title: Characterization of bacteriophages with a lytic effect on various  Salmonella  serotypes and  Escherichia coli  O157:H7.
abstract: Four phages isolated from cattle and poultry feces were analyzed for their ability to lyse Salmonella serotypes and Escherichia coli O157:H7. The phage one-step growth curves, morphology, and genetic characteristics were determined. All phages showed a lytic effect on various Salmonella serotypes and E. coli O157:H7, which lysed at least 70% of the 234 strains tested. The phages had latent periods ranging from 10 to 15 min and generation times of 30 to 45 min, while burst size fluctuated between 154 and 426 PFU/cell. Phages morphology showed isometric and elongated heads and rigid contractile tails, consistent with morphology of the Myoviridae family. Phages' DNA dendrograms showed a distinctive RFLP when digested by HindIII and EcoRV, and SDS-PAGE profile showed distinctive proteins expression as well. In vitro phage challenge showed a total reduction of E. coli O157:H7, Salmonella Typhimurium and Saintpaul counts at 2 h, whereas for Salmonella Montevideo a reduction and retardation growth, at a multiplicity of infection (MOI) of 100, was observed; however, under a MOI of 10 000, no viable cells were detected after 4 h. The wide host ranges of these phages suggested they could be used for simultaneous biocontrol of some Salmonella serotypes and E. coli O157:H7.
authors.affiliation: a Laboratorio de Microbiología Ambiental y de Alimentos, Centro de Investigación en Alimentación y Desarrollo A.C. Carretera a Eldorado Km. 5.5, Campo El Diez, Culiacán, P.A. 32-A, 80129, Sinaloa, México.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: López-Cuevas
authors.forename: Nohelia
authors.initials: N
authors.lastname: Castro-Del Campo
authors.forename: Josefina
authors.initials: J
authors.lastname: León-Félix
authors.forename: Arturo
authors.initials: A
authors.lastname: González-Robles
authors.forename: Cristóbal
authors.initials: C
authors.lastname: Chaidez
mesh_terms: D000818:Animals; D001435:Bacteriophages / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology* / Q000648:ultrastructure; D002417:Cattle; D004262:DNA Restriction Enzymes; D004279:DNA, Viral / Q000235:genetics; D019453:Escherichia coli O157 / Q000821:virology*; D005243:Feces / Q000821:virology; D058507:Host Specificity / Q000502:physiology; D012150:Polymorphism, Restriction Fragment Length; D011200:Poultry / Q000821:virology; D012475:Salmonella / Q000821:virology*
chemical_list: D004279:DNA, Viral; D004262:DNA Restriction Enzymes