This study is aimed to manipulate the composition of the intestinal flora of the infants born by caesarian section through the administration of the probiotic strain "Bifidobacterium bifidum PRL 2010", in order to evaluate its effects on gut dysbiosis during the first 6 month of life.

There has been increasing interest in the field of human microbiome, considering its impact on health and diseases. The gastrointestinal tract represents the most heavily inhabited organ with microorganisms, counting 10 times the total number of human cells; for this reason, the gut microbiome has recently been referred as a proper organ. Intestinal microbial composition is unique for each individual and it is influenced by numerous factors, of which delivery mode is an important one with gestational age of the newborn, type of feeding and intrapartum or neonatal antibiotic therapy. Recent reports suggest that dysbiosis secondary to delivery mode affects the subsequent regulation of immune response and may be associated with several pathologic conditions, for example allergic diseases or obesity. Moreover, gut microbiome seems to impact on neurodevelopment during first six months of life. Bifidobacteria is the most represented group of intestinal microbiota in the newborn, followed by Enterobacteria, and it plays an important role in the infant gut. This includes the fundamental function performed by Bifidobacterium bifidum: it supplies the nutritional material to the rest of the microbial community, particularly Bifidobacterium breve and Bifidobacterium longum infantis that are the other typical bifidobacteria of the newborn. It is a powerful metabolizer of the intestinal mucus and the HMOs (Human Milk Oligosaccharides) present in breast milk. Thanks to its exocitable enzymes, the degradative catabolism occurs in the intestinal environment. Thus, B. bifidum favour the increase in intestinal richness and biodiversity (9), which correlates with the host's state of health. However, bifidobacteria is reduced in infants born by cesarean delivery.

Aim of the study is to assess if the Bifidobacterium Bifidum PRL2010 supplementation effectively ameliorat bifidocentric dysbiosis due to the delivery mode and we want to confirm this by analyzing fecal microbiota in caesarean birth infants.

Inclusion Criteria:

• Healthy infants born by caesarian delivery
• Parents informed written consent

Exclusion Criteria

• Suspension of the administration of the probiotic strain for a period of time exceeding 7 days
• Interruption of the administration of the probiotic strain before the completion of the sixth month
• Replacement of Bifidobacterium bifidum PRL2010 with another strain
• Refusal to collect the fecal sample expressed by parents
• Major congenital birth deformities
• Acute illness at enrollment
• Any condition affecting food intake or metabolism
• Maternal mental and psychosomatic diseases