Characterisation of the skin and oral microbiome of younger and older adults in a UK population

The human microbiome has been implicated in contributing to various aspects of human health and disease. One aspect is the ageing process, which in humans is exhibited through physical and functional deterioration. During ageing the microbiome undergoes taxonomic shifts, some contribute to various chronic comorbidities in ageing, while others are due to ageing changes in the host. Studies of the human skin and oral microbiomes in the UK were revealed to account for a combined 4% of UK microbiome research in 2021, therefore there is a lack of knowledge about these microbiomes in UK populations. A suitable sampling strategy for obtaining skin and oral microbiome samples in non-clinical settings was implemented on a participant population of 30 young adults (aged 20-40 years old), and 29 older adults (aged 60-80 years old). Two skin samples (from the right antecubital fossa and the right face cheek) and one oral (an oral rinse) were taken from each participant, during sampling metadata about participant health and hygiene habits were also obtained. An optimised bioinformatics pipeline was developed to enable analysis of 16S rRNA sequencing of each sample. Analysis of the skin microbiomes revealed significant differences in beta diversity associated with age and with females in age whereas the male populations tended to be similar, specifically a reduction in Cutibacterium acnes population was demonstrated. With increasing age, the oral microbiome was characterised by an increase in various Prevotella species and an increase in the pathogenic potential of the microbiome metabolome, however participant health rather than gender was identified to have an influence on these differences. Across all microbiomes a reduction in community resilience in age was seen. Overall, this study identified changes in all microbiomes investigated associated with ageing in a UK population, and that these changes are different across the skin and oral microbiomes.