The present invention provides a method for reducing the risk of bacterial
infection or sepsis in a susceptible patient by treating the susceptible
patient with a pharmaceutical composition containing bacteriophage of one
or more strains which produce lytic infections in pathogenic bacteria.
Preferably, treatment of the patient reduces the level of colonization
with pathogenic bacteria susceptible to the bacteriophage by at least one
log. In a typical embodiment, the susceptible patient is an
immunocompromised patient selected from the group consisting of leukemia
patients, lymphoma patients, carcinoma patients, sarcoma patients,
allogeneic transplant patients, congenital or acquired immunodeficiency
patients, cystic fibrosis patients, and AIDS patients. In a preferred
mode, the patients treated by this method are colonized with the
pathogenic bacteria subject to infection by said bacteriophage.