(A) physical disinfection method
1. Mechanical disinfection
general application of soap scrubbing, running water, can eliminate most or even all of the bacteria on the hands, the use of multi-layer masks can prevent pathogens from the respiratory tract discharge or invasion. Application of ventilation device filter can make the operating room, laboratory and isolation of the air in the sick room, to protect the sterile state.
2. Thermal disinfection
Including fire, boiling, flowing steam, high heat steam, dry heat sterilization. Can make the pathogen protein coagulation denaturation, lose normal metabolic function.
(1) burning
Where the economic value of small pollutants, metal instruments and corpses can be used in this way. Simple and economical, stable effect.
(2) boiling
boil-resistant items and general metal instruments are used in this method, 100 ℃ 1 ~ 2 minutes to complete the disinfection, but the germ cells have to be a long time. Bacillus anthracis bud cells must be boiled for 30 minutes, tetanus bud cells need 3 hours, botulism bud cells need 6 hours. Disinfection of metal instruments, add 1 to 2% sodium carbonate or 0.5% soft soap and other alkaline agents, which can dissolve fat and enhance the bactericidal power. Cotton fabrics with 1% soapy water 15l/kg, have the effect of disinfection and decontamination. When items are boiled to disinfect, not more than 3/4 of the volume, should be immersed under the surface of the water. Pay attention to leave a gap to facilitate convection.
(3) flow steam disinfection
Relative humidity 80 ~ 100%, temperature of nearly 100 ℃, the use of water vapor condensation in things such as the surface, the release of heat energy, kill pathogens. And when the steam cohesion contraction produces negative pressure, promote the outer layer of hot steam into the supplement, penetrate into the depths of the items, accelerate the heat, promote disinfection.
(4) high-pressure steam sterilization
Usually, the pressure is 98.066kPa, the temperature 121 ~ 126 ℃, 15 ~ 20 minutes that can completely kill the bacterial germs, applicable to heat-resistant, damp items.
(5) dry heat sterilization
Dry heat air conduction is poor, heat capacity is small, penetration is weak, the object is heated slowly. Need 160 ~ 170 ℃, 1 ~ 2 hours to sterilize. Applicable to glass containers that can not take water, metal instruments and so on. Heat tolerance of different pathogens, expressed in terms of heat death time.
3. Radiation sterilization
There are two kinds of non-ionizing radiation and ionizing radiation. The former has ultraviolet, infrared and microwave, the latter includes high-energy electron beams of C rays (cathode rays). Infrared and microwave mainly rely on heat sterilization.
Ionizing radiation equipment is expensive, the goods and the human body has a certain degree of harm, so use less. Currently the most used for the ultraviolet light, can cause cellular components, especially nucleic acids, plasma proteins and acids change, leading to microbial death. Ultraviolet wavelength range of 2100 ~ 3280A, kill microorganisms at a wavelength of 2000 ~ 3000A, 2500 ~ 2650A the strongest effect. UV tolerance to fungal spores is the strongest, followed by bacterial germ cells, bacterial propagules are the weakest, with only a few exceptions. UV penetration is poor, below 3000A can not pass through 2mm thick ordinary glass. Dust in the air and relative humidity can reduce its sterilization effect. The penetration of water decreases with depth and turbidity. However, because it is easy to use and does not harm medicines, it is widely used to sterilize the air and the surface of general articles. Irradiation of the human body can occur skin erythema, ultraviolet ophthalmia and ozone poisoning. Therefore, the use of people should be avoided or with the appropriate protective measures.
Sunlight exposure also relies on the ultraviolet radiation, but due to scattering and absorption in the atmosphere, only 39% of the use of the ground can be reached, so only for microorganisms with low endurance, and must be exposed for a longer period of time. In addition, filtration sterilization in addition to laboratory applications, only ventilation in the building, air filtration can be used, so it is difficult to apply the general disinfection.
(B) chemical disinfection method
Based on the role of the pathogen protein, divided into the following categories.
1. Coagulation protein disinfectants including phenols, acids and alcohols.
(1) Phenols
Mainly phenol, Lysol, hexachlorophenol and so on. Has a special odor, limited bactericidal power. Can make textiles discoloration, rubber items become brittle, there is a certain degree of skin irritation, so in addition to Lysol less applications. Phenol (carbolic acid) (carbolic acid): colorless crystals, with a special odor, pink in moisture, but the disinfectant power is not reduced. For cellular plasma poison, on the bacterial reproduction type 1:80 ~ 1:110 solution, 20 ℃ for 30 minutes can kill, but can not kill the bud cells and resistance of the virus. Add soap can be saponified fat, dissolve proteins, promote its penetration, strengthen the disinfection effect, but more toxic, irritating to the skin, with a bad smell, can not be used for skin disinfection. Lysol (coal phenol soap) (lysol): 47.5% cresol and potassium soap formulated. Reddish-brown, soluble in water, with decontamination effect, sterilization force is 2 to 5 times stronger than the coal phenol. Commonly used as a 2 to 5% aqueous solution, can be used for spraying, rubbing, soaking containers and hand washing. Bacterial reproduction can be killed in 10-15 minutes, the effect on germ cells is poor. Hexachlorophenol (hexochlorophane): bisphenol compounds, slightly soluble in water, soluble in alcohols, esters, ethers, plus alkali or soap can promote dissolution, less toxic and irritating, but stronger bactericidal force. Mainly used for skin disinfection. To 2.5 ~ 3% hexachlorophenol soap hand washing can reduce the skin bacteria 80 ~ 90%, there are reports of neurological damage, so there is appropriate for long-term use.
