Whole-Genome Sequencing and Functional Characterization of a Novel Kuravirus Bacteriophage with Antibiofilm Activity Against Multidrug-Resistant Avian Pathogenic Escherichia coli.

Avian pathogenic Escherichia coli (APEC) infections cause substantial economic losses in the poultry industry, primarily due to high mortality rates, reduced productivity, and increased treatment costs. With the emergence of antibiotic-resistant APEC strains, including multidrug-resistant (MDR) variants, alternative therapeutic strategies have gained increasing attention. This study reports the isolation and characterization of an Escherichia phage, vB_EcoG_APECPW12 (phage vAPECPW12), which specifically targets MDR APEC. Both antibacterial and antibiofilm activities of the phage were evaluated. Phage vAPECPW12 produced small plaques with halos and exhibited strong lytic activity against MDR APEC. Whole-genome sequencing revealed a genome size of 77,812 base pairs with 123 open reading frames. No tRNA, antibiotic-resistant, or lysogenic genes were identified. Phylogenetic analysis and genome comparison suggest that phage vAPECPW12 is a novel member of the genus Kuravirus within the Gordonclarkvirinae family. It also demonstrated good stability across a range of temperatures and pH levels and remained viable after exposure to UV radiation. Phage vAPECPW12 showed a high adsorption rate, a short latent period of 10 min, and a burst size of 258 plaque-forming units per cell. A depolymerase domain was identified in the genome, prompting investigation of its antibiofilm efficacy. Results showed that vAPECPW12 significantly inhibited biofilm formation and removed preformed biofilms, indicating its potential as an alternative antimicrobial agent for controlling MDR APEC and their biofilms in poultry farming.