First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota.

<h4>Background</h4>Considerable effort has been made to categorise the bacterial composition of the human gut and correlate findings with gastrointestinal disease. The infant gut has long been considered sterile at birth followed by rapid colonisation; however, this view has recently bee...

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Main Authors: Richard Hansen, Karen P Scott, Shoaib Khan, Jenny C Martin, Susan H Berry, Matthew Stevenson, Augusta Okpapi, Michael J Munro, Georgina L Hold
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2015-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0133320
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author Richard Hansen
Karen P Scott
Shoaib Khan
Jenny C Martin
Susan H Berry
Matthew Stevenson
Augusta Okpapi
Michael J Munro
Georgina L Hold
author_facet Richard Hansen
Karen P Scott
Shoaib Khan
Jenny C Martin
Susan H Berry
Matthew Stevenson
Augusta Okpapi
Michael J Munro
Georgina L Hold
author_sort Richard Hansen
collection DOAJ
description <h4>Background</h4>Considerable effort has been made to categorise the bacterial composition of the human gut and correlate findings with gastrointestinal disease. The infant gut has long been considered sterile at birth followed by rapid colonisation; however, this view has recently been challenged. We examined first-pass meconium from healthy term infants to confirm or refute sterility.<h4>Methods</h4>Healthy mothers were approached following vaginal delivery. First-pass meconium stools within 24 hours of delivery were obtained from healthy, breastfed infants with tight inclusion/exclusion criteria including rejecting any known antibiotic exposure - mother within 7 days preceding delivery or infant after birth. Stools were processed in triplicate for fluorescent in-situ hybridisation (FISH) with 16S rRNA-targeted probes including Bifidobacterium; Bacteroides-Prevotella; Lactobacillaceae/Enterococcaceae; Enterobacteriaceae; Streptococcaceae; Staphylococcaceae and Enterococcaceae. Absolute counts of all bacteria and proportional identification of each bacterial group were calculated. Confirmation of bacterial presence by PCR was undertaken on FISH-positive samples.<h4>Results</h4>The mothers of 31 newborn infants were recruited, 15 met inclusion/exclusion criteria and provided a sample within 24 hours of birth, processed in the lab within 4 hours. All babies were 37-40 weeks gestation. 8/15 were male, mean birth weight was 3.4 kg and mean maternal age was 32 years. Meconium samples from 10/15 (66%) infants had evidence of bacteria based on FISH analysis. Of these, PCR was positive in only 1. Positive FISH counts ranged from 2.2-41.8 x 10(4) cells/g with a mean of 15.4 x 10(4) cells/g. (The limit of detection for automated counting is 10(6) cells/g). Cell counts were too low to allow formal diversity analysis. Amplification by PCR was not possible despite positive spiked samples demonstrating the feasibility of reaction. One baby was dominated by Enterobacteriaceae. The others contained 2-5 genera, with Bifidobacterium, Enterobacteriaceae, Enterococcaceae and Bacteroides-Prevotella the most prevalent. There was no association between bacterial counts and rupture of membrane duration, time to passage of meconium or time to lab.<h4>Conclusion</h4>This study provides evidence that low numbers of bacteria are present in first-pass meconium samples from healthy, vaginally-delivered, breastfed term infants. Only two-thirds of meconium samples had detectable bacteria, though at levels too low for automated counting or for reliable confirmation by PCR. This study suggests that gut bacterial colonisation is extremely limited at birth and occurs rapidly thereafter.
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spelling doaj.art-8fe423a50a5a44d6965f954f6c9f55f62022-12-21T20:37:31ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-01107e013332010.1371/journal.pone.0133320First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota.Richard HansenKaren P ScottShoaib KhanJenny C MartinSusan H BerryMatthew StevensonAugusta OkpapiMichael J MunroGeorgina L Hold<h4>Background</h4>Considerable effort has been made to categorise the bacterial composition of the human gut and correlate findings with gastrointestinal disease. The infant gut has long been considered sterile at birth followed by rapid colonisation; however, this view has recently been challenged. We examined first-pass meconium from healthy term infants to confirm or refute sterility.<h4>Methods</h4>Healthy mothers were approached following vaginal delivery. First-pass meconium stools within 24 hours of delivery were obtained from healthy, breastfed infants with tight inclusion/exclusion criteria including rejecting any known antibiotic exposure - mother within 7 days preceding delivery or infant after birth. Stools were processed in triplicate for fluorescent in-situ hybridisation (FISH) with 16S rRNA-targeted probes including Bifidobacterium; Bacteroides-Prevotella; Lactobacillaceae/Enterococcaceae; Enterobacteriaceae; Streptococcaceae; Staphylococcaceae and Enterococcaceae. Absolute counts of all bacteria and proportional identification of each bacterial group were calculated. Confirmation of bacterial presence by PCR was undertaken on FISH-positive samples.<h4>Results</h4>The mothers of 31 newborn infants were recruited, 15 met inclusion/exclusion criteria and provided a sample within 24 hours of birth, processed in the lab within 4 hours. All babies were 37-40 weeks gestation. 8/15 were male, mean birth weight was 3.4 kg and mean maternal age was 32 years. Meconium samples from 10/15 (66%) infants had evidence of bacteria based on FISH analysis. Of these, PCR was positive in only 1. Positive FISH counts ranged from 2.2-41.8 x 10(4) cells/g with a mean of 15.4 x 10(4) cells/g. (The limit of detection for automated counting is 10(6) cells/g). Cell counts were too low to allow formal diversity analysis. Amplification by PCR was not possible despite positive spiked samples demonstrating the feasibility of reaction. One baby was dominated by Enterobacteriaceae. The others contained 2-5 genera, with Bifidobacterium, Enterobacteriaceae, Enterococcaceae and Bacteroides-Prevotella the most prevalent. There was no association between bacterial counts and rupture of membrane duration, time to passage of meconium or time to lab.<h4>Conclusion</h4>This study provides evidence that low numbers of bacteria are present in first-pass meconium samples from healthy, vaginally-delivered, breastfed term infants. Only two-thirds of meconium samples had detectable bacteria, though at levels too low for automated counting or for reliable confirmation by PCR. This study suggests that gut bacterial colonisation is extremely limited at birth and occurs rapidly thereafter.https://doi.org/10.1371/journal.pone.0133320
spellingShingle Richard Hansen
Karen P Scott
Shoaib Khan
Jenny C Martin
Susan H Berry
Matthew Stevenson
Augusta Okpapi
Michael J Munro
Georgina L Hold
First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota.
PLoS ONE
title First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota.
title_full First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota.
title_fullStr First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota.
title_full_unstemmed First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota.
title_short First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota.
title_sort first pass meconium samples from healthy term vaginally delivered neonates an analysis of the microbiota
url https://doi.org/10.1371/journal.pone.0133320
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