Selective Utilization of the Human Milk Oligosaccharides 2′-Fucosyllactose, 3‑Fucosyllactose, and Difucosyllactose by Various Probiotic and Pathogenic Bacteria

Prebiotic human milk
oligosaccharides (HMOs) are found in human
milk, which are not digested by infants but are metabolized by beneficial
gut bacteria. We determined the ability of 57 bacterial strains within
the Family Lactobacillaceae and genera Bifidobacterium and Bacteroides and potentially pathogenic bacteria
to ferment the HMOs 2′-fucosyllactose, 3-fucosyllactose, and
difucosyllactose. In addition, prebiotic galacto-oligosaccharides
(GOS), lactose, fucose, and glucose were evaluated as carbon sources
for these bacterial strains. Bacterial growth was monitored using
the automatic Bioscreen C system. Only certain bifidobacteria, such
as Bifidobacterium longum subsp. infantis and Bifidobacterium bifidum, as well as Bacteroides fragilis, Bacteroides vulgatus, and Bacteroides thetaiotaomicron utilized the studied
HMOs as their sole carbon source, whereas almost all studied bacterial
strains were able to utilize GOS, lactose, and glucose. The selectivity
in utilization of HMOs by only certain bacteria can be advantageous
by promoting beneficial microbes but not supporting the harmful pathogens
in contrast to other less selective prebiotics.