title: Prevalence of Salmonella infecting bacteriophages associated with Ontario pig farms and the holding area of a high capacity pork processing facility.
abstract: BACKGROUND
  There is interest in applying bacteriophages to control Salmonella in pig production and pork processing. The following reports on the prevalence of Salmonella infecting bacteriophages within Ontario pig farms and associated with the holding area of a pork slaughterhouse.
  
  
  RESULTS
  Salmonella infecting bacteriophages were present in 30 and 28 of the effluent manure samples collected from 36 farms using S. Typhimurium DT104 or S. Heidelberg as host cell respectively. Bacteriophages were recovered in 95-100% of the 48 samples taken from holding pens within a high capacity slaughterhouse over a 12 month period. Bacteriophages isolated from farms exhibited similar host ranges which differed to that of slaughterhouse isolates. Salmonella (n = 21) from the slaughterhouse were susceptible to the endogenous bacteriophages. Despite being susceptible to the resident phages, the Salmonella populations were found to be genetically stable with the same genotypes being recovered over successive visits. Salmonella isolated from the farms were frequently resistant to the endogenous phages.
  
  
  CONCLUSIONS
  Bacteriophages are prevalent in the pig slaughterhouse environment although they do not have a significant impact on the genetic structure of Salmonella populations. However, there was evidence that the Salmonella population structure on farms is influenced by the presence of infecting phages.
authors.affiliation: Department of Food Science, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Sunan
authors.initials: S
authors.lastname: Wang
authors.forename: Weikang
authors.initials: W
authors.lastname: Zhao
authors.forename: Asad
authors.initials: A
authors.lastname: Raza
authors.forename: Robert
authors.initials: R
authors.lastname: Friendship
authors.forename: Roger
authors.initials: R
authors.lastname: Johnson
authors.forename: Magdalena
authors.initials: M
authors.lastname: Kostrzynska
authors.forename: Keith
authors.initials: K
authors.lastname: Warriner
mesh_terms: D000003:Abattoirs; D000822:Animal Husbandry; D000818:Animals; D001433:Bacteriolysis; D001434:Bacteriophage Typing / Q000662:veterinary; D005243:Feces / Q000382:microbiology / Q000821:virology; D005838:Genotype; D054884:Host-Pathogen Interactions; D008460:Meat / Q000382:microbiology*; D009864:Ontario; D015995:Prevalence; D025341:Principal Component Analysis; D012475:Salmonella / Q000235:genetics / Q000302:isolation & purification* / Q000821:virology*; D012481:Salmonella Infections, Animal / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control / Q000821:virology; D012483:Salmonella Phages / Q000145:classification / Q000302:isolation & purification* / Q000502:physiology; D034421:Sus scrofa; D013997:Time Factors