MARCO PIGNATTI1, ENEA G. DI DOMENICO2
1. Clinica Tarabini, Carpi, Italy
2. Department of Biology and Biotechnology “C. Darwin” Sapienza University of Rome, Italy

Abstract

The human skin is the first line of defense against environmental attacks and the invasion of pathogens. The skin is an ecosystem composed of diverse commensal microorganisms, most of which are harmless or beneficial to the host. Microbial colonization is driven by the ecology of the skin surface, topographical location, endogenous host factors, and external environmental agents. Biofilm is the dominant lifestyle of the skin microbiota, representing a critical element in skin health and diseases. The close relationship between the host and microbial biofilms has tremendous implications for major dermatological conditions, making the skin microbiota an attractive target for treating skin disorders. This review summarizes the connection between the skin microbiota, biofilms, and skin diseases in dermatological disorders.

INTRODUCTION
The skin accommodates hundreds of microbial species that constitute the human skin microbiota, including eukaryotes, bacteria, and viruses. After birth, distinct microbial communities colonize the skin at different body sites creating physiological and immunological niches (1). Skin microbiota significantly contributes to health and disease by sustaining the epidermal barrier function, the immune homeostasis, and limiting the growth of pathogenic bacteria (2). The resident microorganisms metabolize nutrients from the host’s skin secretions creating a complex ecological system through dynamic interactions within the microbial communities and with the host. Skin microbiota varies greatly at inter- and intrapersonal levels but is relatively temporally stable (3). Culture- and sequencing-based studies have mainly focused on characterizing the skin’s bacterial and fungal communities. Based on sequencing analysis of phylogenetic marker genes, such as the bacterial 16S ribosomal RNA (rRNA) and fungal internal transcribed spacer (ITS), major bacterial phyla belong to Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes (4, 5). Bacteria a ...