1 Scientific RepoRts | 7: 4039 | DOI:10.1038/s41598-017-04197-4 www.nature.com/scientificreports Human age and skin physiology shape diversity and abundance of Archaea on skin Christine Moissl-eichinger 1,2 , Alexander J. probst 3 , Giovanni Birarda 4,7 , Anna Auerbach 5 , Kaisa Koskinen 1,2 , Peter Wolf 6 & Hoi-Ying N. Holman 7 the human skin microbiome acts as an important barrier protecting our body from pathogens and other environmental infuences. Recent investigations have provided evidence that Archaea are a constant but highly variable component of the human skin microbiome, yet factors that determine their abundance changes are unknown. Here, we tested the hypothesis that the abundance of archaea on human skin is infuenced by human age and skin physiology by quantitative PCR of 51 diferent skin samples taken from human subjects of various age. Our results reveal that archaea are more abundant in human subjects either older than 60 years or younger than 12 years as compared to middle-aged human subjects. These results, together with results obtained from spectroscopy analysis, allowed us gain frst insights into a potential link of lower sebum levels and lipid content and thus reduced skin moisture with an increase in archaeal signatures. Amplicon sequencing of selected samples revealed the prevalence of specifc eury- and mainly thaumarchaeal taxa, represented by a core archaeome of the human skin. Te human skin is our primary interface to the external environment. With a total area of 1.8 m 2 and the abun- dance of folds, invaginations and appendages, the skin is populated by a diverse community of microorgan- isms termed the skin microbiome. Te overwhelming majority of these microorganisms are commensals, which impede the invasion of more pathogenic species, enable host surface-microbe interactions, and provide vital functions to the overall cutaneous health 1 . The skin microbiome composition depends largely on cutaneous structure and chemical composition, refected by the location on the body, skin constitution (epidermis or dermis), appendages (glands or follicles), and skin topographical variability (e.g. moist or dry sites) 1–5 . For example, bacterial populations difer between sebaceous (oily, waxy), moist or dry skin areas. Propionibacterium and Staphylococcus were reported to be found mainly in sebaceous skin sites such as the face and torso, whereas Corynebacterium, Staphylococcus and diferent ß-Proteobacteria in moist areas (armpit, arm and knee fossa). Dry areas also ofen have the richest microbial communities 6 and seem to be dominated by β-Proteobacteria, Corynebacterium and Flavobacteriales 1 . Te skin microbiome composition is also infuenced by host factors including immune system, age and sex 6 . Te skin of a new-born frst adopts the microbiome of either mother’s vagina, or the skin microbiome of family members in case of a Caesarean section 7 . Te baby’s microbiome changes rapidly within the frst months, devel- ops further in the following years and reaches an adult microbiome composition at sexual maturity 7, 8 . Te efect of sex on the human microbiome was found to substantially infuence the microbial community composition of skin, most likely due to diferent steroid productions 6, 9 . Tis sex efect is not limited to the micro- bial palm community 4 , it exists almost in all body sites, especially the glabella area 2 , where the cosmetics applica- tion could be a trigger 10 . Te infuence of age and sex on the skin microbiome composition was further confrmed 1 Medical University of Graz, Department of Internal Medicine, Auenbruggerplatz 15, 8036, Graz, Austria. 2 BioTechMed-Graz, Mozartgasse 12/II, 8010, Graz, Austria. 3 Department of earth and Planetary Science, University of California, Berkeley, 307 McCone Hall, Berkeley, CA, 94720, USA. 4 elettra – Sincrotrone trieste, Strada Statale 14 - km 163,5 in AREA Science Park, 34149, Basovizza, Trieste, Italy. 5 University of Regensburg, Department of Microbiology and Archaea Center, Universitaetsstr. 31, 93053, Regensburg, Germany. 6 Medical University of Graz, Department of Dermatology, Auenbruggerplatz 8, 8036, Graz, Austria. 7 Berkeley Synchrotron infrared Structural Biology Program, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California, United States of America. Correspondence and requests for materials should be addressed to C.M.-E. (email: christine.moissl- eichinger@medunigraz.at) Received: 19 January 2017 Accepted: 10 May 2017 Published: xx xx xxxx OPEN