Characterization and Utilization of Podoviridae Phages for Controlling Pathogenic Escherichia coli Serovar O168 from Ducklings in Egypt

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This study was carried out to isolate and characterize lytic bacteriophages against the multidrug resistant and pathogenic Escherichia coli serotype O168 isolated from ducklings in Egypt; and also to study efficacy of single phage and cocktail phages on In vitro inactivation of E. coli O168. One hundred and fifteen samples from ducklings, including caecal contents, skin, minced breast, gizzard, swabs from mouth, cloacae and inner surface of liver, were collected, pre-enriched in peptone water and streaked MacConkey agar, and Eosin-Methylene Blue agar. The presumptive isolates of E. coli were subjected for biochemical and serological identifications. Antimicrobial susceptibility testing was performed by the disk diffusion method. Phages against E. coli serotype O168 were isolated from sewage samples using plaque assay test. An evaluation of phages efficacy was achieved separately and in cocktail to control the most multidrug resistant serotype E. coli O168. Three different single plaques with different plaque morphologies and diameters designated as ECa1, ECb1, and ECc1 were picked and chosen for further purification, amplification and characterization. The recovered phages were belonged to the family Podoviridae. The use ofcocktail phages (ECa1/ECb1/ECc1) was significantly effective (reductions of 7.4 log CFU/ml 12hrs post treatment) than the use single phage suspensions. This study confirmed the higher efficacy of phage cocktails in controlling the infection of ducklings with multidrug resistant E. coli O168. These phages will reduce mortality in ducklings, and also protect human health from adverse side effects of antibiotic residues.

Duckmeat is the most popular type of food in Egypt and various parts of the world. Ducks are excellent sources of animal-derived high quality proteins that contain essential and nonessential amino acids. Pathogenic Escherichia coli infecting poultry is the causative agent of colibacillosis, one of the most important causes of economic losses in industry of poultry worldwide. In Egypt, five serotypes of E. coli (O86, O127, O114, O26 and O78) were identified from gizzard, heart, spleen and muscles of ducks. Some bacterial diseases such as salmonellosis, colibacillosis, and pasteurelliosis infect a variety of organ systems with involving the alimentary tract. Escherichia coli is a food borne pathogen, and has a public health concern. Recently, there has been attention that some multidrug resistant E. coli have represented a worldwide multiple food borne disease disorders related to the contaminated food consumption. Also, the misuse of antimicrobial agents in poultry production for growth promotion and treatment purposes increases the major interest for the multidrug resistance that are frequently seen among serovars of E. coli and Salmonella. Antimicrobial-resistant food borne pathogens is recognized as an essential public health in the developing countries and this resistance reduces the therapeutic options for treatment of human salmonellosis.