introducing solid foods also influences gut microbiota composition. In preterm infants the gut microbiota development is influenced by multiple factors, including the time since birth and the intake of breast milk, and interventions such as probiotics and prebiotics supplementation show promising results in reducing morbidity and mortality in this population. These findings underscore the need for future research to understand the long-term health impacts of these interventions and for further strategies to enrich the gut microbiome of formula-fed and preterm infants.

Total Fluid Administration and Weight Loss during the First 2 Weeks in Infants Randomized to Early Enteral Feeding after Extremely Preterm Birth

BACKGROUND

Randomized trials have not reported the effects of the early progression of feeding volumes on fluid balance and neurodevelopment among infants born extremely preterm (≤28 weeks).

METHOD

Fluid, electrolyte, and neurodevelopment data of 60 extremely preterm infants randomly assigned to receive either 1 (early feeding group) or 4 days (late feeding group) of trophic feeding volumes at 20-24 mL/kg/day were analyzed.

RESULTS

Infants randomized to the early feeding group received less parenteral fluids, generated lower urine volumes, and had less excessive weight loss during the first 14 days after birth. The 7-point difference in cognitive scores and the 0.5 difference in weight-for-age z-scores favoring the early feeding group did not reach statistical significance.

CONCLUSIONS

In extremely preterm infants, early enteral feeding is associated with less total fluid administration and with less excessive weight loss during the first 2 weeks after birth. These short-term effects could have long-lasting benefits.

[Influence of enteral feeding initiation time on intestinal flora and metabolites in very low birth weight infants: a prospective study]

OBJECTIVES

To study the influence of enteral feeding initiation time on intestinal flora and metabolites in very low birth weight (VLBW) infants.

METHODS

A total of 29 VLBW infants who were admitted to the Department of Neonatology, Children's Hospital of Chongqing Medical University, from June to December, 2020, were enrolled as subjects. According to the enteral feeding initiation time after birth, the infants were divided into two groups: <24 hours (n=15) and 24-72 hours (n=14). Fecal samples were collected at weeks 2 and 4 of hospitalization, and 16S rDNA high-throughput sequencing and gas chromatography-mass spectrometry were used to analyze the microflora and short-chain fatty acids (SCFAs) respectively in fecal samples.

RESULTS

The analysis of microflora showed that there was no significant difference between the two groups in Chao index (reflecting the abundance of microflora) and Shannon index (reflecting the diversity of microflora) at weeks 2 and 4 after birth (P>0.05). The analysis of flora composition showed that there was no significant difference in the main microflora at the phylum and genus levels between the two groups at weeks 2 and 4 after birth (P>0.05). The comparison of SCFAs between the two groups showed that the <24 hours group had a significantly higher level of propionic acid than the 24-72 hours group at week 4 (P<0.05), while there was no significant difference in the total amount of SCFAs and the content of the other SCFAs between the two groups (P>0.05).

CONCLUSIONS

Early enteral feeding has no influence on the diversity and abundance of intestinal flora in VLBW infants, but enteral feeding within 24 hours can increase the level of propionic acid, a metabolite of intestinal flora.