Elimination of transmissible spongiform encephalopathy infectivity and decontamination of surgical instruments by using radio-frequency gas-plasma treatment

Abstract

It has now been established that transmissible spongiform encephalopathy (TSE) infectivity, which is highly resistant to conventional methods of deactivation, can be transmitted iatrogenically by contaminated stainless steel. It is important that new methods are evaluated for effective removal of protein residues from surgical instruments. Here, radio-frequency (RF) gas-plasma treatment was investigated as a method of removing both the protein debris and TSE infectivity. Stainless-steel spheres contaminated with the 263K strain of scrapie and a variety of used surgical instruments, which had been cleaned by a hospital sterile-services department, were examined both before and after treatment by RF gas plasma, using scanning electron microscopy and energy-dispersive X-ray spectroscopic analysis. Transmission of scrapie from the contaminated spheres was examined in hamsters by the peripheral route of infection. RF gas-plasma treatment effectively removed residual organic residues on reprocessed surgical instruments and gross contamination both from orthopaedic blades and from the experimentally contaminated spheres. In vivo testing showed that RF gas-plasma treatment of scrapie-infected spheres eliminated transmission of infectivity. The infectivity of the TSE agent adsorbed on metal spheres could be removed effectively by gas-plasma cleaning with argon/oxygen mixtures. This treatment can effectively remove 'stubborn' residual contamination on surgical instruments.

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

“…Similar model systems have been increasingly employed during the past few years by different research groups (Yan et al, 2004;Baxter et al, 2005;Fichet et al, 2007), a fact that facilitates direct comparison as well as integration of independently achieved findings. The high degree of interlaboratory comparability of the used in vivo carrier assay is highlighted by strikingly consistent end-point titration results obtained by us and others (Fichet et al, 2004(Fichet et al, , 2007.…”

An in vitro pyrogen safety test for immune-stimulating components on surfaces

“…However, manual contamination represents not LPS as a purified molecule; imaginable is a mixture of proteins, bacterial and fungal residuals, fatty acids, only to mention some possibilities. The difficulty to detect and to remove protein residuals from surfaces is highlighted by several studies [18,38,42,43], which demonstrates, that a new test system is urgently needed.…”

Inactivation of Microorganisms and Endotoxins by Low Temperature Nitrogen Gas Plasma Exposure

“…Given the drawbacks and limitations of other low temperature sterilization procedures, low temperature gas plasma sterilization could represent a useful alternative (Baxter et al, 2005;Whittaker et al, 2004;Tessarolo et al, 2006;Spilimbergo 2003).…”