The present invention is directed to isolated and chimeric polypeptides of bacteriophage origin having antibiotic activity and use thereof in the treatment and control of bacterial infections. Specifically, the present invention is directed to the use of a novel antibacterial polypeptide derived from bacteriophage F87s/06 and chimeric constructs thereof, and their use for the treatment and control of infections caused by gram-positive bacteria, including Staphylococcus aureus.