NR ATFU
AU Keevil,C.W.; Pinchin,H.; Lipscomb,I.P.
TI Use of advanced light microscopy to rapidly assess the decontamination of PrPsc-infected tissue on surgical stainless steel
QU International Conference - Prion 2005: Between fundamentals and society's needs - 19.10.-21.10.2005, Congress Center Düsseldorf - Oral sessions ORAL-25
PT Konferenz-Vortrag
AB
Hospital sterile service departments (SSDs) currently rely on insensitive, yet simple visual confirmation of cleanliness as an assessment of the efficacy of cleaning surgical instruments. In recent years evidence has emerged of a highly robust, infection-related, fatal, proteinaceous agent termed prion (PrPsc) found in spongiform encephalopathies, such as variant Creutzfeldt-Jakob disease (vCJD), and their ability to infect iatrogenically through contaminated medical devices even after standard inactivation procedures have been employed. As the sensitivity of the current recommended protein test, ninhydrin, has been brought into question, concern has further increased and the requirement for a new means of assessing surgical instrument contamination has been raised.
A novel microscopy technique; Episcopic Differential Interference Contrast microscopy, has been developed. This allows episcopic illumination to produce differential interference contrast images and as such enables the system to rapidly, and sensitively visualise opaque or semi opaque surfaces. An appraisal was undertaken of various detergent or enzymatic cleaning reagents. Their cleaning activity was compared in the laboratory with murine normal brain homogenate or ME7 scrapie-infected brain homogenate under simulated automated washer/disinfector conditions.
The cleaning chemistries displayed an initial sharp decrease in surface contamination followed by a decline in cleaning efficacy; all of the chemistries were able to remove greater than 90% of soiling after 90 minutes, although their effectiveness did vary. Nevertheless, even after this length of time, a highly cleaning-resistant proteinaceous sub-population appeared to remain attached to the surface. In SSDs the cleaning solutions only have approximately 5 minutes of contact time, which from these results would indicate that significant amounts of soiling may remain on the instruments surface (around 50%), and may lead to an increase iatrogenic risk.
IN Die Autoren empfehlen eine episkopische differenzielle-Interferenz-Kontrastmikroskopie (Episcopic Differential Interference Contrast microscopy), mit welcher sich Proteinreste auf Oberflächen durch Interferenzen sehr schnell und hochsensitiv erkennen lassen sollen. Mit dieser Methode verglichen sie die Effektivität verschiedener Dekontaminationsmethoden auf der Basis von Detergentien und Enzymlösungen. Sie stellten fest, dass trotz einiger Unterschiede alle Methoden in kurzer Zeit den größten Teil der Proteine von den Oberflächen entfernten, ein gegenüber allen Prozeduren hartnäckig resistenter Rest von Proteinen sich aber auf den Oberflächen hielt.
AD C.W.Keevil, H.Pinchin, I.P.Lipscomb, Environmental Healthcare Unit, School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton. SO16 7PX, UK
SP englisch
PO Deutschland