Bern Birth Cohort / Trajectory of Microbiota Maturation in Healthy Bern Infants - a Network Approach

Background: Intestinal microbiota composition is fundamental to human health and undergoes critical changes within the first two years of life. Factors probably influencing the microbiota are the maternal microbiota and the general environment in Switzerland. However, the development of the intestinal microbiota is incompletely understood. Gaining knowledge of the trajectory of microbiota maturation is likely key to the understanding of the pathogenesis of many pathologies in childhood. Aims: The investigators aim for a deep understanding of the maturation of the healthy infant intestinal microbiota regarding composition, diversity and metabolic activities. The investigators aim for identifying parameters affecting microbiota maturation and effects of the microbiota on infant outcome. Methods: The investigators will recruit 250 pregnant mothers who will be followed as mother-baby pairs until 10 years of age. Infants will be followed clinically to determine adequate growth and development as well as pathology including abdominal pain. Epidemiological parameter and infant nutrition will be assessed. The investigators will collect biological samples such as stool, maternal milk, vaginal swaps and skin swaps. Species composition and diversity will be assessed by 16S sequencing. Metagenomic shotgun sequencing and bacterial messenger ribonucleic acid (mRNA) analysis will inform about metabolic potential and metabolic activity of the microbiota. Mass spectrometry will assess the small molecule content of stool and maternal milk samples. Network analysis will be used to assess the complex relationships between bacteria metabolic activities and small molecular content. Expected results: The investigators expect an increase in complexity and metabolic potential and activity with age. Microbiota parameters will differ according to nutrition and might predict infant outcomes such as growth and abdominal pain. Systematic analysis of sequential maternal and infant bacteria samples from stool, skin and maternal milk will help characterizing bacterial transfer from mother to infant Conclusion: The investigators propose an observational study of healthy Bern mother baby pairs with clinical characterisation and biological sampling. Advanced analysis tools will be used to characterise the microbiota and address mechanistic questions.