Lysostaphin is an enzyme that selectively cuts through the cell walls of S. aureus. Several features of lysostaphin make its mechanism of action unique. Standard antibiotics only kill staphylococci during growth phases. Lysostaphin is able to disintegrate S. aureus cells at any stage of the growth cycle, even after the cells are dead. Because of the unique presence of pentaglycine bridges in S. aureus, lysostaphin is a uniquely specific agent that is effective against different varieties of S. aureus, irrespective of their resistance to conventional antibiotics, including methicillin and vancomycin.

Lysostaphin has completed Phase I/II clinical trials in adults.