Association Between Breast Milk Bacterial Communities and Establishment and Development of the Infant Gut Microbiome

Establishment of the infant microbiome has lifelong implications on health and immunity. Gut microbiota of breastfed compared with nonbreastfed individuals differ during infancy as well as into adulthood. Breast milk contains a diverse population of bacteria, but little is known about the vertical transfer of bacteria from mother to infant by breastfeeding.

To determine the association between the maternal breast milk and areolar skin and infant gut bacterial communities. Design, Setting, and Participants: In a prospective, longitudinal study, bacterial composition was identified with sequencing of the 16S ribosomal RNA gene in breast milk, areolar skin, and infant stool samples of 107 healthy mother-infant pairs. The study was conducted in Los Angeles, California, and St Petersburg, Florida, between January 1, 2010, and February 28, 2015. Exposures: Amount and duration of daily breastfeeding and timing of solid food introduction. Main Outcomes and Measures: Bacterial composition in maternal breast milk, areolar skin, and infant stool by sequencing of the 16S ribosomal RNA gene.