The first thousand days – intestinal microbiology of early life: establishing a symbiosis

Abstract

The development of the intestinal microbiota in the first years of life is a dynamic process significantly influenced by early-life nutrition. Pioneer bacteria colonizing the infant intestinal tract and the gradual diversification to a stable climax ecosystem plays a crucial role in establishing host-microbe interactions essential for optimal symbiosis. This colonization process and establishment of symbiosis may profoundly influence health throughout life. Recent developments in microbiologic cultivation-independent methods allow a detailed view of the key players and factors involved in this process and may further elucidate their roles in a healthy gut and immune maturation. Aberrant patterns may lead to identifying key microbial signatures involved in developing immunologic diseases into adulthood, such as asthma and atopic diseases. The central role of early-life nutrition in the developmental human microbiota, immunity, and metabolism offers promising strategies for prevention and treatment of such diseases. This review provides an overview of the development of the intestinal microbiota, its bidirectional relationship with the immune system, and its role in impacting health and disease, with emphasis on allergy, in early life.

Modulation of the gut microbiota by prebiotic fibres and bacteriocins

“…The initial colonizers in neonates, which include facultative anaerobes such as Staphylococcus , Streptococcus, Enterococcus and Enterobacter spp., create an environment favourable for subsequent obligate anaerobes, such as Bifidobacterium , Bacteroides, Clostridium and Eubacterium spp. [19,20]. Subsequently, the microbiota slowly develops into an adult-like, more diverse and stable state at around 3 years of age [21,22].…”

Role of secretory IgA in the mucosal sensing of commensal bacteria

“…This is for example the case in the early life period; although neonates are exposed to a unique microbiome prior to birth, as mostly analyzed via 16S rRNA, 53,54 progressive colonization by a developing microbiota ecosystem shortly after vaginal delivery requires control mechanisms to ensure appropriate symbiosis. 55 This colonization process and its interplay with the host is now commonly seen as a key factor to ensure proper post-natal maturation of the gut epithelium barrier and early programming of physiological processes, 2 features which positively influence health throughout life. [56][57][58] It is now generally accepted that induction/completion of immune maturation relies on the presence of newly established commensal intestinal microbes, and that such a process will lead to production of endogenous SIgA, which in turn shapes the composition of the microbiota.…”

The role of early life nutrition in the establishment of gastrointestinal microbial composition and function

“…[1][2][3] Host genetics and environmental factors such as gestational age, delivery mode, diet, pre-and probiotics, antibiotics, maternal weight and stress influence the process. 4 The microbiota acquired in early life have longterm implications for host metabolism and gastrointestinal (GI), immune and neurological function.…”