The invention provides a peptide comprising: a core amino acid sequence, which is identical or similar to the amino acid sequence of a member of the Cecropin family. The invention further provides a nucleic acid sequence encoding the peptide and a vector comprising said nucleic acid. The invention further provides a pharmaceutical composition comprising said peptide or said nucleic acid. The invention further provides methods of treating an infection, overcoming inherent or acquired resistance of a microorganism to an antibiotic agent or disinfecting a wound, the methods comprises administering the peptide to a subject in need thereof.