Scientists made a new peptide called SAAP-148, based on the human peptide LL-37, that can kill tough drug‑resistant bacteria and break down biofilms. In lab tests and on mouse and human skin samples, a short 4‑hour treatment with a cream containing SAAP-148 wiped out infections from MRSA and MDR Acinetobacter, and it didn’t cause the bacteria to become resistant.

Development of novel antimicrobial agents is a top priority in the fight against multidrug-resistant (MDR) and persistent bacteria. We developed a panel of synthetic antimicrobial and antibiofilm peptides (SAAPs) with enhanced antimicrobial activities compared to the parent peptide, human antimicrobial peptide LL-37. Our lead peptide SAAP-148 was more efficient in killing bacteria under physiological conditions in vitro than many known preclinical- and clinical-phase antimicrobial peptides. SAAP-148 killed MDR pathogens without inducing resistance, prevented biofilm formation, and eliminated established biofilms and persister cells. A single 4-hour treatment with hypromellose ointment containing SAAP-148 completely eradicated acute and established, biofilm-associated infections with methicillin-resistant <i>Staphylococcus aureus</i> and MDR <i>Acinetobacter baumannii</i> from wounded ex vivo human skin and murine skin in vivo. Together, these data demonstrate that SAAP-148 is a promising drug candidate in the battle against antibiotic-resistant bacteria that pose a great threat to human health.