Science

Fredrik Backhed, Josefine Roswall, Yangqing Peng, Qiang Feng, Huijue Jia, Petia Kovatcheva-Datchary, Yin Li, Yan Xia, Hailiang Xie, Huanzi Zhong, Muhammad Tanweer Khan, Jianfeng Zhang, Junhua Li, Liang Xiao, Jumana Al-Aama,Dongya Zhang,Ying Shiuan Lee, Dorota Kotowska, Camilla Colding, Valentina Tremaroli, Ye Yin, Stefan Bergman, Xun Xu, Lise Madsen, Karsten Kristiansen, Jovanna Dahlgren,and Wang Jun

The gut microbiota is central to human health, but its establishment in early life has not been quantitatively and functionally examined. Applying metagenomic analysis on fecal samples from a large cohort of Swedish infants and their mothers, we characterized the gut microbiome during the first year of life and assessed the impact of mode of delivery and feeding on its establishment. In contrast to vaginally delivered infants, the gut microbiota of infants delivered by C-section showed significantly less resemblance to their mothers. Nutrition had a major impact on early microbiota composition and function, with cessation of breast-feeding, rather than introduction of solid food, being required for maturation into an adult-like microbiota. Microbiota composition and ecological network had distinctive features at each sampled stage, in accordance with functional maturation of the microbiome. Our findings establish a framework for understanding the interplay between the gut microbiome and the human body in early life.