Park T.
Amorepacific, South Korea

Diverse bacterial communities can be found on the surface of skin, but relatively there were few comprehensive studies, because the normal and commensal communities of human skin compromises a complex communities.
Staphylococcus epidermidis (S. epidermidis), the most prevalent of many cutaneous resident microflora, is generally innocuous [1]. One of its role is competitive protection of the skin against all forms of pathogenic bacteria. Staphylococcus aureus (S. aureus), a opportunistic human and animal pathogen, is a gram-positive bacterium that commonly lives or colonizes on human skin and causes skin diseases such as atopic dermatitis [2]. Therefore, we assumed that S.epidermidis is a beneficial skin microflora, but S. aureus is pathogenic. The aim of this study is to investigate the prebiotic effect of α-
Glucan on skin microflora, Staphylococcus.

Chemicals and Strains
The test material, α-Glucan, is an oligosaccharide obtained by enzymatic synthesis from natural sugars. (INCI: α-Glucan oligosaccharide)
S. epidermidis (ATCC 12228) and S. aureus (ATCC 6538) was grown in tryptic soy broth (TSA) (Difco, USA) in 32℃ incubator for 24 h to reach the exponential phase. Formation of the microorganisms was checked by optical microscope
Study of the Metabolisation
Strains were incubated in a culture medium containing a carbonated substrate (α-Glucan vs glucose), at a concentration of 0.5%. After 24 hours of culture, the residual substrate content was quantified by means of ion chromatography (IC) systems.
Study of the Growth rate
To distinguish the growth rate of two strains, we measured the number of colonies for each time. 1Ⅹ 106 CFU/mL S. epidermidis was inoculated to PBS with 0.5% α-Glucan in sterile condition, and counted the number colonies in 0 h, 4 h, 8 h and 24 h by agar dilution susceptibility test. S. aureus proceed to the same way. After checking the number, we expressed as a Log10 value.

In order to evaluate the prebiotic effect of α-Glucan, we compared the growth rate and metabolisation of each strains.
According to the result, S. epidermids had a higher growth rate with 0.5% α-Glucan than S. aureus.
The initial inoculation was 6.342 in S. epidermidis and 6.079 in S. aureus. After incubating for 24 h, a final concentration was 8.491 in S. epidermidis and 6.944 in S. aureus. According to the metabolisation study, we found that residual substrate was about 34.05% in S. epidermidis and 8.18% in S. aureus. The α-Glucan was metabolized faster and better by thebeneficial microflora (S epidermidis), but undesirable flora (S.aureus)

Our study provided that α-Glucan stimulated the growth of beneficial resident flora, and its bio-selectivity as a substrate will enable to restrict the growth of pathogenic flora. Ecological balance is very important to prevent invasion of external pathogen and maintain the barrier function of skin. Therefore, we concluded that α-Glucan had the possibility of prebiotics effect, and expected that the product containing this material has a potential benefit for skin health.

Keywords: Prebiotics, Probiotics, α-Glucan oligosaccharide, Staphylococcus epidermidis,
Staphylococcus aureus, Skin microflora

Park T. (2016). The prebiotic effect of Gluco-oligosaccharide on skin microflora, Staphylococcus. Conference Proceedings of IPC2016. Paper presented at the International Scientific Conference on Probiotics and Prebiotics, Budapest (p. 112.). IPC2016

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