A natural skin peptide called p4 (from chemerin) can kill MRSA bacteria and works together with the body’s own antimicrobial peptide LL‑37. In mouse skin tests, applying p4 lowered the amount of MRSA and reduced inflammation, showing it could be a useful skin‑protective agent, though it’s still early‑stage research.

Chemerin-derived peptide Val⁶⁶-Pro⁸⁵ (p4) restricts the growth of a variety of skin-associated bacteria, including methicillin-resistant <i>Staphylococcus aureus</i> (MRSA). To better understand the antimicrobial potential of chemerin peptide, we compared p4 activity against MRSA <i>in vitro</i> to cathelicidin LL-37, one of the key endogenous peptides implicated in controlling the growth of <i>S. aureus</i>. The efficacy of p4 was also validated in relevant experimental models of skin pathology, such as topical skin infection with community-acquired MRSA, and in the context of skin inflammatory diseases commonly associated with colonization with <i>S. aureus</i>, such as atopic dermatitis (AD). We showed that p4 collaborates additively with LL-37 in inhibiting the growth of <i>S. aureus</i>, including MRSA, and that p4 was effective <i>in vivo</i> in reducing MRSA burden. p4 was also effective in reducing levels of skin-infiltrating leukocytes in <i>S. aureus</i>-infected AD-like skin. Taken together, our data suggest that p4 is effective in limiting <i>S. aureus</i> and, in particular, MRSA skin infection.