580 JOURNAL OF COSMETIC SCIENCE
(30) Christensen GJM, Brüggemann H. Bacterial skin commensals and their role as host guardians. Benef
Microbes. 2014 5(2):201–215. doi:10.3920/BM2012.0062
(31) Li D, Wang W, Wu Y, Ma X, Zhou W, Lai Y. Lipopeptide 78 from Staphylococcus epidermidis
activates β-catenin to inhibit skin inflammation. J Immunol. 2019 202(4):1219–1228. doi:10.4049/
jimmunol.1800813
(32) Zheng Y, Hunt RL, Villaruz AE, et al. Commensal Staphylococcus epidermidis contributes to skin
barrier homeostasis by generating protective ceramides. Cell Host &Microbe. 2022 30(3):301–313.e9.
doi:10.1016/j.chom.2022.01.004
(33) Severn MM, Horswill AR. Staphylococcus epidermidis and its dual lifestyle in skin health and infection.
Nat Rev Microbiol. 2023 21(2):97–111. doi:10.1038/s41579-022-00780-3
(34) Dimitriu PA, Iker B, Malik K, Leung H, Mohn WW, Hillebrand GG. New insights into the intrinsic
and extrinsic factors that shape the human skin microbiome. mBio. Guttman DS, ed. 2019 10(4):e00839-
19. doi:10.1128/mBio.00839-19
(35) Kwaszewska A, Sobiś-Glinkowska M, Szewczyk EM. Cohabitation—relationships of corynebacteria and
staphylococci on human skin. Folia Microbiol. 2014 59(6):495–502. doi:10.1007/s12223-014-0326-2
(36) Timm CM, Loomis K, Stone W, et al. Isolation and characterization of diverse microbial representatives
from the human skin microbiome. Microbiome. 2020 8(1):58. doi:10.1186/s40168-020-00831-y
(37) Kim G, Kim M, Kim M, et al. Spermidine-induced recovery of human dermal structure and barrier
function by skin microbiome. Commun Biol. 2021 4(1):231. doi:10.1038/s42003-020-01619-4
(38) Niu Z, Wei G, Mao L, Han L. The causal relationship between skin microbiota and facial aging:
A Mendelian randomization study. Aesthet Plast Surg. Published online July 8, 2024. doi:10.1007/
s00266-024-04217-5
(39) NF EN 1040. Chemical antiseptics and disinfectants—Quantitative suspension test for the evaluation of
the basic bactericidal activity of chemical antiseptics and disinfectants—Test method and requirements
(phase 1). Ed. French Association of Normalization. 2006.
(40) NF EN 1276. Chemical antiseptics and disinfectants—Quantitative suspension test for the evaluation
of the bactericidal activity of chemical antiseptics and disinfectants used in the food industry, in the
home and in the community—Test method and requirements (phase 2, step 1). Ed. French Association
of Normalization. 2010.
(41) ISO 11930:2019. Evaluation of the antimicrobial protection of a cosmetic product. Ed. International
Organization for Standardization. 2019.
(42) Lundov MD, Johansen JD, Zachariae C, Moesby L. Low-level efficacy of cosmetic preservatives. Int J of
Cosmet Sci. 2011 33(2):190–196. doi:10.1111/j.1468-2494.2010.00619.x
(43) Puschmann J, Herbig ME, Müller-Goymann CC. Correlation of antimicrobial effects of phenoxyethanol
with its free concentration in the water phase of o/w-emulsion gels. Eur J of Pharm Biopharm. 2018 131:152–
161. doi:10.1016/j.ejpb.2018.08.007
(44) Kong HH, Andersson B, Clavel T, et al. Performing skin microbiome research: A method to the
madness. J Invest Dermatol. 2017 137(3):561–568. doi:10.1016/j.jid.2016.10.033

581
J. Cosmet. Sci., 75.6, 581–597 (November/December 2024)
*Address all correspondence to Manon Gault, manon.gault@basf.com
Presented at the SCC77th annual scientific meeting &showcase, NY December 11–13, 2023.
First-Time Use of a Droplet-Based Microfluidic Method to
Highlight Specificities of Microbiota Communities From
Sensitive Skin
MANON GAULT, SABRINA LEOTY-OKOMBI, DELPHINE RIVAL AND
VALÉRIE ANDRÉ
BASF Beauty Care Solutions, Lyon, France (M.G., S.L., D.R., V.A.)
Accepted for publication November 26, 2024.
Synopsis
The skin microbiome plays a crucial role in skin health, yet research focusing on the microbiome of sensitive
skin (SS) remains limited. There is a notable absence of a clinical bacterial collection to evaluate the harmful
potential of these bacteria or to assist in selecting suitable cosmetic products. To fill this research gap, we
conducted a comprehensive bacterial analysis using 16S rRNA sequencing and droplet-based microfluidics
to extract and cultivate clinical bacterial isolates from individuals with and without SS, specifically on facial
skin. Our results revealed a decreased abundance of Staphylococci, particularly Staphylococcus epidermidis,
in SS, coupled with an increase in Cutibacterium acnes and Corynebacteria. Additionally, we identified shifts
in the relative proportions of various bacterial species. We isolated hundreds of strains, ultimately selecting
31 representative strains for ingredient testing. Notably, certain strains of Cutibacterium acnes from SS
patients were linked to reduced keratinocyte viability and heightened interleukin-8 production, indicating
potential virulence.
INTRODUCTION
Up to 70% of women and 60% of men report having sensitive skin (SS).1 SS syndrome is
a complex clinical phenomenon defined by the self-reported presence of different sensory
perceptions, including tightness, stinging, burning, tingling, pain, and pruritus, even
though objectively measurable signs of irritation are not always present. Although the
skin microbiome is considered important to skin health, the relationship between the skin
microbiome and skin sensitivity has received little attention.
The skin serves as a barrier between the body’s internal physiology and the external
environment, which means that the skin microbiota is continually exposed to external
factors such as UV rays and pollution, both of which can modify its composition.2-4