Enzymatic detergent treatment protocol that reduces protease-resistant prion protein load and infectivity from surgical-steel monofilaments contaminated with a human-derived prion strain

The unconventional nature of the infectious agent of prion diseases poses a challenge to conventional infection control methodologies. The extraneural tissue distribution of variant and sporadic Creutzfeldt-Jakob disease has increased concern regarding the risk of prion disease transmission via general surgical procedures and highlighted the need for decontamination procedures that can be incorporated into routine processing. In this study, the ability of preparations of enzymatic medical instrument cleaners to reduce the infectivity associated with a rodent-adapted strain of human prion disease, previously reported to be resistant to decontamination, was tested. Efficient degradation of the disease-associated prion protein by enzymatic cleaning preparations required high treatment temperatures (50-60 degrees C. Standard decontamination methods (1 M NaOH for 1 h or autoclaving at 134 degrees C for 18 min) reduced infectivity associated with the human-derived prion strain by less than 3 log(10) LD50. In contrast, a 30 min treatment with the optimized enzymatic cleaning preparation protocols reduced infectivity by more than 3 log(10) LD50 and when used in conjunction with autoclave cycles eliminated detectable levels of infectivity. The development of prion decontamination procedures that are compatible with routine cleaning and sterilization of medical and surgical instruments may reduce the risk of the transmission of prion disease in general surgery.