P47 Exploring the bidirectional relationship between skin ageing and microbiota using long-read sequencing

Abstract Introduction and aims Human skin hosts a diverse and unique microbiota, playing crucial roles in health, protection and immunity. While ageing alters skin microbiota composition, the causal relationship between these changes and the ageing process remains poorly understood. This study investigates the bidirectional relationship between skin ageing and microbiota. Methods Healthy volunteers recruited for this study were categorized as young (18–30 years) and elderly (> 60 years). Swabs from the forehead, forearm and foot were used for bacterial isolation and metagenomic profiling using Nanopore sequencing. Age-related biophysical parameters were measured using DermaLab Combo®. Results Bacterial profiling revealed important age-associated differences. Younger individuals exhibited higher sebum content and a greater abundance of lipophilic Cutibacterium on the forehead, whereas Corynebacterium was more abundant in the elderly. The forearm displayed a more diverse and evenly distributed microbial community, with Staphylococcus being more prevalent in young volunteers’ arms. Additionally, there was an increase in potentially opportunistic pathogens, such as Escherichia and Corynebacterium. Staphylococcus dominated both age group’s microbiomes on the feet, with a moderate increase in the younger group. Alpha and beta diversities showed considerable disparities between groups in different body sites. Biophysical properties varied more between body location within individuals than between age groups, highlighting the influence of intrapersonal differences. Ongoing whole-genome analyses aim to further explore bacterial pathways linked to age. Conclusions By combining the power of long-read sequencing with biophysical measures we were able to explore age-related bacterial changes across skin regions. PromethION sequencing provided unprecedented insight into the skin’s strain-level diversity. Our findings suggest that microbial changes may be both a cause and a consequence of biophysical changes in the skin. For further explorations, whole-genome studies are being conducted to unveil the mechanisms behind microbiome alterations on the skin, paving the way for groundbreaking advances in understanding and addressing skin ageing.