Influence of Staphylococcus aureus Infection on Partially Ischemic Excisional Skin Wounds.

Background: Skin wounds, whether medically or incidentally induced, are always at a risk of becoming infected, but the infection risks are greater when the wounds are recovering under ischemic, poorly perfused conditions. Staphylococcus aureus, which frequently infects cutaneous and soft tissue, can infect to a greater extent when wounds are poorly perfused. Bad as this may be, both MSSA and MRSA strains of S. aureus can cause severe infections, with MRSA being considered more aggressive.

Methods: In this study, we used a lagomorph ear excisional wound model to initially test the influence of partial ischemia on uninfected wound healing. We then subsequently test the same ischemic injury model under an active MSSA infection and compared these wounds against normally perfused MSSA-infected wounds. Lastly, we test whether differences in healing exist between MSSA-infected and MRSA-infected wounds, both under the same ischemic model.

Results: The data suggest that partial ischemia considerably reduces healing of noninfected wounds (epithelial gap P=^∗∗∗∗, granulation gap P=^∗∗∗, and granulation area P=^∗∗∗∗). Similarly, partial ischemic wounds coupled with MSSA infection display healing impairments against likewise-infected wounds healing under normal perfusion (epithelial gap P=^∗, granulation gap P=^∗, and granulation area P=^∗∗). No significant differences were observed between MSSA-infected and MRSA-infected wounds healing under ischemia.

Conclusion: The data produced quantitative differences in healing under various conditions consequent to ischemia and S. aureus infection. Although it is well recognized that ischemia and infection adversely influence healing, by testing these conditions, we determined the detrimental magnitude such circumstances inflict on skin healing, thereby providing a relative reference to compare and gauge when met with similar conditions clinically.