Decontamination of surgical instruments from prions. II. In vivo findings with a model system for testing the removal of scrapie infectivity from steel surfaces

Abstract

The unusual resistance of agents causing transmissible spongiform encephalopathies (TSEs) to chemical or thermal inactivation requires special decontamination procedures in order to prevent accidental transmission of these pathogens by surgical instruments. In the search for effective, instrument-compatible and routinely applicable decontamination procedures, a previous study [Lemmer, K., Mielke, M., . J Gen Virol 85, 3805-3816] identified promising reagents in an in vitro carrier assay using steel wires contaminated with the diseaseassociated prion protein, PrP Sc . In the follow-up study presented here, these reagents were validated for their decontamination potential in vivo. Steel wires initially loaded with ¢3¾10 5 LD 50 of 263K scrapie infectivity were implanted into the brains of hamsters after treatment for decontamination and subsequently monitored for their potential to trigger clinical disease or subclinical cerebral PrP Sc deposition within an observation period of 500 days. It was found that routinely usable reagents such as a commercially available alkaline cleaner (pH 12.2) applied for 1 h at 23 6C or for 10 min at 55 6C and a mixture of 0.2 % SDS and 0.3 % NaOH (pH 12.8) applied for 5 or 10 min at 23 6C achieved removal of 263K scrapie infectivity below the threshold of detection (titre reduction of ¢5.5 log 10 units). The increasing use during the past few years of similar model systems by different research groups will facilitate comparison and integration of findings on the decontamination of steel surfaces from prions. Methods identified as highly effective in the 263K steel wire model need to be validated for human TSE agents on different types of instrument surfaces.

Sodium hydroxide based non-detergent decellularizing solution for rat lung

“…Moreover, high alkaline water (pH11.9 or more) can inactivate transmissible spongiform encephalopathies, the pathogens responsible for prion diseases. Since prion infection is a potential risk when using tissue engineered organs, 20 to ensure safety from prion disease, NaOH based decellularization solution has a significant advantage in regard to prion inactivation of the biomaterials. 21 , 22 …”

Infrared Microspectroscopy Detects Protein Misfolding Cyclic Amplification (PMCA)-induced Conformational Alterations in Hamster Scrapie Progeny Seeds

“…Paraffin-embedded Tissue (PET) Blotting-PET blotting was performed as described previously (25) with midsagittal brain sections.…”

Towards further reduction and replacement of animal bioassays in prion research by cell and protein misfolding cyclic amplification assays

“…A titre analysis of these results performed in analogy to the method of Spearman-Kärber revealed that 1.0 Â 10 27.0 g (standard deviation: 0.6 logarithmic 10 units) of the 263K stock (from previous titrations in hamster bioassays known to carry about 1 Â 10 2 intracerebral ID 50 ) contained one CCID 50 in the cell assay performed with a cultivation period of 40 DPE. 25,28 . ...........................................................................................................................................…”