JPH11299867A - Sterilizing method for medical tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute prion sterilization without corrosion of metal and organic matter and bad influences on other materials and without requiring a high temperature and high pressure by bringing medical tools into contact with ethylene oxide water solution of a specified density. SOLUTION: Water solution is prepared by dissolving ethylene oxide to be 2.5 to 10 v/v % density by using water or mixture obtained by mixing lower alcohol such as ethanol in less than about 10 wt.% with this for as a solvent. An object to be sterilized is in contact with this for 1 to 72 hours, desirably about 3 to about 60 hours. A temperature at the time is -5 to 50 deg.C, desirably about 0 to 30 deg.C. Its contacting method is optional such as dipping in the water solution. What is required after sterilization is only washing with water and drying. Thus, it is possible to completely eliminate antigenicity from even a medical instrument contaminated by scrapie-infected mouse brain emulsion, e.g. by the processing of about 40 hours.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a medical device, such as a surgical instrument or an endoscope, which is contaminated or possibly contaminated by prions without corroding or deteriorating its material. It relates to a simple disinfection method.

[0002]

2. Description of the Related Art Although prions are still unclear, they are said to be infectious proteins without DNA or RNA because the presence of nucleic acids cannot be explained. To date, human plagues that use this prion as a pathogen include Kuru, Creutzfeldt-Jakob disease and Gerstmann's disease.
Streisler's syndrome and the like are known, and besides humans, scrapie in sheep and goats, spongiform encephalopathy in cattle (so-called mad cow disease) and the like are known. It has been demonstrated that iatrogenic Creutzfeldt-Jakob disease was transmitted to humans via dura transplantation, corneal transplantation, administration of growth hormone extracted from the human pituitary gland, and contaminated EEG electrodes. This transmissible pathogen has been shown to be abundant in the brain and spinal cord of humans in Kuru, and in patients with Creutzfeldt-Jakob disease and Gerstmann-Streisler syndrome, similar transmissible pathogens are found in the brain, spleen, and liver. ,
Lymph node, lung, spinal cord, kidney, cornea, lens, cerebrospinal fluid,
Detected in blood. However, since prions do not generate an immune response such as antibody formation, there is no vaccine, and diagnosis of disease is extremely difficult.

[0003]

Various attempts have been made to inactivate prions. However, the pathogens are exposed to radiation, boiling, dry heat, chemicals (formalin,
It is extremely resistant to conventional inactivation methods against pathogenic microorganisms, including beta propiolactone, alcohol, iodine, acetone, potassium permanganate, sodium dodecyl sulfate, hydrogen peroxide, ethylene oxide gas, etc.). It is known that treatment with high concentration mineral acid or alkali solution at high temperature, or treatment with hypochlorite-alkali solution is inactivated, but high concentration mineral acid or alkali solution causes corrosion to metals and organic substances. Due to its strong oxidizing power, hypochlorous acid-alkali solution also has strong properties, and many medical devices made of materials such as metals, rubbers, and plastics are corroded or deteriorated, and may not be reused. 132 ° C,
Although there is a method of autoclaving for 1 hour under high pressure, large-scale equipment is required, and depending on the material, 1 hour is required.
Some do not withstand high temperatures of 32 ° C. Therefore, there is a long-felt need for a prion disinfection method that has little corrosiveness or other adverse effects on metals and organic substances and does not require high temperature or high pressure.

[0004]

