Human Milk Oligosaccharides Promote the Growth of Staphylococci

Abstract

f Human milk oligosaccharides (HMO), which constitute a major component of human milk, promote the growth of particular bacterial species in the infant's gastrointestinal tract. We hypothesized that HMO also interact with the bacterial communities present in human milk. To test this hypothesis, two experiments were conducted. First, milk samples were collected from healthy women (n ‫؍‬ 16); culture-independent analysis of the bacterial communities was performed, HMO content was analyzed, and the relation between these factors was investigated. A positive correlation was observed between the relative abundance of Staphylococcus and total HMO content (r ‫؍‬ 0.66). In a follow-up study, we conducted a series of in vitro growth curve experiments utilizing Staphylococcus aureus or Staphylococcus epidermidis and HMO isolated from human milk. HMO exhibited stimulatory effects on bacterial growth under various nutritional conditions. Analysis of culture supernatants from these experiments revealed that HMO did not measurably disappear from the culture medium, indicating that the growth-enhancing effects were not a result of bacterial metabolism of the HMO. Instead, stimulation of growth caused greater utilization of amino acids in minimal medium. Collectively, the data provide evidence that HMO may promote the growth of Staphylococcus species in the lactating mammary gland. Human milk oligosaccharides (HMO) are complex glycans highly abundant (ϳ5 to 15 g/liter) in human milk (5,6,24). Representing a diverse collection of structures, almost 150 distinct forms of HMO have been identified (42,43). Based upon their structures, HMO can be classified as simple (sialylated or fucosylated lactose compounds made of three sugar units) or complex (composed of differentially sialylated or fucosylated repeats of lacto-N-biose or N-acetyllactosamine linked to a lactose motif). Interestingly, HMO patterns are highly unique to individual women, and their concentrations vary over the course of lactation, with levels peaking in colostrum and lower concentrations in mature milk (8,12,15,39).From an evolutionary standpoint, it is logical that because the mammary gland exerts a substantial amount of energy to produce these compounds, HMO likely promote the fitness of the offspring even though the infant is largely unable to metabolize them (1, 14, 16). Research from several groups suggests the possibility that HMO are capable of interacting with an infant's gastrointestinal microbiota to promote his or her health (10,27,30,35,38). Indeed, some of the first studies in this area noted the capacity of HMO to promote growth of Bifidobacterium bifidum, a species overrepresented in the gastrointestinal tract of the breast-fed, but not formula-fed, infant (17,29,40). Over 50 years later, research has confirmed that the genetic capacity to metabolize these compounds is conserved among bifidobacteria species common in the infant's gastrointestinal tract (38). These findings suggest that HMO may serve a prebiotic function in selectively promoting the...

Milk Glycans and Their Interaction with the Infant-Gut Microbiota

“…on HMOs. Hunt et al (2012) reported that HMOs have growth-stimulating properties on Staphylococcus aureus and Staphylococcus epidermidis ; however, analysis showed no HMO consumption from the spent media, suggesting factors other than HMOs caused the growth stimulation. Bacteroides thetaiotaomicron and Bacteroides fragilis utilize HMOs by inducing the same genes that are involved in mucin utilization (Marcobal et al 2011).…”

Pilot study on novel skin care method by augmentation with Staphylococcus epidermidis, an autologous skin microbe – A blinded randomized clinical trial

“…A number of basic cosmetics contain oligosaccharides to facilitate the colonization of S. epidermidis; however, they also have the undesirable property of promoting the growth of S. aureus [12]. In contrast, the continuous application of individualized S. epidermidis samples has the advantage of leading to only a specific increase in S. epidermidis.…”

“…Thus, numerous basic cosmetics that facilitate the growth of S. epidermidis on the skin surface have been developed to exploit the skin care benefits induced by S. epidermidis. However, the stimulating effects of these basic cosmetics on the colonization of S. epidermidis are often insufficient because of the differences in the skin characteristics of individuals and the gradual depletion of active substances in basic cosmetics induced by the metabolism of the skin microbiota itself [12].…”

Clinical applications of bioactive milk components

“…75 Additional in vitro data suggests that the supplementation of infant formula with human milk oligosaccharides enhanced growth of opportunistic pathogens S. aureus and Staphylococcus epidermidis, and culture-independent data correlates concentrations of human milk oligosaccharides with the presence of Staphylococcus species in human milk samples. 76 A small clinical trial of formula enriched with galacto-oligosaccharide or human milk oligosaccharide from donor milk administered to premature infants reported no appreciable difference in stool bacterial composition, noting that antibiotic use was widespread among the research subjects. 77 Limited supply currently precludes extensive trials of human milk oligosaccharides as prebiotic agents in humans and animals.…”