Influence of Chemical- and Natural-Based Lotions on Bacterial Communities in Human Forearm Skin

ABSTRACT

Purpose of this study was to evaluate the influence of a lotion on the bacterial community in the human forearm skin. The chemical- and natural-based lotions were applied on the left and right inner forearm skins, respectively, of 14 participants, who cleansed forearm skin using sterilized cotton swabs. The germs on cotton swabs were analyzed using libraries of PCR amplicons. The genetic diversity of the bacterial communities detected on the natural-based lotion-applied skin (NLS) was significantly higher than that of the bacterial communities on the chemical-based lotion-applied skin (CLS) in all participants, except two. The diversity was estimated based on operational taxonomic unit (OTU), Chao1, Shannon, and Simpson indices. Bacterial communities obtained from the CLS and NLS were phylogenetically separated into 5 and 3 monophyletic groups, respectively, based on lotion types. The taxonomic distribution of the bacterial communities, which were composed of 198 genera in 14 phyla in the CLS and NLS, respectively, was irregularly and biasedly separated into 2 groups based on the lotion types. Among the 14 phyla, Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria were found to be relatively dominant, and 15 of the 198 genera, including Methylobacterium, Propionibacterium, Pseudomonas, Staphylococcus, Streptococcus, and Bacillus were relatively dominant (>0.5%). The taxonomic distribution of dominant bacterial communities from CLS and NLS was irregularly and biasedly separated without relation to the lotion types. In conclusion, the chemical- and natural-based lotions were responsible for changing or influencing the genetic diversity, phylogenetic separation, and taxonomic distribution of skin bacterial communities.