Microbial ecology and host-microbiota interactions during early life stages

Abstract

The role of human microbiota has been redefined during recent years and its physiological role is now much more important than earlier understood. Intestinal microbial colonization is essential for the maturation of immune system and for the developmental regulation of the intestinal physiology. Alterations in this process of colonization have been shown to predispose and increase the risk to disease later in life. The first contact of neonates with microbes is provided by the maternal microbiota. Moreover, mode of delivery, type of infant feeding and other perinatal factors can influence the establishment of the infant microbiota. Taken into consideration all the available information it could be concluded that the exposure to the adequate microbes early in gestation and neonatal period seems to have a relevant role in health. Maternal microbial environment affects maternal and fetal immune physiology and, of relevance, this interaction with microbes at the fetal-maternal interface could be modulated by specific microbes administered to the pregnant mother. Indeed, probiotic interventions aiming to reduce the risk of immune-mediated diseases may appear effective during early life.

The human gut microbiota: a dynamic interplay with the host from birth to senescence settled during childhood

“…In pregnant, overweight women, a decrease of Bifidobacteria and Bacteroides and an increase of Staphylococci and Enterobacteriaceae (especially Escherichia coli) compared with those of normal weight pregnant women have been reported (60). Other authors have correlated the composition of the newborn gut microbiota to the mothers' weight but found increases in Clostridia, Bacteroides, Staphylococci, and Akkermansia species during pregnancy (61). The increase of Enterobacteriaceae in pregnant women was also functionally related to an increase of ferritin and a reduction of transferrin, while the quantities of Bacteroides were associated with increased levels of high-density lipoprotein (HDL) cholesterol and folic acid (60).…”

“…After delivery, breastfeeding continues to improve the original inoculation of Lactobacilli and Bifidobacteria and of bacteria from the mother's skin, thus making the child's microbiota particularly rich in Bifidobacteria (61).…”

The intestinal microbiota and its role in human health and disease

“…The role of the intestinal microbiota in human health is apparent now because of research that connects changes of the gut microbiota with the risk of diseases. The diversity and total amount of intestinal microbiota is continuously influenced by environmental bacteria, dietary habits, exercises, stress, aging, intake of probiotics/prebiotics, medical treatment with antibiotics or other drugs, host immune system, and the person's genetic background (63,71). While modification of the intestinal microbiota and intestinal environment including mucosal immune system could affect the risk of many kinds of diseases, the strongest influence might occur during early stage of life as described elsewhere (63, 72 -74).…”

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].…”