Characterization of a newly isolated phage infecting pathogenic Escherichia coli and analysis of its mosaic structural genes

The outbreak of multidrug-resistant pathogenic bacteria made the discovery of novel control strategies necessary. Phages have regained attention for their specific lytic activity against pathogenic bacterium. A newly isolated phage infecting the clinical Escherichia coli isolates, including several multidrug-resistant strains, was isolated, and this phage showed high control effects against the tested pathogenic E. coli strains. Host range analysis revealed that although the phage exhibited broad lytic spectrum against the tested E. coli strains, it could not lyse strains from the other species. Comparative genomic analysis showed that phages had undergone at least three genome recombination events during the evolutionary process at the position of the three phage tail genes, which was reported to be associated with the host range determination of the phage. The recombinant tail proteins contained functional domains that were highly similar with genes of the Salmonella phage and genes of Pseudomonas and Neisseria. The findings of this study not only provide resources for developing phage therapy against E. coli, but also showed the highly variable genome structure of the phage.