Means for Solving the Problems The present inventors have studied many methods including the disinfection method conventionally used to solve the above-mentioned problems, and found that ethylene oxide was ineffective in gaseous state. However, it was found that a specific concentration of an aqueous solution can effectively attenuate the infectivity of prions without damaging or damaging most medical devices, including medical equipment, based on that knowledge. Through repeated research, the present invention was completed. That is, the present invention provides (1) disinfection of a medical device characterized by contacting a medical device contaminated with or possibly containing prions with an aqueous solution of ethylene oxide having a concentration of 2.5 to 10 v / v%. Law,
(2) The disinfection method according to the above (1), wherein the ethylene oxide concentration is 3 to 8 v / v%, and (3) the contact between the medical device and the aqueous ethylene oxide solution is performed at -5 to 50 ° C for 1 to 72 hours. ) Described disinfection method.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A medical device to be subjected to the disinfection method of the present invention is a concept including all machines, instruments and auxiliary tools used in medical sites such as hospitals.
Various catheters such as venous catheters and heart catheters, surgical instruments such as scalpels, forceps, scissors, etc., various surgical instruments such as endotracheal tubes, suction tubes, tracheal cannulas, bellows rubber tubes, tracheostomy trays, gastroscopes, Examples of medical instruments that are desired to be reused include various endoscopes such as a rectoscope, optical instruments, other artificial dialysis tools, brain drills, saws, and cameras. The solvent used for the aqueous solution of ethylene oxide used in the present invention is usually water, but a suitable amount of a lower alcohol such as ethanol or another hydrophilic organic solvent, a surfactant or the like is added to water, for example, 10% by weight or less. May be mixed. The ethylene oxide concentration of the aqueous ethylene oxide solution brought into contact with the object to be disinfected is usually 2.5 to 10 v / v%, preferably 3 to 8 v / v%. The time for bringing the object to be disinfected into contact with the aqueous ethylene oxide solution is usually 1 to 72 hours, preferably 3 to 60 hours, and the concentration is usually -5 to 50 ° C, preferably 0 to 30 ° C. The method of contacting the object to be disinfected with the aqueous solution of ethylene oxide may be any method, for example, a method of immersing the object to be disinfected in a container containing the aqueous solution of ethylene oxide. After disinfection, the medical device need only be rinsed and dried. The effect of the present invention is that the object to be disinfected is brought into contact with a scrapie-infected mouse brain emulsion, the object to which the brain emulsion is adhered is immersed in a certain amount of the ethylene oxide aqueous solution used for the present invention for a certain time, and the object to be disinfected is removed. It can be confirmed by dialyzing the ethylene oxide aqueous solution after lifting to remove ethylene oxide and examining the presence or absence of antigenicity by Western blotting.

[0006]

The present invention will be described in more detail with reference to the following examples. Example 1 (1) Preparation of sample solution Five silicon tubes to be used as catheters were prepared, and the ends of each tube were immersed in a brain emulsion of a 10 w / v% scrapie-infected mouse, and about 100 μl of the brain emulsion was added.
Attached. Four of these brain emulsion-attached tubes were immersed in test tubes containing 1 ml of a 5 v / v% ethylene oxide aqueous solution, two of which were left at 25 ° C. for 20 hours and the other two were left at 25 ° C. for 40 hours. did. The other one of the brain emulsion attachment tubes was immersed in a test tube containing 1 ml of distilled water at 25 ° C. for 40 hours to serve as a control. The tubes were pulled up from each test tube, and the remaining ethylene oxide aqueous solution was subjected to dialysis using a phosphate buffer to remove ethylene oxide, thereby obtaining a sample solution. For the control in which the tube was immersed in distilled water, the tube was pulled up and used as it was as a control solution.

(2) Measurement of antigenicity by Western blotting The above-mentioned sample solution and control solution were subjected to electrophoresis using a 12.0 w / v% separation gel, and then polyvinylidene difluoride was separated from the separation gel. Transferred onto a Ride (PVDF) film. The transcribed sample is reacted with an anti-peptide antibody designed from the amino acid sequence of the prion protein, and the bound antibody is
Further, the antibody was specifically bound to the antibody and reacted with an enzyme-labeled antibody, and fluorescence was developed using the enzyme labeled with the antibody. Depending on the presence or absence of this color development,
The presence or absence and strength of antigenicity of the sample transferred onto the DF membrane were examined. (3) Results The presence or absence of the antigenicity of each sample solution obtained by the above-mentioned Western blotting method and the intensity of the fluorescence were determined as the presence or absence of the fluorescent color, and the intensity was exposed on a polaroid film (FIG. 1). There are five lanes in total. From the left, a control sample (first lane) was then immersed in a 5 v / v% ethylene oxide aqueous solution at 25 ° C. for 20 hours (second and third lanes) and immersed at 25 ° C. for 40 hours. (Fourth and fifth lanes). Compared to the control, the sample treated for 20 hours had a much thinner band, indicating reduced antigenicity. In addition, no band was observed in the sample treated for 40 hours, indicating that the antigenicity was lost.

[0008]

According to the present invention, medical devices contaminated or possibly contaminated by prions can be corroded,
It can be easily disinfected without deterioration.

[Brief description of the drawings]

FIG. 1 is a photosensitive image on a polaroid film showing antigenicity by Western blotting.

[Explanation of symbols]

 a. 1st lane b. Second lane c. Third lane d. 4th lane e. 5th lane

Claims (3)

[Claims] 1. A method for disinfecting medical devices, comprising contacting a medical device contaminated with or possibly containing prions with an aqueous solution of ethylene oxide having a concentration of 2.5 to 10 v / v%. 2. The disinfection method according to claim 1, wherein the ethylene oxide concentration is 3 to 8 v / v%. 3. The disinfection method according to claim 1, wherein the contact between the medical device and the aqueous solution of ethylene oxide is carried out at -5 to 50 ° C. for 1 to 72 hours.