Neonatal acquisition of bacterial communities and colonization resistance.

The neonatal mouse microbiota does not offer protection against certain bacterial pathogens. The loss of neonatal colonization resistance is mediated by the absence of certain bacterial groups that are more prevalent in adult mice. When these certain bacterial groups, found in the adult, are introduced to the neonate then colonization resistance is restored. Conversely, if you deplete these bacterial groups in the adult mice then colonization resistance is lost. These results identify the gut microbiota as a critical determinant of increased susceptibility to enteric infection during the neonatal period.