JPH07462A - Prevention of nosocomial infection - Google Patents

Abstract

PURPOSE:To provide a nosocomial infection preventing method high in safety, excellent in sterilizing effect, good in durability, requiring no frequent maintenance, capable of being used widely and effective for antibiotic resistant strains. CONSTITUTION:A metal composite continuously constituted using a metal mixture of metal oxide such as titanium oxide and a second metal such as palladium enhancing photocatalytic function so as to provide the metal mixture on the surface thereof or in the vicinity thereof is adapted in a hospital as a member with which many and unspecified persons come into contact and exposed to light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing bacterial infection in a hospital, and more particularly to a method for preventing nosocomial infection using a material having a photocatalytic function in a place used by an unspecified number of people in a hospital. .

[0002]

2. Description of the Related Art In recent years, MRS resulting from abuse of antibiotics
It has been confirmed that antibiotic-resistant bacteria such as A (methicillin-resistant Staphylococcus aureus) are infected in a hospital, which has become a major social problem. That is, nosocomial infection of antibiotic-resistant bacteria, which started from a higher-order medical institution accommodating a serious medical patient, spreads widely and poses a serious threat to patients and hospital staff. As measures against this, suppression of increase of resistant bacteria by proper use of antibiotics and prevention of spread of resistant bacteria by frequent disinfection / sterilization can be mentioned.

As a method of preventing the spread of resistant bacteria, isolation of resistant bacteria infected persons, disinfection / sterilization of the skin and clothes of infected persons and those who come into contact with infected persons due to medical treatment, disinfection of used medical equipment, etc. There is no choice but to sterilize, and each hospital makes a manual to prevent nosocomial infections. However, even if a person infected with a resistant bacterium is confirmed, it may be difficult to isolate it in a private room, and a secondary infection due to contact may occur before the infection is confirmed. There was a long-awaited preventive measure.

Even in hospitals, infection control measures have been taken in areas such as isolated wards and operating rooms that require a high degree of safety, but in particular, waiting rooms, corridors, washrooms, etc. where an unspecified number of people come and go There are few measures taken in the common area, and even if they are done, frequent disinfection and
In addition to a great burden due to sterilization work, new problems such as safety problems of bactericides and disinfectants, treatment problems of used chemicals, etc. have occurred, and effective and highly safe measures have been demanded.

[0005] Conventionally, as a deodorant and antifungal material which does not depend on a chemical, one utilizing a photocatalytic function of a semiconductor is known. That is, it is known that a semiconductor such as titanium oxide exhibits a photocatalytic function by light having a specific wavelength and has a deodorizing and antifungal function by a strong oxidizing action. Antibacterial and antifungal magazine, Vol. 13, No. 5, p. 211 (1985), describes that a titanium oxide fine particle fixing membrane is useful as a sterilization reactor, and Japanese Examined Patent Publication No. 2-9850 discloses titanium oxide. A method for purifying waste using a semiconductor or the like in which a metal or a metal oxide is supported is described. In the above method, a substance having a photocatalytic function is made into fine particles and then dispersed in a waste liquid which is a target substance to perform a purification treatment.
However, the utilization of the photocatalytic function is at an experimental stage or is transient, and has not yet been practically used effectively.

[0006]

DISCLOSURE OF THE INVENTION The object of the present invention is to provide a wide range of antibiotics which have high safety, excellent bactericidal effect, good durability, and no need for frequent maintenance. It is to provide an effective method for preventing nosocomial infection of resistant bacteria and the like.

[0007]

[Means for Solving the Problems] Claim 1 according to the present application
The invention described is a method for preventing nosocomial infections, wherein as a member in a hospital, a metal oxide whose surface and its vicinity substantially have a photocatalytic function, and a second metal which improves the photocatalytic function of the metal oxide. Consisting of a metal mixture containing
The inside is made of a metal mixture containing substantially the same kind of metal that constitutes the metal oxide and a second metal that improves the photocatalytic function of the metal oxide, and the surface and its vicinity and the inside. Is applied to a material (hereinafter, referred to as a metal mixture composite), and the member is exposed to light.

The invention according to claim 2 related to the present application is the method for preventing nosocomial infection according to claim 1, wherein the member is:
A metal mixture containing the same kind of metal as the metal oxide having a photocatalytic function and a second metal for improving the photocatalytic function of the metal oxide is produced, and the metal mixture is formed into a desired shape. It is characterized in that it is a composite obtained by processing and oxidizing the surface layer portion of the processed metal mixture.

