The infant microbiota hopscotches between community states toward maturation-longitudinal stool parameters and microbiota development in a cohort of European toddlers.

The development of the gut microbiome is critical during early life and is associated with infant health. To test whether this development is deterministic and how it is influenced by factors such as diet and mode of birth, we studied microbiota profiles and fecal parameters of 540 European infants, fed a synbiotic or control infant formula during their first year of life, up to 36 months of age. The diversity of the microbiota gradually increased until 36 months, at which point it resembled adult community states, indicating that microbiota maturation had occurred. However, distinct gut microbiota community states were observed that differed at each stage of maturation. The distribution of infants within the communities even at 36 months was significantly influenced by early life events, with a higher prevalence of infants born by cesarean section having the immature M36-C1 community state at 36 months. The microbial community state at one time point was not predictive of the next; instead, we observed hopscotching of the infant microbiota between different community states. This work provides new longitudinal data on the infant gut microbiome in relation to diet, suggesting that ecosystem development is not deterministic, but that early life events influence the community state of an individual's gut microbiota beyond infancy.