The composition of the maternal breastmilk microbiota influences the microbiota network structure during early infancy.

BACKGROUND/PURPOSE(S): Human breastmilk (BM) is important for microbiome maturation in infants across different body sites. Streptococcus and Staphylococcus are considered universally predominant genera in the BM microbiota. However, whether the differential abundance of Streptococcus and Staphylococcus in BM can differentially affect microbiome maturation in infants remains unclear.

METHODS: We recruited exclusively breastfeeding mothers from among the donors of the human milk bank established at National Cheng-Kung University Hospital. The donor mothers provided 35 BM samples at three months (3 M; before introducing children to complementary feeding) and 23 BM samples at six months (6 M; after introducing children to complementary feeding) postpartum. At both time points, samples from different body sites, including nasal swabs, oral swabs and stool, were collected from the mothers and their infants.

RESULTS: Maternal BMI was inversely associated with coagulase-negative Staphylococcus (CoNS) abundance in breastmilk. Staphylococcus caprae representation in BM CoNS showed a negative correlation with Streptococcus abundance. Network analysis revealed that infants fed Staphylococcus-dominated BM had better gut and nasal microbiota networks than infants fed Streptococcus-abundant BM during early infancy.

CONCLUSION: Our work suggests that maternal metabolic status plays a crucial role in Staphylococcus/Streptococcus competition in BM, which in turn can impact the development of the infant microbiota. Our microbiota co-occurrence network analysis might serve as a helpful bioinformatic tool to monitor microbiota maturation during early infancy.