The present invention features therapeutic bacteriophage deficient in thelysin protein ("Lys minus" phage). Lys minus bacteriophage are incapable offacilitating efficient lysis of the bacterial host since the enzymaticactivity of the lysin of the phage is needed for breaking down thepeptidoglycan layer of the bacterial cell wall. Lys minus bacteriophage retainactivity in invasion of its appropriate bacterial host, destruction of thebacterial genome, and replication, which are sufficient to inhibit bacterialgrowth and replication. Therefore, the therapeutic Lys minus phage stops thespread of infection by the bacterial pathogen without lysis of the bacterium.This approach is attractive as it also prevents the release of the phageprogeny, thus reducing or eliminating the potential for generation of immuneresponses against the phage. The incapacitated bacterial pathogen is thenremoved by the normal defense systems such as phagocytes and macrophages.
