Characterization of phage vB_EcoP_HC25 and its therapeutic effect on chicken colibacillosis

Bacteriophage therapy has proved to be an attractive candidate for decreasing drug-resistant bacteria. In this study, a novel E. coli phage vB_EcoP_HC25 was isolated from sewage. Phage vB_EcoP_HC25 has an elongated head and a short tail, exhibiting the typical features of the rare C3 morphotype. The burst size was approximately 10⁵ PFU/cell. Phage vB_EcoP_HC25 exhibited good pH range (pH 5-11) and temperature tolerance (<60 °C). The genomic analysis revealed that phage vB_EcoP_HC25 does not carry any virulence factor genes or antibiotic resistance genes. Moreover, it was found that vB_EcoP_HC25 is a promising candidate phage for biocontrol against antibiotic-resistant E. coli in milk and chicken meat. In addition, the results of the mental state, behavior, serum inflammatory factors, and intestinal morphology analyses indicated that phage vB_EcoP_HC25 was effective to control colibacillosis in chicks infected with E. coli.