[0009]

The method for preventing nosocomial infection according to the present invention applies a substance that exhibits a photocatalytic function, which is a complex of a metal mixture exposed to light, to a member in a hospital. It exhibits an excellent bactericidal effect against adhered bacteria and has good durability such as abrasion resistance. Also, a substance that exhibits a photocatalytic function, as long as it is exposed to light,
Without special maintenance, the germicidal effect is exhibited semi-permanently, there is no undesirable environmental pollution and no waste is generated, so safe and effective nosocomial infection can be prevented.

[0010]

The present invention will be described in more detail below.

In the method for preventing nosocomial infection according to the present invention, as a member in a hospital to which a substance having a photocatalytic function is applied,
Floors, walls, window frames, handrails, handles, etc., especially in places where a large number of unspecified things come into contact, such as hospital rooms, corridors, waiting rooms, washrooms, etc.
Examples include faucets, bed frames, curtains and carpets. In other words, even in hospitals, although infection control measures are completely implemented in areas that require a high degree of safety, such as isolation wards, intensive care units, operating rooms, etc., general hospital rooms where an unspecified number of people come and go, This is because the infection control measures in the corridors, waiting rooms, washrooms, etc. were insufficient.

Among the above members, floor, wall, window frame, handrail,
In the case of a solid member such as a handle, a faucet, a bed frame, etc., the member itself should be composed of the metal mixture composite, or the surface of the member should be covered with a thin film of the metal mixture composite. Is preferred. Examples of the metal material include metal panels used for walls, doors, flooring and the like, handrails such as window frames, stairs, and washrooms, door handles, water faucets and chairs, and metal frames such as sleepers. These may be composed of a metal mixture composite or may be formed by processing the surface of the metal mixture composite into a thin film. Examples of the inorganic material include tiles, boards such as gypsum, wall materials by spraying or painting, glass and wash basins, ceramic materials such as toilet bowls, and the like, and organic materials include resinous floor materials, wall materials, Examples include resin handles such as door handles, taps, chairs, and sleepers. In these solid members, a metal mixture composite processed into a thin film is applied to the surface. The application method is to adhere the thin film to the surface with an adhesive or a thin plate. The metal mixture composite molded in step (1) may be fixed with a fastener such as a bolt or a nail.

Examples of the substance exhibiting a photocatalytic function used in the method for preventing nosocomial infection of the present invention include, for example, a metal oxide semiconductor such as titanium oxide on the surface and in the vicinity thereof and palladium or the like for improving the photocatalytic function. The metal mixture
The inside is a metal mixture of titanium or the like and palladium or the like, and examples thereof include a metal mixture composite in which both are continuously formed. In the present invention, “substantially” is meant to include the presence of impurities and mixtures to the extent that the effects of the present invention are not impaired.

Specific examples of the metal oxide used on the surface and in the vicinity thereof include the substances described in Japanese Patent Publication No. 2-9850, particularly titanium oxide, iron oxide, tungsten oxide, zinc oxide, Strontium titanate and the like are widely known. The semiconductor used in the method for preventing nosocomial infection of the present invention may be any of these, but titanium oxide is particularly preferable because of its bactericidal effect and easy availability. Examples of the second metal that modifies the metal oxide in order to improve the photocatalytic function of titanium oxide or the like include, for example, platinum,
Examples thereof include those selected from the group consisting of gold, palladium, silver, copper, nickel, cobalt, rhodium, niobium, and tin. Among them, platinum, gold, palladium, from the viewpoint of effect,
Silver is more preferable, and palladium is preferable in view of easy processing and price. The amount of modification is preferably 0.01 to 20% by weight based on the metal oxide in the present invention. In addition, examples of the metal used inside include the metals used for the metal oxide, that is, titanium, iron, tungsten, zinc, strontium, and the like. The second metal for improving the photocatalytic function is the same as described above.

As a method for producing the metal mixture composite, for example, a metal mixture of the metal and a second metal for improving the photocatalytic function is produced, processed into an arbitrary shape, and then processed. The surface layer of the metal mixture may be oxidized. Thus, the surface is a metal mixture or alloy of a metal oxide having a photocatalytic function and a second metal for improving the photocatalytic function, and the inside is a metal mixture (alloy) having no photocatalytic function, Since both of them are continuously formed, the phase having a photocatalytic function does not peel off from the metal mixture as a simple substance, and has practical durability, peel resistance, abrasion resistance, etc. ing.

FIG. 1 is a model cross-sectional view showing the phase state of the metal mixture composite in the case where the metal is titanium Ti and the second metal for improving the photocatalytic function is palladium Pd.

