Molecular and biological characterization of a newly discovered Kayfunavirus bacteriophage targeting multidrug-resistant Escherichia coli from swine feces

Multidrug-resistant (MDR) Escherichia coli infections and their biofilms in swine and swine farms are a major concern due to their impact on animal health, economic losses, and the spread of antibiotic resistance. There is also increasing concern about the potential transmission of antibiotic resistance from animals to humans. To address these issues, alternative strategies to control E. coli infections are being explored, with bacteriophage (phage) therapy emerging as a promising approach. In this study, Escherichia phage vECPPW10 was isolated and characterized. Genomic analysis revealed a 40,621-base-pair linear double-stranded DNA genome encoding 48 coding sequences organized into four functional modules: phage morphology, DNA replication, DNA packaging, and host cell lysis. No temperate lifestyle-related genes, bacterial, or antimicrobial resistance genes were detected, indicating the genomic safety of the phage. Phylogenetic and PhageCloud analyses classified vECPPW10 as a newly discovered species within the genus Kayfunavirus and the subfamily Studiervirinae. Biologically, the phage demonstrated a moderate adsorption rate, short latent period, moderate burst size, and strong lytic efficiency. At a low MOI, the phage completely suppressed MDR E. coli growth within 1 h. Scanning electron microscopy revealed phage-induced structural damage to bacterial cells, leading to cell death. The presence of halos around plaques suggested depolymerase activity and corresponding antibiofilm potential. Consistent with these observations, phage vECPPW10 inhibited biofilm formation and eradicated preformed biofilms. Overall, these findings indicated that phage vECPPW10 is a strong candidate for controlling MDR E. coli infections and biofilms in swine and swine farms.