Effects of prophylactic administration of bacteriophages to immunosuppressed mice infected with Staphylococcus aureus

High numbers of bacterial colony-forming units in the organs as well as elevated tumor necrosis factor and interleukin-6 serum concentrations in CP-treated and S. aureus-infected mice were significantly lowered upon application of phages. The phages markedly increased the percentage of circulating neutrophils and immature cells from the myelocytic and lymphocytic lineages in CP-treated, S. aureus-infected mice as well as of myelocytes and immature neutrophils in the bone marrow. In addition, phages stimulated in such mice generation of specific agglutinins against S. aureus.Application of specific phages to immunosuppressed mice prior to infection with S. aureus proved very effective, suggesting a potential benefit of phage therapy in immunocompromised patients experiencing bacterial infections.Phage therapy offers an excellent alternative to antibiotic therapy of bacterial infections (reviewed by [1]). Despite obvious efficacy in curing antibiotic-resistant infections it is still considered as "experimental" although it used to be a routine therapeutic approach to treat bacterial infections before introduction of antibiotics into therapy in the first half of the XXth century. In contrast to antibiotics, which usually exhibit suppressive actions in relation to the immune response and deplete physiological intestinal microflora [2,3], the phage lytic action is highly selective. Moreover, phages demonstrate some bystander effects, beneficial to the function of the immune system such as: normalization of cytokine production by blood cells isolated from patients [4], acceleration of the neutrophil turnover [5], and inhibition of both bacteria- and LPS-induced respiratory burst by human blood phagocytes [6,7]. A discovery that phages may limit metastasis of B16 melanoma in mice [8] suggests a benefit of phage therapy in patients with malignant diseases.Effectiveness of phage therapy may be, however, limited by several factors. Phage-resistant mutants has been observed in