Characterization of phage vB_EcoP_HC25 and its therapeutic effect on chicken colibacillosis

APEC (avian pathogenic Escherichia coli) infections result in huge economic losses, the emergence of antibiotic resistance bacteria has brought enormous pressure to public health. Bacteriophage therapy has proved to be an attractive candidate for decreasing drug-resistant bacteria. In this paper, a novel Escherichia coli phage vB_EcoP_HC25 was isolated from sewage. Phage vB_EcoP_HC25 had an elongated head, and a short tail, exhibiting the typical features of the rare C3 morphotype phages. The optimal MOI of vB_EcoP_HC25 phage was 0.01, the latency of vB_EcoP_HC25 was 30 min, and approximately 60 min for the lytic phase. The lysis amount was approximately 105 PFU/cell. Phage vB_EcoP_HC25 exhibited wide pH stability (pH 5~11) and good temperature tolerance (< 60℃). In addition, the genomic analysis revealed that phage vB_EcoP_HC25 did 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 Escherichia coli in milk and chicken meat. In addition, the results of the mental state, behavior, serum inflammatory factors, and intestinal morphological analysis indicated that phage vB_EcoP_HC25 was effective to control colibacillosis in chicks infected with E. coli.