[General aspects regarding the skin microbiome]

The human body is densely populated by trillions of microorganisms, which are collectively known as the human microbiota. On the outermost barrier, the skin, a plethora of different bacteria and fungi as well as viruses and mites reside. The skin of different body sites shows a high degree of heterogeneity, generating multiple ecological niches. For example, moisture, sebum and sweat promote the growth of different microorganisms. This diversity has hampered a global and objective analysis of the composition of the microbiota in the past. Today, approximately 10 years after the development of metagenome analysis by next generation high-throughput DNA sequencing, these techniques are now established and affordable in research fields. These techniques enable investigations on the microorganisms living in and on body surfaces and represent an important tool in diverse clinical questions. This review addresses new developments in the (physiological) composition of the skin microbiota and briefly summarizes the research techniques applied.