The invention relates to peptide derivatives of general formula (I): R1-AA1-AA2-R3-AA4-R2  (I) their stereoisomers, mixtures thereof, and their cosmetically or pharmaceutically acceptable salts, a method for obtaining them, cosmetic or pharmaceutical compositions containing them and their use for the treatment, care and/or cleansing of those conditions, disorders and/or pathologies of the skin, mucosae, scalp and/or nails resulting from microorganism proliferation or being at risk of microorganism proliferation.