Fig. 2
From: Determinants of microbial colonization in the premature gut
Factors shaping the preterm infant (PTI) gut microbiota during early life and evolution
During the first weeks after birth, the human infant gut is colonized by facultative anaerobes, such as Enterobacteriaceae, Streptococcus, Enterococcus, and Staphylococcus. PTIs are more highly colonized by Staphylococcus than are full-term infants (FTIs) during this period, and PTIs gradually become dominated by anaerobic genera, including Bifidobacterium, Bacteroides, and Clostridium. Between 10 days and 3 months of age, Enterococcaceae and Lactobacilli dominance is observed in premature babies. After cessation of breastfeeding and the addition of solid foods, the gut microbiota gradually becomes dominated mainly by members of the anaerobic class Clostridia, a process required for maturation into an adult-like microbiota