Birth method impacts infant gut microbiota colonization, diversity
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Infants born via caesarean section had lower total intestinal microbiota diversity and delayed Bacteroidetes colonization compared with children delivered vaginally in a recent study.
Researchers evaluated the intestinal microbiota in 24 healthy mothers and their infants, including 15 born vaginally and nine born via caesarean section (CS). Pyrosequencing of 16S rRNA genes was performed on stool samples collected from the mothers at 1 week after birth and from the infants at 1 week and 1, 3, 6, 12 and 24 months. Venous blood also was collected at 6, 12 and 24 months, and levels of Th1- and Th2-associated chemokines were assessed.
Maternal microbiota were typical of that observed among adults in previous studies and did not differ based on delivery method. While infant microbiota developed similarly at the phylum level between groups, total microbiota diversity was lower among infants in the CS group compared with vaginally delivered infants within the first year; the difference achieved statistical significance at 1 week, 3 months and 12 months. At the phylum level, delivery via CS was associated with lower diversity (P=.047).
Bacteroidetes phylum colonization occurred less frequently among infants delivered via CS at 1 week (11 cases vs. one; P=.005), 3 months (11 vs. one; P=.005) and 12 months (14 vs. four cases; P=.015). The CS group also had significantly less Bacteroidetes diversity at 1, 3, 12 and 24 months.
Levels of CXCL10 and CXCL11, both Th1-associated chemokines, were lower in the CS group (P=.05 for CXCL10; P=.008 for CXCL11). Th2-associated chemokine levels did not differ significantly between groups.
“CS-delivered infants who are not entering the birth canal of the mother either lacked or displayed a delayed colonization of one of the major gut phylum,” the researchers wrote. “Our study corroborates earlier studies reporting a delayed colonization of Bacteroides in babies delivered by CS. In addition, our study provides evidence that specific lineages of the intestinal microbiota, as defined by 16S rRNA gene sequences, are transmitted from mother to child during vaginal delivery.”
Disclosure: The researchers report no relevant financial disclosures.