Characterisation of phage vB_Ec_DUEC01: A lytic Kagunavirus for multidrug-resistant Escherichia coli

Multi-drug resistant (MDR) Escherichia coli has become one of the significant global health concerns, and this demands the development of alternative strategies for antimicrobials. The present study describes the isolation and characterisation of bacteriophage vB_Ec_DUEC01- a virulent member of the class Caudoviricetes-which could serve as a potential biocontrol agent against MDR E. coli. Electron microscopy showed an icosahedral capsid and a long, non-contractile tail. The one-step growth curve resulted in a latent period of 20 min with a high burst size of 97 PFU per infected cell. Moreover, the phage showed reasonable stability over a pH range of 3.0-12.0 and at moderate temperatures of 20 °C-40 °C. Whole-genome sequencing revealed a genome of 43,949 bp encoding 77 open-reading frames (ORFs), encoding structural, packaging, DNA replication and metabolism, and lysis proteins. No lysogeny-related, antibiotic resistance, or virulence factor genes were found. Phylogenetic analysis placed the phage in the Kagunavirus genus, with closely related therapeutically relevant phages. Results suggest that vB_Ec_DUEC01 is effective, genetically safe, and stable; therefore, it is a preliminary good candidate for application as a biocontrol agent against MDR E. coli. Further, host-range and in vivo efficacy studies are necessary to develop this application in antimicrobial therapy.