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Impact of Delivery Mode-Associated Gut Microbiota Dynamics on Health in the First Year of Life

Abstract

  • The early-life microbiome is affected by the mode of delivery.

  • This effect may depend on whether intrapartum antibiotics are administered to mothers.

  • The study assesses the effect of delivery mode on gut microbiota in 74 vaginally delivered and 46 Caesarean section (CS) infants, with routine antibiotic administration postponed until after cord clamping.

  • Key findings:

    • The microbiota differs between CS and vaginally delivered infants, with vaginal delivery showing an enrichment of Bifidobacterium spp. and reduction of Enterococcus and Klebsiella spp.

    • Microbiota composition at one week of life is associated with the number of respiratory infections (RIs) in the first year.

    • Taxa associated with increased RIs are more abundant in CS infants, suggesting a link between delivery mode and susceptibility to infections.

Introduction

  • Growing evidence of the human microbiome's impact on health regarding various immune disorders including allergies, obesity, inflammatory bowel disease.

  • The gastrointestinal (GI) tract hosts the majority and a diverse set of human commensal bacteria.

  • Early-life gut microbiota is crucial for immune system development during the “window of opportunity” (first 100 days of life).

Critical Influential Factors

  • Mode of Delivery:

    • Vaginal delivery associated with more favorable microbiota promoting immune development compared to CS, which can predispose to infections, allergies, inflammatory disorders.

  • Prevalence of CS Births:

    • Rising incidence, up to 40.5% in some countries.

  • Impact of Intrapartum Antibiotics:

    • Concerns regarding the effect of antibiotics on microbiota and health.

  • Breastfeeding Success:

    • Lower rates post-CS may lead to microbiota alterations.

Study Design

  • Participants:

    • 120 healthy children, 74 VD and 46 CS with no intrapartum antibiotic exposure (part of Microbiome Utrecht Infant Study [MUIS]).

    • Mothers received antibiotics only after cord clamping.

  • Sampling:

    • Comprehensive fecal samples collected from mothers and children over the first year.

    • Collection of clinical data including feeding type and antibiotic use.

Major Findings

Microbiota Composition Differences

  • VD infants demonstrated:

    • Evidence of fecal microbiota seeding from mothers.

    • More stable microbiota development.

    • Enrichment of beneficial taxa such as Bifidobacterium spp..

    • Significant reduction of harmful taxa such as Enterococcus and Klebsiella spp.

  • First Week of Life:

    • Most pronounced microbiota differences between delivery modes.

    • Composition linked to future respiratory infections.

Population Characteristics

  • Composition:

    • 74 vaginally delivered and 46 born by CS (36 planned, 10 emergency).

  • Clinical Variables:

    • Gestational age, duration of ruptured membranes, hospital stay, breastfeeding duration differed significantly between groups (p-values reported).

Microbiota Sampling and Sequencing Results

  • Sampling Data:

    • Out of 1243 fecal samples, 1139 (92%) met quality standards for analysis.

    • A total of 70,886,595 high-quality reads obtained.

    • Detection of 623 OTUs representative of 7 bacterial phyla with Firmicutes prevalent.

  • Bray-Curtis Dissimilarity Index:

    • Decreased over time, illustrating slow progression towards an adult-like microbiota.

    • Significant differences in compositional stability noted between VD and CS infants until the age of 2 months.

Fecal Microbiota Seeding

  • Concordance Studies:

    • VD infants' microbiota closely resembles that of their mothers, unlike CS infants, indicating a lack of direct maternal microbiota seeding.

Analysis of Gut Microbiota Dynamics

  • Bacterial Taxa Patterns:

    • Early taxa succession was influenced by delivery mode (highlighting genera like Escherichia, Staphylococcus, Bifidobacterium, Klebsiella).

    • Findings confirmed using post hoc analysis among exclusively formula-fed infants.

Impact on Health Outcomes

  • Respiratory Infections and Gut Microbiota:

    • Relationship observed between microbiota at 1 week and subsequent respiratory infections, emphasizing the importance of early microbiota composition in health.

  • Statistical Analyses and Findings:

    • Evidence supporting that early microbial presence is related to lower incidences of infections, specifically highlighting Bifidobacterium's role as beneficial and Klebsiella's role as pathogenic.

Conclusions

  • Mode of delivery significantly affects gut microbiota, especially within the first months.

  • Delayed colonization of beneficial bacteria (like Bifidobacterium) in CS born infants is critical for early life health.

  • Implications of altered microbiota composition extend to increased susceptibility to infections, underlining the importance of delivery method in shaping infant health outcomes.

Methods

  • Sample Population and Collection:

    • Recruitment of 120 full-term healthy infants, data collection throughout the first year.

  • DNA Isolation and Sequencing:

    • Detailed methodology of DNA extraction, sequencing, and bioinformatic processing, ensuring high quality of microbial community data.

Acknowledgments

  • Recognition of all participants, research staff, and funding sources.

Conflicts of Interest

  • Declaration of competing interests from authors involved in related fields.

References

  • Extensive citations regarding previous studies, methods utilized, and relevant literature supporting study findings.