The routine use of antibiotics to battle Streptococcal pathogens has produced a new class of superbug—multi-drug resistant streptococci resulting in a need for new antimicrobials. The LambdaSa2 prophage endolysin gene harbors an amidase-5 (endopeptidase), an amidase-4 (glycosidase) domain and two Cpl-7 cell wall-binding domains. This endolysin can digest the cell walls of Streptococcus agalactiae, Streptococcus pneumoniae and Staphylococcus aureus. Turbidity reduction and plate lysis assays indicate that this peptidoglycan hydrolase also shows strong lytic activity toward Streptococcus pyogenes, Streptococcus dysgalactiae, Streptococcus uberis, Streptococcus equi, GES, and GGS. Deletion analysis on the His-tagged version of this gene further indicates that the N-terminal endopeptidase domain is minimally active in the absence of a Cpl-7 domain when lysing cells from without; however, with both Cpl-7 domains, it achieves a higher specific activity than the full length protein (on some strains) and shows weak activity against two Coagulase Negative Staphylococci, Staphylococcus hyicus and Staphylococcus xyloses.