Sensitive Quantitative Analysis of the Meconium Bacterial Microbiota in Healthy Term Infants Born Vaginally or by Cesarean Section

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Reviewed Marked as Reviewed by Shaimaa Elsafoury on 2021/02/09
PMID PubMed identifier for scientific articles.
DOI Digital object identifier for electronic documents.
Nagpal R, Tsuji H, Takahashi T, Kawashima K, Nagata S, Nomoto K, Yamashiro Y
Frontiers in microbiology
C-section, Lactobacillus, RT-qPCR, dysbiosis, gut bacteria, intestinal microbiota, meconium
For decades, babies were thought to be born germ-free, but recent evidences suggest that they are already exposed to various bacteria in utero. However, the data on population levels of such pioneer gut bacteria, particularly in context to birth mode, is sparse. We herein aimed to quantify such bacteria from the meconium of 151 healthy term Japanese infants born vaginally or by C-section. Neonatal first meconium was obtained within 24-48 h of delivery; RNA was extracted and subjected to reverse-transcription-quantitative PCR using specific primers for Clostridium coccoides group, C. leptum subgroup, Bacteroides fragilis group, Atopobium cluster, Prevotella, Bifidobacterium, Lactobacillus, Enterococcus, Enterobacteriaceae, Staphylococcus, Enterococcus, Streptococcus, C. perfringens, and C. difficile. We detected several bacterial groups in both vaginally- and cesarean-born infants. B. fragilis group, Enterobacteriaceae, Enterococcus, Streptococcus, and Staphylococcus were detected in more than 50% of infants, with counts ranging from 105 to 108 cells/g sample. About 30-35% samples harbored Bifidobacterium and Lactobacillus (104-105 cells/g); whereas C. coccoides group, C. leptum subgroup and C. perfringens were detected in 10-20% infants (103-105 cells/g). Compared to vaginally-born babies, cesarean-born babies were significantly less often colonized with Lactobacillus genus (6% vs. 37%; P = 0.01) and Lactobacillus gasseri subgroup (6% vs. 31%; P = 0.04). Overall, seven Lactobacillus subgroups/species, i.e., L. gasseri subgroup, L. ruminis subgroup, L. casei subgroup, L. reuteri subgroup, L. sakei subgroup, L. plantarum subgroup, and L. brevis were detected in the samples from vaginally-born group, whereas only two members, i.e., L. gasseri subgroup and L. brevis were detected in the cesarean group. These data corroborate that several bacterial clades may already be present before birth in term infants' gut. Further, lower detection rate of lactobacilli in cesarean-born babies suggests that the primary source of lactobacilli in infant gut is mainly from maternal vaginal and-to a lesser extent-anal microbiota during vaginal delivery, and that the colonization by some important Lactobacillus species is delayed in babies delivered via cesarean-section.

Experiment 1

Reviewed Marked as Reviewed by Shaimaa Elsafoury on 2021/02/09

Curated date: 2021/01/10

Curator: WikiWorks

Revision editor(s): Shaimaa, WikiWorks


Location of subjects
Host species Species from which microbiome was sampled. Contact us to have more species added.
Homo sapiens
Body site Anatomical site where microbial samples were extracted from according to the Uber Anatomy Ontology
Meconium Meconium,meconium
Condition The experimental condition / phenotype studied according to the Experimental Factor Ontology
Cesarean section caesarean section,Cesarean section,cesarean section
Group 0 name Corresponds to the control (unexposed) group for case-control studies
vaginal delivery
Group 1 name Corresponds to the case (exposed) group for case-control studies
Group 0 sample size Number of subjects in the control (unexposed) group
Group 1 sample size Number of subjects in the case (exposed) group
Antibiotics exclusion Number of days without antibiotics usage (if applicable) and other antibiotics-related criteria used to exclude participants (if any)
No information about pre-delivey duration. 3 Vaginally-delivered infants have been exposed to antibiotics (birth to sampling)

Lab analysis

Sequencing type
16S variable region One or more hypervariable region(s) of the bacterial 16S gene
Not specified
Sequencing platform Manufacturer and experimental platform used for quantifying microbial abundance

Statistical Analysis

Statistical test
Fisher's Exact Test
Significance threshold p-value or FDR threshold used for differential abundance testing (if any)
MHT correction Have statistical tests be corrected for multiple hypothesis testing (MHT)?

Signature 1

Reviewed Marked as Reviewed by Shaimaa Elsafoury on 2021/02/09

Curated date: 2021/01/10

Curator: Shaimaa Elsafoury

Revision editor(s): WikiWorks

Source: Table 2 & Figure 2

Description: Count and detection rate of bacterial groups in meconium of vaginally and ceasarean born babies

Abundance in Group 1: decreased abundance in C-section

NCBI Quality ControlLinks
Lactobacillus gasseri

Revision editor(s): WikiWorks