Paper - Review

DOI: 10.1038/nm.4039

Abstract

Cesarean birthing
→ interrupt (exposure of newborns) → to the maternal vaginal microbiota

Babies (← delivered by C-section)
→ acquire a microbiota (← which differs from (vaginally delivered infants))
→ increased risk for (immune & metabolic disorders)

∴ Pilot study
→ Infants delivered by C-section → were exposed to maternal vaginal fluid at birth
→ these newborns was enriched in vaginal bacteria from 1⃣ the gut 2⃣ oral 3⃣ skin bacterial communities

Introduction

Mode of delivery
→ a major determinant (← of microbiota composition) (← of newborns)
1⃣ Vaginally delivered infants
→ harbor bacterial communities resembling those of the maternal vagina
2⃣ C-section delivered infants
→ are enriched in skin microbiota

Microbiome
→ have (a determinant role) (← in educating the immune system)
→ is essential → for (healthy immune development & metabolic programming)
→ is associated with (long-term effects) on (host metabolism & impaired immune development)

C-section delivery
→ increased risk of (obesity & asthma & allergies & immune deficiencies)

❗: exposed C-section delivered infants → to their maternal vaginal fluids
❓: determined (the composition of their microbiota) → whether it developed more similarly to (vaginally born babies)

Microbial restoration procedure
→ no signs of vaginosis
→ a vaginal pH < 4.5
→ within 2 minute of birth → exposed to their maternal vaginal contents

Microbiome composition
→ was characterized by sequencing the V4 of 16S rRNA gene
Bacterial source-tracking
← of the infant microbiome
→ resemble those of vaginally delivered infants

A progression
→ toward a body-specific configuration
→ either gradually (1⃣ anus) or quickly (1⃣ oral 2⃣ skin)

Confirmed the differences
← between unexposed & exposed C-section delivered infants
→ by building (a random forest classifier)

A random forest classifier
← built from predicted meta-genome content
→ to distinguish vaginally delivered and C-section delivered infants

Microbial colonization (← of body sites)
→ occurs quickly
→ changes proceed during the first month
→ Lactobacillus & Bacteroides →was NOT ❌ observed in newborn (← who were not exposed to vaginal fluids)

Infant (skin & oral) microbioata
→ more adult-like configuration
→ after the first week of life

Infant gut microbiome
→ occurs with the cessation of breast-feeding

Neonatal bacterial diversity
→ was highest at birth in (the anal & oral) sites
→ this declined by the third day

How similar (the microbiome of the gauzes)
→ were to (those of samples) obtained from the maternal body site at day 1
∵ C-section delivered infants were exposed → to vaginal fluids through the use of sterile gauzes

Bacterial community distance (← of each gauze sample)
→ to its own maternal vaginal samples was smaller than to those of other mothers
UniFrac distances (← from the gauzes) (→ to the vaginal samples)
→ were significantly smaller → than those the gauzes to the other body sites

Bacterial communities (← of newborns delivered by C-section)
→ can be partially restored to resemble
∵ compounded effects (← of the antibiotic treatments) (← which accompany the C-section procedure)

NO ❌ (apparent clustering) (← of the vaginal microbiota) on exposure to antibiotics
NO ❌ clear differences were observed (← in taxonomic composition)

Both (exposed & unexposed) C-section delivered infants
→ were comparable in term of (antibiotics exposure & feeding)

Partial microbial restoration
∵ infants are exposed a single time → to vaginal fluids

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