Microbes and little men : the chance and necessity of holobiosis

This lecture reviewed the major stages in a child's development from conception to the second year of life, the "first thousand days". It raised the possibility of a placental and meconium microbiota that could play a role in fetal development, in particular the antenatal maturation of the immune system. He presented the first available information on the construction of the newborn's microbiota and the risks of altering it through procedures such as Caesarean sections, which "short-circuit" the possibility of early colonization of the child's digestive tract by the mother's vaginal and fecal flora, or the heavy use of antibiotics. These "post-modern" situations deplete the child's microbiota and seem capable of precipitating the onset of worryingly growing diseases such as asthma, allergy and atopy, obesity and diabetes. This is a new field of medicine that deserves attention, as early interventions to enrich and diversify the intestinal microbiota could help prevent these pathologies.