(2) acids
The bacterial propagules and germ cells have a killing effect. But easy to damage items, so generally not used for room disinfection. 5% hydrochloric acid can be disinfected washing utensils, fruits, plus 15% salt in 2.5% solution can be disinfected fur and leather, 10l/kg heating 30 ℃ soak 40 hours. Lactic acid is often used in air disinfection, 100m3 space with 10g of lactic acid fumigation for 30 minutes, can kill staphylococcus and influenza virus.
(3) alcohol ethanol (alcohol)
75% concentration can quickly kill bacterial reproduction type, the role of general viruses slower, the role of hepatitis virus is not sure, the fungal spores have a certain killing effect, no effect on the germ cells. Used for skin disinfection and thermometer immersion disinfection. Because it can not kill germ cells, it can not be used to disinfect surgical instruments. Isopropylalcohol (isopropylalcohol) on the bacterial killing capacity is greater than 2. Soluble protein disinfectant
Mainly alkaline drugs, commonly used sodium hydroxide, lime and so on.
(1) sodium chlorine oxide
White crystal, soluble in water, strong bactericidal force, 2 to 4% solution can kill viruses and bacterial reproduction, 10% solution can kill tuberculosis bacilli, 30% solution can kill the germ cells in 10 minutes, due to strong corrosive, it is rarely used, and is only used to eliminate the anthrax germ cells.
(2) lime
Water can produce high temperature and dissolve proteins, kill pathogens. Commonly used 10～20% of the milk of lime disinfection excreta, the amount must be 2 times as much as the excreta, stirring the role of 4～5 hours. 20% of the milk of lime used to disinfect anthrax contaminated places, every 4～6 hours to spray once, 2～3 times in a row. Brush the wall 2 times can kill the tuberculosis bacillus. Because of the nature of the unstable, so the application should be freshly prepared.
3. Oxidizing protein disinfectants
Including chlorine disinfectants and peroxide disinfectants. Because of the strong disinfecting power, it is currently the most widely used in the medical epidemic prevention work.
(1) bleach
The most widely used. The main ingredient is calcium hypochlorite [Ca(OCl)2], containing 25-30% effective, unstable, can be light, heat, moisture and CO2 decomposition. It can be decomposed by light, heat, humidity and CO2. Therefore, it should be kept in a dark and dry place in a closed container for not more than 1 year. Hypochlorous acid, the active ingredient, can penetrate into the cell, oxidize the sulfur-hydrogen factor of cellular enzymes, and destroy the cytoplasmic metabolism. It has strong and rapid bactericidal power in acidic environment, and high concentration can kill germ cells, and it is used for disinfection of feces, sputum, pus and so on in powder. Add 200 grams of dry powder per liter, mix well, place 1 to 2 leaflets, urine 5 grams of dry powder per liter, placed for 10 minutes can be. 10-20% emulsion in addition to disinfection of feces and secretions, can be used to spray toilets, contaminated vehicles and so on. If stored for a long time, the actual effective chlorine content should be measured to correct the dosage of preparation. Bleaching powder and tablets containing effective chlorine up to 60 ~ 70%, the use of the proportion can be reduced.
(2) Chloramine-T
Organic chlorine disinfectant, containing 24 to 26% of the effective chlorine, sex is more stable, closed to keep 1 year, only the loss of effective chlorine 0.1%. Slightly soluble in water (12%), irritation and corrosiveness is small, the role of hypochlorous acid is slow. 0.2% 1 hour to kill the bacterial reproduction, 5% 2 hours to kill tuberculosis bacilli, kill the germ cells need more than 10 hours. Various ammonium salts can promote its bactericidal effect. 1~2.5% solution also has a role in hepatitis virus. Active liquid must be used 1 to 2 hours before the preparation, time is too long, the bactericidal effect is reduced.
(3) sodium dichloroisocyanurate
Also known as euclosan, a widely used organochlorine disinfectant, containing 60-64.5% chlorine. It has the advantages of high efficiency, broad-spectrum, stability, high solubility and low toxicity. Water solution can be used for spraying, soaking, rubbing foam, can also be used as dry powder to directly disinfect pollutants, feces and other excreta, the use of the same bleach. Spray directly on the ground, the dose of 10-20g/m2, and paraformaldehyde dry powder mixed with ignition, the gas can be fumigated disinfection, can be mixed with No. 92 coagulant (hydroxyaluminum chloride as the basis for iron powder, sulfuric acid, hydrogen peroxide and other synthetic) to 1:4 to become a "water clear", for drinking water disinfection. It can be used for drinking water disinfection, and can be prepared with sodium sulfate into various disinfectant washing liquid, such as polyester Jingmei, Euchlorine, etc. It has killing effect on hepatitis virus. It has killing effect on hepatitis virus. In addition, there are trisodium phosphate chloride, chlorobromodicyanuric acid and other effects of the same.
