oligosaccharides

Human milk is the gold standard for feeding babies — its benefits are well-known. And now formula manufacturers are bringing their products closer to the composition of breast milk by the addition of compounds — oligosaccharides — that are commonly found in mothers' milk.
Breastfed babies who consume a particular type of sugar in their milk are more likely to be protected from colonization by Group B Streptococcus — a bacteria, which is a major cause of meningitis and other serious ailments in newborns. These sugars — oligosaccharides — are thought to encourage the growth of non-pathogenic bacteria in the baby's GI tract which, in effect, "crowds out" the dangerous ones.