Maternal Factors Pre- and During Delivery Contribute to Gut Microbiota Shaping in Newborns

14–30% of the subjects (Bifidobacterium, Enterococcus, and the Bacteroides fragilis group). Fallani compared neonatal fecal samples from Sweden, Scotland, Germany, Italy, and Spain. Bifidobacterium genus was predominant (40% average proportion of total detectable bacteria), followed by Bacteroides (11.4%) and Enterobacteria (7.5%; Fallani et al., 2010). Differences in colonization pattern can be observed between infants in industrialized and developing countries (Adlerberth, 2008). Siblings increase the numbers of Bifidobacteria, while pets and country residence show no significance (Penders et al., 2006). Dominguez observed a neonatal colonization corresponding to maternal skin population in case of cesarean section and coincident with maternal vaginal flora in case of vaginal delivery (Dominguez-Bello et al., 2010). Breastfeeding is a significant factor in the determination of neonatal gut microbiota. During lactation, cells from gut-associated lymphoid tissue travel to the breast via the lymphatics and peripheral blood (DonnetHughes et al., 2010). Breast milk gives a flora rich in Bifidobacterium spp. Other obligate anaerobes, such as Clostridium spp. and Bacteroides spp., are more rarely isolated and also Enterobacteria and Enterococci are relatively few. Formula-fed babies are often colonized by other anaerobes in addition to Bifidobacteria and by facultatively anaerobic bacteria; the development of a “Bifidus flora” is unusual (Fanaro et al., 2003). Breastfeeding leads to higher Lactobacillus and lower count of E. coli, Clostridium difficile, B. fragilis (Penders et al., 2006; Fallani et al., 2010). After delivery, breastfeeding continues to enhance the original inoculum by specific lactic acid bacteria and Maternal factors preand during delivery contribute to gut microbiota shaping in newborns