Structure and function of the human skin microbiome

Abstract

An abundant and diverse collection of bacteria, fungi, and viruses inhabits the human skin. These microorganisms vary between individuals and between different sites on the skin. The factors responsible for the unique variability of the skin microbiome are only partly understood, but results suggest that host genetic and environmental influences play a major role. Today, the steady accumulation of data describing the skin microbiome, combined with experiments designed to test the biological functions of surface microbes, has provided new insights into links between human physiology and skin microbiota. This review describes some of the current information regarding the skin microbiome and its impact on human health. Specifically, we summarize the present understanding of the function of microbe-host interactions on the skin and highlight some unique features that distinguish skin commensal organisms from pathogenic microbes.

Keywords: microbial diversity; microbiota; skin diseases; skin health.

Figure 1. Dynamics of microbial interactions at the skin surface

Microorganisms form complex interaction networks. Beneficial situations include mutualistic and commensal relationships. In contrast, detrimental relationships describe correlations in which at least one interaction partner is harmed. The mammalian immune system acts to manage microbial communities and orchestrate beneficial microbe–host relationships.

Figure 2. Environment and interactions predict functions of the skin microbiome

The ecology of the skin surface is influenced by many variables including lifestyle, age, emotion, community, genetics, diet, hygiene products and drugs. Under unfavorable conditions, an altered community of microbes can arise on the skin, thus leading to conditions of dysbiosis. Both interactions between microbes and between microbe and host can promote disease. Dysfunction of the capacity to reestablish a normal microbial community may perpetuate chronic disease.