The invention concerns a recombinant nucleic acid molecule encoding an antimicrobial fusion peptidoglycan endopeptidase. The recombinant nucleic acid molecule according to the invention is formed from a nucleic acid encoding a bacterial endopeptidase (lysostaphin) from Staphylococcus simulans and a nucleic acid encoding a second endopeptidase (endolysin) module from Group B streptococcal bacteriophage B30. The encoded fusion endopeptidase has antimicrobial activity and kills both Staphylococcus bacteria and Streptococcus bacteria.