The Staphylococcus aureus regulatory program in a human skin-like environment.

Area of Science:

• Microbiology
• Biotechnology
• Infectious Diseases

Background:

• Staphylococcus aureus is a leading cause of skin and soft tissue infections (SSTIs).
• Current models for studying S. aureus on skin are costly and resource-intensive.
• A need exists for accessible in vitro models mimicking the skin surface environment.

Purpose of the Study:

• To develop a cost-effective, open-source medium (SLM) replicating the human skin surface.
• To investigate the transcriptional response of S. aureus in SLM compared to standard media.
• To explore the role of adhesins in S. aureus adherence to human corneocytes.

Main Methods:

• Development of a chemically defined skin-like medium (SLM).
• RNA-sequencing (RNA-seq) to analyze transcriptional changes in MRSA grown in SLM.
• Quantitative reverse transcription-PCR (qRT-PCR) to assess gene expression under varying conditions.
• Assays to measure MRSA adherence to human corneocytes.

Main Results:

• SLM supports the growth of staphylococcal species.
• SLM induced upregulation of S. aureus virulence factors, including adhesion and proteolysis genes.
• MRSA grown in SLM exhibited enhanced adherence to human corneocytes, dependent on acidic pH.
• Specific adhesins (ClfA, SraP, Fnbps) were implicated in corneocyte adherence.

Conclusions:

• SLM is a viable, cost-effective in vitro model for studying S. aureus on skin.
• SLM promotes the expression of key virulence factors relevant to skin infections.
• The study elucidates the role of specific adhesins and environmental factors (pH) in S. aureus skin colonization.