Fig. 1.
General plan of human skin structure; created with Biorender.com
Fig. 2.
Composition of the skin microbiota; own graphic inspired by Smythe and Wilkinson, 2023
Table I
Eight proposed roles of skin microbiota
| The role of the skin microbiota |
|---|
| 1. Maintaining the acidic pH of the skin (pathogenic microorganisms prefer a more alkaline pH), |
| 2. Prevent settlement and multiplication of pathogenic bacteria by limiting the available food supply (colonization resistance) |
| 3. Keeping the commensal biota intact and eliminating disease-causing microorganisms through the production of antibacterial substances |
| 4. Maintenance of the proper functioning of the epidermal barrier |
| 5. Participation in metabolic processes |
| 6. Impact on the process of tissue maturation in human individual development |
| 7. Maintaining the homeostasis of the immune system by modulating the innate immune response and influencing the development of the acquired response |
| 8. Regulation of pro-inflammatory cytokine expression and activation of the complement system |
Fig. 3.
Host-microbiota interactions; own graphic inspired by Liu et al., 2023
Fig. 4.
Microbial niches on the surface of the skin; created with Biorender.com, inspired by Byrd et al., 2018
Fig. 5.
Eleven factors contributing to changes in skin microbiota; own graphic