(4) peroxyacetic acid
Also known as peroxyacetic acid, colorless transparent liquid, volatile and irritating acidic odor, is a kind of same-effect quick-acting disinfectant, easily soluble in water and ethanol and other organic solvents, with bleaching and corrosive effect, volatile and irritating acidic odor, is a kind of high-efficiency and quick-acting disinfectant, easily soluble in water and ethanol and other organic solvents, with bleaching and corrosive effect, sex is not stable. Easily decomposed by heat, organic matter, heavy metal ions, powerful alkali, etc. 0.01 ~ 0.5%, 0.5 ~ 10 minutes to kill bacterial propagules, 1% 5 minutes to kill germ cells, commonly used concentration of 0.5 ~ 2%, can be disinfected by soaking, spraying, rubbing and other methods, aerosol in airtight conditions (5% concentration, 2.5 ml / m2) and fumigation (0.75 ~ 1.0g/ m3) disinfection.
(5) chlorine peroxide
3 to 6% solution, 10 minutes can be disinfected. 10 to 25% for 60 minutes, can be sterilized, used for heat-resistant plastic products, tableware, clothing and other disinfection. 10% hydrogen peroxide gas deep gel spray disinfection of indoor contaminated surfaces; 180 to 200 ml/m3, 30 minutes can kill bacterial propagation body; 400 ml/m3, 60 Minutes can kill germ cells
Ethanol, absorbed through the lungs can lead to anesthesia, but no damage to the skin, can be applied instead of ethanol.
(6) potassium permanganate
1-5% concentration of immersion for 15 minutes, can kill bacterial propagules, commonly used in eating utensils, fruits and melons disinfection.
4. Cationic surfactants
Mainly quaternary ammonium salts, high concentrations of protein coagulation, low concentrations of inhibition of bacterial metabolism. There are bactericidal concentration, toxicity and irritation of small, no bleaching and corrosive effect, odorless, stable, water-soluble and so on. However, the bactericidal force is not strong, especially on the germ cell effect is not good, affected by organic matter, more contraindications for its shortcomings. Domestic production of new Jieermei, disinfection of Ning (Du Mi Cang) and disinfection of net to disinfection of Ning stronger bactericidal force, the common concentration of 0.5 ~ 1.0 ‰, can be used for skin, metal instruments, tableware and other disinfection. It is not suitable for excreta and secretion disinfection.
5. Alkylated disinfectants
(1) formalin
34 ~ 40% formaldehyde solution, has a strong bactericidal effect. 1 ~ 3% solution can kill the bacterial propagation type, 5% solution for 90 minutes or to kill the germ cells, indoor fumigation disinfection is generally used 20ml / m3 plus an equal amount of water for 10 hours to eliminate the contamination of the germ cells, you need 80ml / m324 hours. m324 hours, applicable to fur, artificial fibers, silk fabrics and other heat-resistant items. Because of its poor penetration, irritation, so the disinfection items should be spread out, the house must be closed.
(2) glutaraldehyde
Role like formaldehyde. In the acidic solution is more stable, but the sterilization effect is poor, in the alkaline solution can be maintained for 2 weeks, but strong to improve the sterilization effect, so usually 2% glutaraldehyde with 0.3% sodium bicarbonate, corrected pH for the compounds (bactericidal effect is enhanced, the stability can be maintained for 18 months. Non-corrosive, broad-spectrum, fast-acting, high-heat, low-toxicity and other advantages, can be widely used to kill bacteria, germ cells and viruses disinfection. It should not be used as skin and mucous membrane disinfection.
(3) ethylene oxide
Colorless liquid at low temperatures, boiling point 10.8 ℃, so at room temperature for the gas sterilizer. Its role is to destroy the microbial protein chemotaxis through alkylation. General application is at 15 ℃ 0.4 ~ 0.7kg / m2, lasting 12 ~ 48 hours. Temperature increase of 10 ℃, sterilization power can be enhanced more than 1 times, relative humidity 30% sterilization effect is the best. It has the advantages of high activity, strong penetration, no damage to articles, no residual poison, etc. It can be used to sterilize paper, books, cloth, fur, plastics, man-made fibers and metal products. Because of the strong penetrating power, it needs to be sterilized in closed containers. Avoid open flame to prevent explosion. Ventilate after disinfection to prevent inhalation.
6. Other
(1) Iodine
Through halogenation, it interferes with protein metabolism. The effect is rapid and long-lasting, non-toxic, and little affected by organic matter. Often sulfur wine, sulfur volts (sulfur and surfactant for indefinite conjugate). Commonly used in skin and mucous membrane disinfection, medical equipment emergency treatment.
(2) Chlorhexidine
For bisulfite compounds. It has a strong disinfecting effect on bacteria. Can be used for hand, skin, medical equipment, clothing and other disinfection, commonly used concentration of 0.2 ~ 1 ‰.