title: Isolation and characterization of nine bacteriophages that lyse O149 enterotoxigenic Escherichia coli.
abstract: The goal of this study was to isolate and characterize phages that might be used in prevention and treatment of porcine post-weaning diarrhea due to O149 enterotoxigenic E. coli (ETEC). Serotype O149:H10:F4 was especially targeted because this is the dominant ETEC serotype. Mixtures of 10 strains of O149:H10:F4 ETEC and of 10 O149:H43:F4 ETEC were used as hosts for isolation of phages in sewage from 38 Ontario pig farms. Six phages (GJ1-GJ6) that lysed O149:H10:F4 ETEC and three (GJ7-GJ9) that lysed O149:H43:F4 ETEC were isolated. All phages produced large, clear plaques. All nine phages had necks and contractile tails and therefore belonged to the Myoviridae. Their estimated genome sizes were 48.3-50.7kb and their restriction enzyme fragments suggested that they were closely related. Phages GJ1-GJ6 lysed 99-100% of 85 O149:H10:F4 ETEC, 0-12% of 42 O149:H43:F4 ETEC, 3-35% of 37 non-O149 porcine ETEC, and 6-68% of the 72 strains of the ECOR collection. Phages GJ7-GJ9 lysed 86-98% of the O149:H43:F4 ETEC, 2-53% of the O149:H10:F4 ETEC, and 24-41% of the non-O149 porcine ETEC. Titres of the nine phages were unaffected by exposure for 16h to pH 5-9. Among phages GJ1-GJ6, resistance of O149:H10:F4 ETEC to one phage was generally not accompanied by resistance to other phages. It is concluded that the nine phages are suitable candidates for prophylaxis and therapy of porcine post-weaning diarrhea due to O149 ETEC.
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada. njamallu@uoguelph.ca
authors.forename: Nidham
authors.initials: N
authors.lastname: Jamalludeen
authors.forename: Roger P
authors.initials: RP
authors.lastname: Johnson
authors.forename: Robert
authors.initials: R
authors.lastname: Friendship
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Kropinski
authors.forename: Erika J
authors.initials: EJ
authors.lastname: Lingohr
authors.forename: Carlton L
authors.initials: CL
authors.lastname: Gyles
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D003090:Coliphages / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification* / Q000648:ultrastructure; D003967:Diarrhea / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D054307:Enterotoxigenic Escherichia coli / Q000145:classification / Q000821:virology*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D008242:Lysogeny; D008854:Microscopy, Electron / Q000662:veterinary; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000517:prevention & control; D014774:Virulence; D014886:Weaning