Gut Microbiota Composition in Healthy Japanese Infants and Young Adults Born by C-Section.

Our gut microbiome plays a fundamental role in our health and disease. The microbial colonization of human gut begins immediately at birth and is an indispensable natural process that modulates our physiology and immunity. Recent studies are elegantly revealing how and when these microbes colonize the gut and what elements could potentially influence this natural phenomenon. The vertical mother-to-baby transmission of microbes is a crucial factor for normal development and maturation of newborn's immune, metabolic as well as neurological health. This important and delicate process of gut microbiota development may be impacted by various factors such as birth mode, type of feeding, gestational age at birth, antibiotics exposure in early life, surrounding environment and hygiene settings, and so on. Perturbations in early life gut microbial colonization have been associated with the development of several diseases such as diabetes, obesity, asthma, allergies, celiac disease, neurodevelopmental disorders, and so on. However, it remains unclear whether predisposition to these diseases is due to the lack of acquisition of the mother's (vaginal and perianal) microbes during birth or because of abnormal exposure to unsolicited bacteria. Hence, studies are required to scrutinize the colonization pattern of infant gut microbiome in context to birth mode and also to elucidate how long these differences could persist. In these contexts, we review and discuss some of the findings obtained from recent investigation of the gut microbiota composition in healthy Japanese infants and young adults born vaginally or by C-section.