Unveiling the Potential of Enzymatic Detergents to Deactivate Infectious Prions

When infectious misfolded proteins self-propagate, they cause transmissible spongiform encephalopathies (TSEs) or prion diseases. TSEs are rare, progressive neurodegenerative diseases with long incubation times and are always fatal. Iatrogenic transmission of these diseases is a major concern for human health, and existing methods of decontamination are either ineffective or require caustic chemical treatment followed by extended steam sterilization cycles. Research was undertaken to explore using enzymatic detergents to decontaminate prion-laden surgical devices, equipment, and stainless-steel tools using existing healthcare facility protocols, including cleaning followed by steam or low-temperature sterilization. Several formulations of enzymatic detergents were used to clean stainless steel wires contaminated with infected hamster brain homogenate. Buffering the solutions to achieve a final pH between 8.5 and 9 when diluted, followed by sonication at 45 to 60°C, was effective in rendering prions undetectable in Western blot images. Subsequent sterilization in an autoclave improved the results, causing further prion degradation. Protein misfolding cyclic amplification showed that adding a four-minute prevacuum auto-clave cycle produced a less than 5-log to 6-log reduction in infectious prion proteins using a multienzymatic detergent and a 6-log reduction using a protease enzyme detergent. Increasing the autoclave cycle to 18 minutes generated a consistent 6-log reduction for both formulations, which is the accepted benchmark for effective sterilization.