Background: Pseudomonas aeruginosa  is an important nosocomial infectious bacterium, more and more multidrug resistant P. aeruginosa  have been isolated and posed severe challenges to clinical antibiotic treatment, bringing additional morbidity, mortality, and economic burden. Bacteriophages can lyse bacteria specificity and are feasible alternatives to antibiotics.
Methods: A Pseudomonas aeruginosa -infecting phage vB_PaeP_PA01EW was isolated. Phage plaque assays, transmission electron microscopy, host-range determination, infection assay analyses, whole-genome sequencing and annotation were performed for the phage. Mice pneumonia model using liquid aerosol-exposure Pseudomonas aeruginosa  was established, and phage therapy was evaluated.
Results: vB_PaeP_PA01EW belongs to the family Podoviridae  according to transmission electron microscopy and was identified as a Luz24likevirus  according to the genome analysis. For the phage therapy, compared with the bacteria-infected group, the phage-rescue group has some characteristics. First, adventitial edema and diffuse infiltration of inflammatory cells in tissues were alleviated, Second, bronchial epithelial cell proliferation was reduced. Third, the bacterial burden was significantly decreased.
Conclusion: This study provided data support and theoretical basis for the clinical application of bacteriophages. It has important guiding significance and reference value for the application of bacteriophage therapy of other pathogenic bacteria.
Keywords: P. aeruginosa , bacteriophage, vB_PaeP_PA01EW, aerosol-exposure