In order to the phage therapy for Clostridium perfringens(Cp),Cp was used as the host bacterium to screen specific phages from sewage collected from a large-scale beef cattle farm in a region of Shandong Province.Transmission electron microscopy was utilized to observe the mor-phological structure of the phages.Their characteristics were analyzed through the optimal multi-plicity of infection(MOI),host range,one-step growth curve,and antibacterial experiments.The re-sults showed that one phage was successfully isolated from 18 sewage samples.The plaque was transparent without a halo,exhibiting a broad host range and no lytic reaction with other tested bacteria.The optimal MOI was 0.1,and the phage entered the burst phase in 30 min.The phage maintained high titers at pH3-13 and remained active after treatment at 60℃ for 60 min,demon-strating good stability.Mice were infected with CP and treated with bacteriophage.Animal experi-ments showed that the isolated bacteriophage had a significant inhibitory effect on CP.The results indicated that the isolated phage,designated vB-CpP-Bp7,was a virulent phage with excellent lytic capability,acid-base stability,and thermal stability,laying a foundation for further application of this phage in phage therapy.

In order to the phage therapy for Clostridium perfringens(Cp),Cp was used as the host bacterium to screen specific phages from sewage collected from a large-scale beef cattle farm in a region of Shandong Province.Transmission electron microscopy was utilized to observe the mor-phological structure of the phages.Their characteristics were analyzed through the optimal multi-plicity of infection(MOI),host range,one-step growth curve,and antibacterial experiments.The re-sults showed that one phage was successfully isolated from 18 sewage samples.The plaque was transparent without a halo,exhibiting a broad host range and no lytic reaction with other tested bacteria.The optimal MOI was 0.1,and the phage entered the burst phase in 30 min.The phage maintained high titers at pH3-13 and remained active after treatment at 60℃ for 60 min,demon-strating good stability.Mice were infected with CP and treated with bacteriophage.Animal experi-ments showed that the isolated bacteriophage had a significant inhibitory effect on CP.The results indicated that the isolated phage,designated vB-CpP-Bp7,was a virulent phage with excellent lytic capability,acid-base stability,and thermal stability,laying a foundation for further application of this phage in phage therapy.