Local inflammation exacerbates the severity of Staphylococcus aureus skin infection

Area of Science:

• Immunology
• Microbiology
• Dermatology

Background:

• Staphylococcus aureus is a primary cause of bacterial skin infections.
• The relationship between bacterial burden and clinical severity in skin infections is not fully understood.

Purpose of the Study:

• To investigate the role of the host inflammatory response in Staphylococcus aureus skin infection severity.
• To determine if T cell deficiency influences lesion size and inflammatory markers.

Main Methods:

• Comparison of lesion size and bacterial burden in athymic nude mice versus wild-type mice during S. aureus skin infection.
• Measurement of myeloperoxidase, IL-17A, and CXCL1 levels in skin lesions.
• Assessment of T cell deficiency impact using TCR βδ (-/-) mice and adoptive T cell transfer.

Main Results:

• Lesion size did not correlate with bacterial burden in the mouse model.
• Athymic nude mice exhibited smaller skin lesions with reduced myeloperoxidase, IL-17A, and CXCL1 levels compared to wild-type mice, despite similar bacterial loads.
• T cell deficiency did not account for the observed differences in lesion size.

Conclusions:

• The clinical severity of S. aureus skin infections is primarily dictated by the host's inflammatory response.
• This inflammatory response appears to be T cell-independent in the context of skin infection severity.
• Findings highlight the inflammatory component over bacterial load in driving S. aureus skin infection pathology.