Insights into the Staphylococcus aureus-host interface: global changes in host and pathogen gene expression in a rabbit skin infection model. Staphylococcus aureus

Staphylococcus aureus is an important cause of human skin and soft tissue infections (SSTIs) globally. Notably, 80% of all SSTIs are caused by S. aureus, of which ~63% are abscesses and/or cellulitis. Although progress has been made, our knowledge of the host and pathogen factors that contribute to the pathogenesis of SSTIs is incomplete. To provide a more comprehensive view of this process, we monitored changes in the S. aureus transcriptome and selected host proinflammatory molecules during abscess formation and resolution in a rabbit skin infection model. Within the first 24 h, S. aureus transcripts involved in DNA repair, metabolite transport, and metabolism were up regulated, suggesting an increase in the machinery encoding molecules involved in replication and cell division. There was also increased expression of genes encoding virulence factors, namely secreted toxins and fibronectin and/or fibrinogen-binding proteins. Of the host genes tested, we found that transcripts encoding host IL-8, IL1β, oncostatin M-like, CCR1, CXCR1 (IL8RA), CCL4 (MIP-1β) and CCL3 (MIP1α)-like proteins were among the most highly up-regulated transcripts during S. aureus abscess formation. Our findings provide additional insight into the pathogenesis of S. aureus SSTIs, including a temporal component of the host response. These results serve as a springboard for future studies directed to better understand how/why mild or moderate SSTIs progress to invasive disease. Overall design: Staphylococcus aureus inoculum vs. day 1 of abscess