P22 Using long-read sequencing to explore the links between strain-level microbial heterogeneity and cutaneous wound pathology

Abstract Introduction and aims It is becoming evident that the microbial inhabitants of our skin play a key role in cutaneous health and disease. However, the contribution of the skin microbiome to wound healing outcome remains incompletely understood. Recent advances have enabled more comprehensive characterization of skin bacterial composition, elucidating a role for specific strains of Staphylococcus aureus in chronic wound repair. Nevertheless, there remains a paucity of data evaluating the mechanisms that drive poor wound healing. The aim of this study was to utilize PromethION metagenomic and whole-genome sequencing to characterize strain-level diversity of the chronic wound microbial landscape and utilize preclinical wound models to elucidate key microbial factors contributing to pathological skin repair. Methods Microbial samples were collected from the skin and wounds of healthy volunteers and patients with chronic wounds. Long-read metagenomic and whole-genome sequencing was used to assess the microbial heterogeneity of skin and wound samples, identifying unique strains associated with healthy and pathological healing outcomes. A multifaceted approach was then used to confirm the bacterial factors driving healing vs. nonhealing states using well-established human and murine models of wound repair. Results We first identified perturbations in the skin microbiome of patients with chronic wounds, which was significantly less diverse than healthy skin and colonized with key bacteria associated with pathogenicity. Whole-genome sequencing of bacterial isolates enabled direct classification of pathogenicity. Links to host healing outcome were confirmed through screening bacterial isolates using a validated human skin wound model. Finally, an in vivo model of murine wound healing determined how nonpathogenic and pathogenic strains of bacteria augment the immune response and contribute to cutaneous repair. Conclusions Collectively, these data provide crucial new insight into the skin and wound microbial landscape, demonstrating the importance of characterizing strain-level bacterial diversity to predict clinical wound healing outcomes.