Isolation and characterization of bacteriophages for avian pathogenic E. coli strains

Aims: To isolate and characterize bacteriophages, and to evaluate its lytic performance against avian pathogenic Escherichia coli (APEC) strains with high patterns of antibiotic resistance, in order to select phages for a therapeutic product to treat colibacillosis in chickens. Methods and Results: Bacteriophages were isolated from poultry sewage and tested against 148 O-serotyped APEC strains. The morphological characterization of the bacteriophages was made by transmission electronic microscopy (TEM) observations and the genetic comparison between bacteriophages DNA was performed by restriction fragment length polymorphism (RFLP) patterns. Results showed that 70·5% of the tested E. coli strains were sensitive to a combination of three of the five isolated phages, that seemed to be virulent and taxonomically belong to the Caudovirales order. Two of them look like 16–19, T4-like phages (Myoviridae) and the third is a T1-like phage and belongs to Syphoviridae family. All of them are genetically different. Conclusions: It was possible to obtain a combination of three different lytic bacteriophages with broad lytic spectra against the most prevalent O-serotypes of APEC. Significance and Impact of the Study: Data reported in this study, presents an in vitro well studied phage product to be used as antimicrobial agent to treat colibacillosis in poultry industry.Fundação para a Ciência e a Tecnologia (FCT