Novel methods for disinfection of prion-contaminated medical devices.
BACKGROUND
The unique resistance of prions to classic methods of decontamination, and evidence that prion diseases can be transmitted iatrogenically by medical devices pose a serious infection control challenge to health-care facilities. In view of the widespread tissue distribution of the variant Creutzfeldt-Jakob disease agent in human beings, new practicable decontamination procedures are urgently needed.


METHODS
We adapted an in-vivo method using stainless steel wires contaminated with prions to the hamster-adapted scrapie strain 263K. A new in-vitro protocol of surface contamination compatible with subsequent biochemical detection of PrP(res) (protease-resistant form of the prion protein) from the treated surface was developed to explore the mechanisms of action of methods of decontamination under test. These models were used to investigate the effectiveness of innovative physical and chemical methods of prion inactivation.


RESULTS
Standard chemical decontamination methods (NaOH 1N, NaOCl 20000 ppm) and autoclaving in water at 134 degrees C reduced infectivity by >5.6 log10 lethal doses; autoclaving without immersion was somewhat less effective (4-4.5 log reduction). Three milder treatments, including a phenolic disinfectant, an alkaline cleaner, and the combination of an enzymatic cleaner and vaporised hydrogen peroxide (VHP) were also effective. VHP alone, which can be compatible with electronic components, achieved an approximately 4.5 log reduction in infectivity (equivalent to autoclaving without water immersion).


CONCLUSIONS
New decontamination procedures are proposed to ensure the safety of medical and surgical instruments as well as surfaces that cannot withstand the currently recommended prion inactivation procedures.
Fichet
Guillaume
G
CEA/DSV/DRM/GIDTIP, Route du Panorama, 92265 Fontenay-aux-Roses, France.
Comoy
Emmanuel
E
Duval
Christelle
C
Antloga
Kathleen
K
Dehen
Capucine
C
Charbonnier
Aurore
A
McDonnell
Gerald
G
Brown
Paul
P
Lasmézas
Corinne Ida
CI
Deslys
Jean-Philippe
JP
D000818:Animals; D001803:Blood Transfusion; D001921:Brain / Q000382:microbiology*; D006224:Cricetinae; D004203:Disinfection / Q000379:methods*; D004866:Equipment Contamination; D005260:Female; D020007:Implants, Experimental / Q000382:microbiology*; D008647:Mesocricetus; D017096:Prion Diseases / Q000382:microbiology / Q000517:prevention & control*; D012608:Scrapie / Q000517:prevention & control / Q000635:transmission; D013525:Surgical Instruments