The TiO ₂ phase 10 and the TiPd ₂ phase 14 are dispersed on and near the surface, the TiO ₂ phase exhibits a photocatalytic function, and the TiPd ₂ phase promotes the functions. As it goes inside, the Ti phase 12 that is not related to the photocatalytic function
And the Ti phase 12 and the TiPd ₂ phase 14 are dispersed, and these are continuously formed. Thus, since the titanium oxide / metal phase having a photocatalytic function and the titanium / metal phase serving as a carrier continuously form the same structure, the photocatalytic phase does not peel from the carrier,
It has strength and wear resistance that can be practically used.

As a method of applying the metal mixture composite to the member in the hospital, the metal mixture is molded according to the shape of the member having a flat surface, a curved surface or a complicated shape surface, and then an oxidation treatment is performed. And a method of applying a thin film of the metal mixture composite in advance and adhering or locking it to the surface of the member.

In the present invention, the member needs to be exposed to light, but the light energy has a wavelength corresponding to exciting the photocatalyst and contributes to the photocatalytic reaction. Light energy containing many ultraviolet wavelengths of 400 nm or less is preferable. Examples of the light energy source include natural light sources of sunlight, light emitted from mercury lamps, light emitted from fluorescent lamps, light generated from halogen lamp type filament lamps, short arc xenon light, artificial light sources such as laser beams. An artificial light source may be used at the same time as an auxiliary light source for sunlight.

The above-mentioned light irradiation method includes a method of directly irradiating a substance that exhibits a photocatalytic function applied to a member, a method of irradiating a thin film in a multifaceted manner by using sunlight and artificial light in combination, etc. However, it is not necessary to irradiate a special light, and a sufficient effect can be obtained by using the light of a fluorescent lamp in a hospital. However, since the bactericidal effect is not expressed in the shaded areas where the light of the illumination does not reach, it is preferable to use another light irradiation means, if desired, to express the bactericidal effect in the entire area where the person comes into contact. In addition, it is preferable to apply light having a wavelength that promotes the photocatalytic action with sufficient intensity to a member that requires a high sterilization effect.

As a specific method of applying the material having a photocatalytic function according to the present invention to a member in a hospital, a method of directly using a material composed of the above metal mixture composite,
For example, specifically, a method of producing a faucet, a bed frame, a window frame, and the like from the metal mixture, directly obtaining a member by performing an oxidation treatment, and directly installing the member at the application site, a metal mixture composite, In addition to a method of forming a thin film or a thin plate and disposing it on the surface of a member, a method of using a metal tile formed of a metal mixture composite as a floor material, a wall material, a ceiling material, or the like can be used.

(Example 1) Evaluation of bactericidal property A metal mixture consisting of 90 mol% titanium and 10 mol% palladium was prepared and shaped into a tile of 20 cm ² , and then used as a cathode in a 1 wt% phosphoric acid aqueous solution. Anodizing treatment was performed at a voltage of 32 V for 30 minutes using metallic aluminum to oxidize the titanium layer in the alloy and form a titanium oxide layer of several μm on the surface to obtain a metal mixture composite tile.
The test piece was used.

FIG. 2 shows a device for evaluating bactericidal properties. 2 × 1 on the surface of the tile 16 made of the metal mixture composite, which is the test piece.
A cell suspension (bacterial solution) 18 in which 0 ⁴ MRSA was dispersed in physiological saline was applied, and after drying, a distance of 30 cm was applied, and light was irradiated for 15 minutes from the top by a white fluorescent lamp 20 of 15 W. after the Celsus pen John 18 on the tile 16 the entire surface were transferred to the medium scraped with a cotton swab, the culture medium was cultured for 24 hours at 37 ° C., it was counted the number of viable bacteria MRSA, at 0.2 × 10 ⁴ there were. It was revealed that about 90% of MRSA was killed by the light irradiation for 15 minutes. The ultraviolet irradiation dose under this condition was measured and found to be 4.91 μW per cm ² , which was 2
The irradiation amount of the test piece of 0 cm ² was 98.2 μW / 20c.
It was m ² . The number of dead MRSA is 1.8 x 10
^{Was 4} . The number of dead MRSA was divided by the amount of UV irradiation and the irradiation time (minutes), and the obtained value was taken as the bactericidal effect. In this evaluation, the bactericidal effect was 12.2 (cells / min
-Expressed in μW).

The results of the bactericidal effect of the white fluorescent lamp are shown in FIG. The graph represented by the solid line in FIG. 3 is the light irradiation time and M
The relationship of the survival rate of RSA is shown. As is clear from the results, the test piece using the tile made of the metal mixture composite exhibits a high bactericidal effect against MRSA when irradiated with a white fluorescent lamp.

