Submitted to: Mississippi Water Resources Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 26, 2005
Publication Date: April 26, 2005
Citation: Mclaughlin, M.R., El Balaa, M.F., Rowe, D.E., Sims, J., Andersland, J., King, R. 2005. Isolation of salmonella bacteriophages from swine waste lagoons [abstract]. Mississippi Water Resources Research Conference Abstracts. p. 20.
Lagoons on nine Mississippi hog farms were tested for the presence of lytic Salmonella-specific phages. Lytic phages are viruses that infect and kill bacteria. Salmonella-killing phages were isolated using an enrichment method or directly from clarified filtered effluent. Enrichment samples were treated to remove bacteria, then mixed with nutrient broth containing a Salmonella cocktail (serotypes Typhimurium and Enteritidis) to favor growth of Salmonella phages. After overnight incubation, Salmonella were killed and enriched samples tested by plaque assay against individual Salmonella isolates. Enrichment produced lytic phage titers of 2.9 x 108 to 2.1 x 109 plaque forming units (pfu) per ml. In direct isolation, effluent was clarified by centrifugation and filtration, then used in plaque assays against host isolates of serotypes Typhimurium, Enteritidis, Agona, Michigan, Montevideo and Gaminara. Phages were recovered by the direct method for all serotypes except Gaminara, but plaque formation varied among host isolates and lagoons. The most sensitive host for direct isolation of phages was S. typhimurium ATCC 13311. The direct method was used with ATCC 13311 to estimate phage titers among the lagoons, which ranged from 12-148 pfu per ml. Host ranges of phages from enriched samples, showed all were specific for S. enteritidis and S. typhimurium and none produced plaques on lagoon isolates of Citrobacter youngae, Escherichia coli, E. fergusonii, Proteus mirabilis, Providencia rettgeri or Serratia marcescens. Electron microscopy (EM) of enrichment phages showed all were 50 nm diameter icosahedrons with tail spikes. These phages have potential use in the identification, characterization and biocontrol of Salmonella.