Characterization of a novel Jumbo phage JP4 with potential to control pathogenic Escherichia coli

Amidst rising antimicrobial resistance, bacteriophage (phage) therapy has re-emerged as a pivotal weapon against multidrug-resistant pathogens. Jumbo phages, distinguished by large genomes, show particular therapeutic promise. Yet current understanding of jumbo phages is still lacking.

Phage was isolated from domestic sewage. The biological properties of JP4 was characterized via transmission electron microscopy, stability tests, one-step growth curve. The genome of JP4 were elucidated by sequencing and bioinformatics tools. Structural proteins were identified via mass spectrometry. Bactericidal and biofilm eradication activities were evaluated using bacterial turbidity measurements and crystal violet assays, respectively. Statistical significance was determined by using one-way ANOVA in GraphPad Prism.

Phage JP4 has an icosahedral head (approximately 110 nm in diameter) and a contractile tail (about 120 nm in length). JP4 possesses a linear dsDNA genome of 370,741 bp, encoding 738 proteins and 8 tRNAs. Phylogenetic analysis revealed that JP4 is a new member of the Asteriusvirus genus, and shares close evolutionary relationships with Escherichia phage UB. Additionally, mass spectrometry identified four novel structural protein encoding genes of JP4. Phage JP4 exhibited rapid infection cycle, high stability, potent in vitro bactericidal activity, and strong inhibitory effect on E. coli biofilms.

Phage JP4 is a new member of the Asteriusvirus genus. As a lytic jumbo phage with rapid bactericidal activity and strong biofilm degradation capacity, JP4 is a promising therapeutic candidate against E. coli O157:H7 infections. This study provides insights into the diversity and clinical potential of jumbo phages in combating pathogens.