Isolation and characterization of lytic bacteriophages against Escherichia coli serogroups O1, O2, and O78

The goal of this study was to isolate and characterize a complete set of phages that are active against Escherichia coliserogroups O1, O2, and O78, the main causative agents of avian colibacillosis. A mixture of E.coli (O1:K1), (O2:K1), and (O78:K80) used as host to isolate phages from wastewater and fecal samples from poultry processing plants. Eleven phages were isolated, only two of them EC-NJ4 and EC-NJ7 were selected for further characterization. EC-NJ4 and EC-NJ7 had icosaheadral heads, necks and contractile tails, with tail fibers and therefore belonged to Myoviridae, with genome sizes of 67.06 – 68.04 kb and they lysed 100% of serotype O1, O2, and O78. The two phages were resistant to pH 5-9, and phage EC-NJ7 was slightly more resistant to acid and alkali environments. It was concluded that Phage EC-NJ4 and EC-NJ7 are highly active against O1, O2, and O78 colibacillosis strains and it might be suitable candidate for phage therapy. Running title: APEC, Phages, E. coli O1, O2, O7