Simple Summary Neonates are highly susceptible to intestinal infections; this has been generally ascribed to the immaturity of the immune system, but other factors might contribute. The composition of the gut microbiota is a key factor, as the microbiota protects the host against colonization by pathogens. The neonatal gut microbiota is less diverse and lacks two taxa that are dominant in older intestines: members of the orders Clostridiales and Bacteroidales. Microorganisms are closely related to the body's physiological activities and growth and development of the body, and participate in ma...
