The present invention discloses polypeptides with antibacterial properties and use said polypeptides and/or polynucleotides encoding said polypeptides in the preparation of medicament for the treatment of infectious diseases. The inventors also provide vectors encoding and adapted for expression of the polypeptides and polynucleotides of the invention. The vectors may be used in the preparation of a medicament for the treatment of bacterial infections. Further, the vector of the invention may be used to reduce the load of bacteria in food and/or feed.