Characterization of a Multidrug-resistant Escherichia Coli Lytic Bacteriophage Isolate as a Safe Alternative to Synthetic Antibiotics

The control of pathogenic bacteria depends mainly on the use of antibiotics; however, several problems can arise due to the overuse of broad-spectrum antibiotics that destroy not only pathogens, but also natural beneficial microbes in the gut micro-flora. Furthermore, the development of antibiotic resistance poses a major challenge in clinical medicine. Therefore, there is an urgent therapeutic need to develop safe alternative bactericidal or bacteriostatic approaches that will selectively kill only pathogens without disrupting the micro-flora. One such approach is the use of bacteriophages to suppress the growth of bacterial pathogens in humans and other animals. Sewage water can be a rich source of pathogenic bacteria and their lytic phages; thus, we sampled sewage water in this study and successfully isolated an Escherichia coli strain and its lytic phage. We demonstrated that the phage could repress bacterial growth of Salmonella enterica (ATCC 14028), Klebsiella oxytoca (ATCC49131), Shigella sonnei (ATCC 25931), and E. coli (ATCC25922). The isolated phage was stable at room temperature, but survival declined with an increase in temperature to 70 °C, and complete inhibition was observed at temperatures 80 °C. In addition, the phage was stable over a pH range of 6–8, and was completely inactivated at pH 14. Keywords: bacteriophage, Escherichia coli strain M00057, EC phage, multidrug- resistance