Background
Development of the infant gut microbiota during early life impacts short- and long-term health. Infant gut bacterial communities are likely influenced by those present in human milk, the maternal gut, and infant oral cavity. However, little is known about temporal development of these microbiomes over the first 4 months of life.
Aim
To characterize temporal development of bacterial communities in maternal and infant samples over the first four months of life.
Methods
Maternal faecal, infant faecal, human milk, and infant oral samples were collected 2-5 days after birth, then monthly over the first 4 months of life. Full-length 16S rRNA gene sequencing was performed to analyse bacterial profiles in each sample.
Results
Bacterial profiles were unique to each sample type (AMOVA: all P<0.01). Streptococcus sp. (43.7%) and Staphylococcus sp. (28.7%) dominated human milk samples, whilst, the infant faecal microbiome was heavily populated by Bifidobacterium sp. (55.9%). Infant oral samples were dominated by Streptococcus sp. (42.8%) and Gemella sp. (16.5%). Maternal faecal samples were the most diverse (Shannon diversity: all P<0.01) and contained large numbers of Bacteroides sp. (22.5%). We observed temporal changes over the four-month period for some of the most abundant bacterial genera in the maternal and infant microbiomes. In human milk samples, the relative abundance of Streptococcus sp. increased, and Staphylococcus sp. decreased between 1-2- and 1-4-month samples (P<0.05), whilst Bifidobacterium sp. significantly increased from day 2-5 to 3-month infant faecal samples (P<0.05). Streptococcus sp. significantly increased from day 2-5 to 3-month infant oral samples. In maternal faecal samples, Bacteroides sp. significantly increased from day 2-5 to both 2- and 3-month samples (P<0.05).
Conclusion
This study is the first Australian study to track longitudinal development of maternal and infant microbiomes. Our findings demonstrate temporal development within each sample type, and that certain bacteria in infant and maternal microbiomes significantly change over the four-month period. Understanding temporal development may provide opportunities to enhance infant health.