New Insights into the Intrinsic and Extrinsic Factors That Shape the Human Skin Microbiome

Abstract

Despite recognition that biogeography and individuality shape the function and composition of the human skin microbiome, we know little about how extrinsic and intrinsic host factors influence its composition. To explore the contributions of these factors to skin microbiome variation, we profiled the bacterial microbiomes of 495 North American subjects (ages, 9 to 78 years) at four skin surfaces plus the oral epithelium using 16S rRNA gene amplicon sequencing. We collected subject metadata, including host physiological parameters, through standardized questionnaires and noninvasive biophysical methods. Using a combination of statistical modeling tools, we found that demographic, lifestyle, and physiological factors collectively explained 12 to 20% of the variability in microbiome composition. The influence of health factors was strongest on the oral microbiome. Associations between host factors and the skin microbiome were generally dominated by operational taxonomic units (OTUs) affiliated with the Clostridiales and Prevotella. A subset of the correlations between microbial features and host attributes were site specific. To further explore the relationship between age and the skin microbiome of the forehead, we trained a Random Forest regression model to predict chronological age from microbial features. Age was associated mostly with two mutually coexcluding Corynebacterium OTUs. Furthermore, skin aging variables (wrinkles and hyperpigmented spots) were independently correlated to these taxa. IMPORTANCE Many studies have highlighted the importance of body site and individuality in shaping the composition of the human skin microbiome, but we still have a poor understanding of how extrinsic (e.g., lifestyle) and intrinsic (e.g., age) factors influence its composition. We characterized the bacterial microbiomes of North American volunteers at four skin sites and the mouth. We also collected extensive subject metadata and measured several host physiological parameters. Integration of host and microbial features showed that the skin microbiome was predominantly associated with demographic, lifestyle, and physiological factors. Furthermore, we uncovered reproducible associations between chronological age, skin aging, and members of the genus Corynebacterium. Our work provides new understanding of the role of host selection and lifestyle in shaping skin microbiome composition. It also contributes to a more comprehensive appreciation of the factors that drive interindividual skin microbiome variation.

New Insights Into the Skin Microbial Communities and Skin Aging

“…In aging, we detected different species diversities and compositional characteristics of skin microbiomes in different age groups. These differences could be ascribed to continuous self-regulation and self-renewal of skin microbiomes, related to individual's residential environment and host selection pressures (e.g., local physiological status) (Kim et al, 2018;Dimitriu et al, 2019). Consistent with previous studies, higher species diversities of cutaneous bacterial communities were found with aging for both exposed and non-exposed sites (Leung et al, 2015(Leung et al, , 2016aShibagaki et al, 2017).…”

Poor Unstable Midgut Microbiome of Hard Ticks Contrasts With Abundant and Stable Monospecific Microbiome in Ovaries

“…has been identified as part of the healthy skin microbiome and Neisseria sp. is common in the mucosal surface of vertebrate hosts of I. ricinus (Elliott et al, 2005;Dimitriu et al, 2019). In contrast to the ovary, the midgut did not show a core microbiome, as we did not detect any common bacterial genera in all midgut samples.…”

Gut, oral and skin microbiome of Indian patrilineal families reveal perceptible association with age

“…Genus Corynebacterium was highly abundant in first-generation members (Table S7c). Recent study understanding the extrinsic and intrinsic host factors influencing skin microbiome composition suggested that Corynebacterium OTUs were associated with skin aging 66 , specifically with the hyperpigmented spots and wrinkles 66 . With the increasing age, physiological changes occur in the skin structure explains the association of key bacterial taxa in the members of the respective age groups.…”