Capsicumine: a new peptide from red peppers turns out to be a powerful antibiofilm agent and displays a new mechanism of action, matrix anti-assembly

Biofilm-forming bacteria are an important reservoir of nosocomial infections, and source of antibiotic resistance and tolerance. These bacteria are enclosed in a complex matrix that allows them to adhere to medical devices and tissue, and which also protects against antibiotics and immune systems. Advances in antibiofilm strategies for targeting the biofilm matrix are therefore extremely relevant in the fight against multidrug-resistant and/or -tolerant bacteria. Plants are constantly attacked by a wide range of pathogens, and have protective factors such as peptides to defend themselves. These peptides are common components in red pepper seeds, and here we investigate and identify a new antibiofilm peptide, “capsicumicine.” We demonstrate that capsicumicine prevents methicillin-resistant adhesion as well as biofilm establishment and maintenance via a new extracellular “matrix anti-assembly” (MAA) mechanism of action. In this manner, capsicumicine disturbs the construction of the matrix, and therefore its functioning. Importantly, the peptide is not an antibiotic and it is not cytotoxic, thus capsicumicine is an exciting new alternative treatment for prevention of biofilm infections.