title: Evaluation of a combinatorial approach to prion inactivation using an oxidizing agent, SDS, and proteinase K.
abstract: BACKGROUND
  Prions demonstrate an unusual resistance to methods effective at inactivating conventional microorganisms. This has resulted in a very tangible and difficult infection control challenge to the medical and veterinary communities, as well as animal agriculture and related industries. Currently accepted practices of harsh chemical treatments such as prolonged exposure to sodium hydroxide or sodium hypochlorite, or autoclaving are not suitable in many situations. Less caustic and more readily applicable treatments to contaminated environments are therefore desirable. We recently demonstrated that exposure of the RML scrapie agent to a commercial product containing sodium percarbonate (SPC-P) with or without sodium dodecyl sulfate (SDS) rendered PrP(Sc) sensitive to proteinase K (PK), but did not eliminate infectivity. The current study was designed to evaluate the efficacy of a combinatorial approach to inactivating prions by exposing RML-positive brain homogenate to SPC-P and SDS followed by PK. Treated samples were evaluated for PrP(Sc)-immunoreactivity by western blot, and residual infectivity by mouse bioassay.
  
  
  RESULTS
  Treatment of infected brain homogenate with SPC-P and SDS followed by PK exposure resulted in a 4-5 log10 reduction in infectivity when bioassayed in tga20 mice.
  
  
  CONCLUSIONS
  This study demonstrates that exposure of the RML scrapie agent to SPC-P and SDS followed by PK markedly reduces, but does not eliminate infectivity. The results of this study encourage further investigation into whether consecutive or concomitant exposure to sodium percarbonate, SDS, and a protease may serve as a viable and non-caustic option for prion inactivation.
authors.affiliation: Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, USDA, 1920 Dayton Ave, Ames, IA 50010, USA.
authors.forename: Jodi D
authors.initials: JD
authors.lastname: Smith
authors.forename: Eric M
authors.initials: EM
authors.lastname: Nicholson
authors.forename: Justin J
authors.initials: JJ
authors.lastname: Greenlee
mesh_terms: D000818:Animals; D001681:Biological Assay; D015153:Blotting, Western; D019286:Endopeptidase K / Q000627:therapeutic use*; D051379:Mice; D016877:Oxidants / Q000627:therapeutic use*; D018620:PrPSc Proteins / Q000187:drug effects; D011328:Prions / Q000187:drug effects*; D012608:Scrapie / Q000188:drug therapy; D012967:Sodium Dodecyl Sulfate / Q000627:therapeutic use*
chemical_list: D016877:Oxidants; D018620:PrPSc Proteins; D011328:Prions; D012967:Sodium Dodecyl Sulfate; D019286:Endopeptidase K