Automated decontamination of surface-adherent prions

At present there is no routinely available decontamination procedure in washer-disinfectors to allow the reliable inactivation and/or elimination of prions present on reusable surgical instruments. This means that is not possible to provide assurance for preventing iatrogenic transmission of prion diseases. We need effective procedures in prion decontamination that can be integrated into the usual routine of reprocessing surgical instruments. This article reports on the evaluation of an automated process designed to decontaminate prions in washer-disinfectors using a quantitative, highly sensitive in vivo assay for surface-adherent 22L prions. The automated process showed great advantages when compared with conventional alkaline cleaning. In contrast, the new process was as effective as autoclaving at 134 degrees C for 2h and left no detectable prion infectivity, even for heavily contaminated surfaces. This indicates a reduction of surface-adherent prion infectivity of >7 log units. Due to its compatibility with even delicate surgical instruments, the process can be integrated into the large scale reprocessing of instruments in a central sterile supply department. The system could potentially make an important contribution to the prevention of iatrogenic transmission of prions.