The present invention provides a multi-peptide composition with antibacterial activity comprising at least 3 peptides with the sequences as set forth in SEQ ID NO:1, 2 or 3 (or related sequences), respectively, in which the SEQ ID NO:1 sequence (or its related sequence) comprises at least two tryptophan residues. In particular the invention provides a new bacteriocin, Garvicin KS. The invention also provides compositions and host cells containing such antibacterial compositions. Uses of the antibacterial composition in treating bacterial infection and products treated with the antibacterial composition are also provided.