# Genetic Characteristics Associated with Probiotic Functions in Four Indonesian Skin Microbiome-Derived Bacterial Strains

## TL;DR

This study analyzes the genomes of four skin bacteria to identify genetic traits linked to probiotic functions and safety for potential use in cosmetics or skin health.

## Contribution

The novel contribution is the identification of probiotic-related genes and safety profiles in four Indonesian skin-derived bacterial strains.

## Key findings

- Each strain contains adhesin-encoding genes, but only two have genes for metabolism improvement.
- S. hominis MBF12-19J showed the best antibiotic resistance profile.
- B. subtilis MBF10-19J exhibited amoxicillin resistance and requires careful evaluation.

## Abstract

The human skin microbiome has gained considerable attention as a resource for the development of innovative probiotics for cosmetic purposes or promoting skin health. However, the evaluation of new probiotic strains to ensure their “generally recognized as safe” (GRAS) status remains challenging. Here, we have subjected the annotated draft genome sequences of four human skin-derived bacterial strains, namely Bacillus subtilis MBF10-19J, Micrococcus luteus MBF05-19J, Staphylococcus hominis MBF12-19J, and Staphylococcus warneri MBF02-19J, to bioinformatic analyses to detect the genes associated with important probiotic traits, as well as undesirable characteristics such as antibiotic resistance, virulence factors, and toxic metabolites. Each bacterium harbors at least one type of adhesin-encoding gene, while only S. hominis MBF12-19J and S. warneri MBF02-19J contain the putative genes encoding enzymes for metabolism improvement. In vitro assays, including antibiotic susceptibility and antimicrobial activity testing, revealed strain-specific safety characteristics that complement the genomic findings. With regard to antibiotic resistance determinants, S. hominis MBF12-19J showed the most favorable profile, S. warneri MBF02-19J and M. luteus MBF05-19J appeared suitable when used with appropriate caution, and B. subtilis MBF10-19J exhibited amoxicillin resistance, i.e., warrants careful evaluation. Further in vivo validation is needed to determine whether these strains do indeed comply with GRAS evaluation frameworks.