A similar test was conducted on E. coli. The results are also shown in FIG. The graph represented by the broken line in FIG. 3 represents the relationship between the light irradiation time and the survival rate of Escherichia coli. 97% or more of the Escherichia coli was killed by irradiation with a fluorescent lamp for about 15 minutes, and it was revealed that this test piece exhibits a high bactericidal effect not only on MRSA but also on Escherichia coli.

(Example 2) Evaluation of Nosocomial Infection Prevention Method In a hospital, the light irradiation conditions in the operating room, operating table, general ward, outpatient waiting room and corridor, outpatient consultation room, general office work, and service area were measured. The bactericidal effect in the area and the time required to kill 50 cells / cm ² of bacteria when the titanium oxide thin film coated tile was applied were calculated according to the results of Example 1 and shown in Table 1. No special addition was made to the light irradiation, and only the illumination in each normal area was used.

[0027]

[Table 1]

It is generally known that the number of viable bacteria in a hospital is less than 50 cells / cm ² ,
In any area, only about 1 by normal lighting
It was estimated to kill that number of bacteria in ~ 15 minutes.

It is known that the titanium oxide used in this embodiment can obtain various colors depending on the film thickness thereof. Since the film thickness of titanium oxide is almost proportional to the anodizing potential, various colors can be easily obtained by controlling the oxidizing potential in the anodizing treatment, which is also preferable in terms of design.

In this embodiment, a metal mixture containing titanium oxide and palladium is used as the material having a photocatalytic function, but a mixture of other metal oxide and metal may be used. Furthermore, the mixing amount of the second metal for improving the photocatalytic function can be freely selected within a range that does not impair the effects of the present invention.

[0031]

INDUSTRIAL APPLICABILITY The method for preventing nosocomial infection of the present invention is widely used because it is highly safe, has an excellent bactericidal effect against antibiotic-resistant bacteria, has good durability, and does not require frequent maintenance. be able to.

[Brief description of drawings]

FIG. 1 is a model cross-sectional view showing the inside of a metal mixture composite body obtained from a titanium-palladium alloy.

FIG. 2 is a schematic view of a sterilization evaluation apparatus.

FIG. 3 is a graph showing the relationship between the light irradiation time and the survival rate of MRSA and Escherichia coli.

[Explanation of symbols]

10 Titanium oxide (TiO ₂ ) phase 12 Titanium (Ti) phase 14 Titanium-palladium mixed (TiPd ₂ ) phase 16 Titanium oxide-containing metal mixture composite tile 18 Cell suspension 20 Fluorescent lamp (15 W)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hasegawa Kan 2-5-14 Minamisuna, Koto-ku, Tokyo Inside the Takenaka Corporation Technical Research Institute (72) Inventor Yasuhiko Yoshioka 2-5 Minamisuna, Koto-ku, Tokyo No. 14 Incorporated Takenaka Corporation Technical Research Institute (72) Inventor Noburou Tsubouchi 2-5-14 Minamisuna, Koto-ku, Tokyo Incorporated Takenaka Industrial Engineering Laboratory (72) Inventor Seiichi Hosoi Osaka City Central Osaka 4-1-1-13, Honcho, Takenaka, Ltd. Inside the Osaka Main Store (72) Inventor, Toru Katayama 4-1-1-13, Honmachi, Chuo-ku, Osaka-shi, Osaka Prefecture (72) Inside the Osaka Main Store (72) Inventor Fujishima Akira 5 710, Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Kazuhito Hashimoto 2000, Kosugaya-cho, Sakae-ku, Yokohama-shi, Kanagawa 10 Minami-Kosugaya Houses 2 506

Claims (2)

[Claims] 1. A member in a hospital comprising a metal mixture whose surface and its vicinity include a metal oxide substantially having a photocatalytic function and a second metal for improving the photocatalytic function of the metal oxide. , A metal mixture whose inside is substantially the same kind of metal that constitutes the metal oxide and a second metal that improves the photocatalytic function of the metal oxide, and the surface and its vicinity and the inside A method for preventing nosocomial infections, characterized in that a material consisting of and is applied, and the member is exposed to light. 2. A metal mixture, wherein the member contains a metal of the same kind as that constituting the metal oxide having a photocatalytic function and a second metal for improving the photocatalytic function of the metal oxide, The method for preventing nosocomial infection according to claim 1, which is a composite obtained by processing the metal mixture into a desired shape and oxidizing the surface layer portion of the processed metal mixture.