Isolation and characterization of ɸEcM-vB1 bacteriophage targeting multidrug-resistant Escherichia coli

Abstract Multidrug resistance in Escherichia coli has become a concerning issue for humans worldwide. Currently, scientists are considering the use of bacteriophages in medicine as a promising alternative to antibiotics. The aim of this study was to screen for, isolate, and characterize a novel bacteriophage with confirmed lytic activity against multidrug-resistant (MDR) E. coli. A clinical MDR E. coli strain was selected among 65 isolates and identified by the VITEK2 system, and the disc diffusion method was utilized to evaluate the antibiotic sensitivity profile. A bacteriophage, designated ɸEcM-vB1, was isolated from sewage water via the enrichment method and double agar overlay technique. The lysis profile of the isolated phage against MDR E. coli was evaluated by a spot test. Transmission electron microscope was used to determine phage morphology. The growth kinetics (latent period and burst size), genomic analysis and total protein content were determined. ɸEcM-vB1 bacteriophage exhibited high lytic activity against different MDR E. coli isolates and maintained relatively high activity under broad environmental conditions of temperature (40–60°C) and in a wide pH range (3–11). It belongs to the Myoviridae family of the caudovirales order. Single-step growth curve analysis revealed that the latent period of our phage was 10 minutes, and its average burst size was 271.72 pfu/cell. Genomic analysis revealed that ɸEcM-vB1 contains dsDNA, which is susceptible to digestion by EcoRI. Ten structural proteins were detected by SDS‒PAGE. ɸEcM-vB1 is considered a promising candidate for phage therapy applications.