Abstract
Strain-level variation in Staphylococcus aureus is a factor that contributes to disease burden and clinical outcomes in skin disorders and chronic wounds. However, the microbial mechanisms that drive these variable host responses are poorly understood. To identify mechanisms underlying strain-specific outcomes, we perform high-throughput phenotyping screens on S. aureus isolates cultured from diabetic foot ulcers. Isolates from non-healing wounds produce more staphyloxanthin, a cell membrane pigment. In murine diabetic wounds, staphyloxanthin-producing isolates delay wound closure significantly compared with staphyloxanthin-deficient isolates. Staphyloxanthin promotes resistance to oxidative stress and enhances bacterial survival in neutrophils. Comparative genomic and transcriptomic analysis of genetically similar clinical isolates with disparate staphyloxanthin phenotypes reveals a mutation in the sigma B operon, resulting in marked differences in stress response gene expression. Our work illustrates a framework to identify traits that underlie strain-level variation in disease burden and suggests more precise targets for therapeutic intervention in S. aureus-positive wounds.