Maternal antimicrobial use at delivery has a stronger impact than mode of delivery on bifidobacterial colonization in infants: a pilot study

Objective To investigate factors related to bifidobacterial colonization in early infancy, with a focus on maternal antimicrobial use at delivery. Study design A cross-sectional pilot study was performed. Feces samples of 33 Japanese healthy infants were collected over 10 months and analyzed by next-generation sequencing to examine the diversity and abundance of the gut microbiota. Results The beta diversity index of the gut microbiota differed significantly based on maternal antimicrobial use at delivery (P < 0.05). The most dominant genus was bifidobacteria, and the relative abundance of bifidobacteria in infants exposed to maternal antibiotics was significantly lower than in those who were not exposed (P < 0.05). In contrast, the delivery mode showed no significant relationship with gut microbiota diversity. Conclusions Maternal antimicrobial use at delivery has a stronger effect than delivery mode on the gut microbiota, especially for colonization of bifidobacteria.