NR ARFB
AU Roth,K.; Yan,Z.; Heeg,P.; Gaedt,S.; Pfaff,E.; Stitz,L.; Zenner,H.P.; Mauz,P.S.
TI Infectivity of prion protein bound to stainless steel wires: a new technique for testing decontamination or inactivation procedures of TSE by radioactive labelling
QU TSE-Forum, 4. Kongress - Nationale TSE-Forschungsplattform, Düsseldorf 28.10.-29.10.2004, Poster INAK-04
PT Konferenz-Poster
AB
Objective
Establish a transmissible spongiform encephalopathy animal model using hamsters and steel wires contaminated with infectious brain materials as transfer vehicles.
Based on this model to test decontamination procedures against the infectious prion proteins on the steel wires as a near real situation bioassay. A further step is the development of an innovative test procedure based on radioactive marked prion proteins, to substitute the bioassay.
Design
Infectious brain materials are given to healthy hamster intracerebrally either as suspension or as dried materials on the surface of steel wires. The animal are to be under observation for 18 months. During this period animals showing definitive clinical signs are to be euthanized.
Decontamination studies were performed by reprocessing of contaminated steel wires with different chemical agents and sterilization procedures before implantation of the wire.
Additionally prion proteins have been radioactive labelled with Tc 99. Steel wires have been incubated and processed. Radiation have been measured after contamination and after reprocessing.
Results
hamster adapted pathological prion proteins are found to be able to bind to the steel wire and cause disease after the contaminated wires are implanted in the brain of hamsters. When the contaminated wires were treated with different reprocessing procedures before implantation infectivity was reduced which was manifested directly by prolonged survival time of the test animals. These results show that this model can be used as a bioassay to validate reprocessing procedures for surgical instruments.
Radiation could be detected after labelling and washing with PBS.
Conclusions
the present study provided us with the following information:
* Treatment of wires with an alkaline detergent at pH value 11 shows significant reduction of infectivity, independent of the procedure (disinfection or sterilization) that follows.
* Steam sterilization at 134° for 18 minutes in combination with initial enzymatic cleaning does not result in the inactivation of the prion proteins.
* Steam sterilization at 134° for 18 minutes without initial enzymatic treatment results in much higher survival rates of the animals.
* Sterilization with the Hydrogen peroxide gas plasma sterilizer (Sterrad system) seems to have similar effect as steam sterilization.
Outlook
Radioactive labelling of prion proteins seems to be successful. This technique is in the process of testing in bioassay. This method should give information about whether the prion protein bounded to the steel surface is removed or inactivated by the process employed.
AD K. Roth, Z. Yan, SMP GmbH, Tübingen; S. Gaedt, H.P. Zenner, P.S. Mauz, Universitätsklinik HNO Tübingen; E. Pfaff, L. Stitz, Friedrich-Loeffler-Institut, Tübingen; P. Heeg, Universitätsklinik Tübingen - Mikrobiologie und Klinikhygiene
SP englisch
PO Deutschland
OR Tagungsband