Disinfection is an essential part of the antiseptic process . According to the German Pharmacopoeia (DAB), disinfection means: "To put dead or living material in a state that it can no longer infect ".
Chemical or physical methods can be used for disinfection. There are various lists of tested disinfectants and methods in which they are listed according to different areas of application: Hygienic and surgical hand disinfection , skin antiseptics, surface, instrument, laundry and room disinfection as well as disinfection of waste. Some of these measures are part of basic hygiene .
Technically, a distinction is made between disinfection and sterilization . One speaks of disinfection in the case of a germ reduction in a specified test procedure with certain test bodies by a factor of at least 10 −5 , which means that of the original 1,000,000 germs capable of reproduction (so-called colony - forming units (CFU)) no more than ten survive (exception: Laundry disinfection process: germ reduction by a factor of at least 10 −7 ). Disinfecting processes are also used for preservation .
Unit of measure for germ reduction
A log 10 level is a unit of measurement for germ reduction by a power of ten: a log 10 level reduces the amount of germs present by 90%; of the original population of 100, only ten survived. The hand washing with soap corresponds to two log 10 increments, thus reducing the number of bacteria by 99%. Disinfection is only achieved with about four to seven log 10 levels.
The disinfection plan regulates the details of cleaning, disinfection and sterilization with detailed indications, product and dosage information as well as exposure times. It is part of the hygiene plan that health facilities must maintain to protect against infection. In healthcare facilities with a very limited scope of services, the cleaning and disinfection plan can represent the minimum variant of a hygiene plan.
Disinfectants are chemical substances for surface, instrument or skin disinfection as well as for water disinfection. Depending on the pathogen (e.g. bacteria , viruses , fungi , spores ) one speaks of bactericides , virucides (see also virus inactivation ), fungicides and sporicides (see also biocide and antimicrobial substances ). They are to be distinguished from drugs such as antibiotics , antivirals and antimycotics , even if some of these can also be used superficially.
Oxidizing agents as active ingredients
All substances that split off oxygen as an oxidizing agent are bactericidal and act against both enveloped and non-enveloped viruses. They are only partially and to a limited extent effective against fungi, spores and tuberculosis pathogens (see table below).
|Peracetic acid||sporicidal||Surfaces, instruments|
|Chlorine dioxide||quickly sporicidal||Surfaces, instruments, water|
|Hydrogen peroxide||slowly sporicidal||Surfaces, instruments, water , skin, mucous membrane|
|Sodium hypochlorite||sporicidal||Surfaces, instruments, water, skin
|chlorine||slowly sporicidal||Water, instruments|
|ozone||slowly sporicidal||Water, instruments; Ozone for vehicles|
|Chloramine T||sporicidal||Surfaces, water, instruments, skin, mucous membrane|
|Iodine||slowly sporicidal||Skin, mucous membrane|
Hydrogen peroxide (H 2 O 2 ) is suitable as a three percent aqueous solution for disinfecting skin and mucous membranes because it only kills organisms on the surface, whereas it is decomposed in the tissue by catalase / peroxidase . In higher concentrations (usually 30%) it is used in medicine, pharmacy and food production for the sterilization of instruments and containers . The fumigation of rooms and ventilation systems for decontamination purposes with H 2 O 2 can represent an effective alternative to the use of formaldehyde gas if certain requirements are met.
Other active ingredients
|Aldehydes ( formaldehyde , glutaraldehyde / 1,5-pentanedial)||bactericidal||tuberculocide||sporicidal||fungicide||virucidal (enveloped and uncovered)||Room, equipment and surface disinfection|
|Ethylene oxide||bactericidal||?||sporicidal||fungicide||virucidal||Surfaces, instruments, thermolabile drugs, food|
|Alcohols (e.g. ethanol , 1-propanol )||bactericidal||tuberculocide||ineffective||fungicide||partially virucidal (only covered)||Skin, mucous membrane, surfaces, instruments|
|Phenols ( chloroxylenol , triclosan )||bactericidal / bacteriostatic||?||ineffective||fungicide||virucidal (variable)||Skin, mucous membrane, surfaces, instruments|
|Nitrogen compounds (eg. As quaternary ammonium salt , for example. Benzalkonium chloride )||bactericidal (limited for Gram-negative )||?||ineffective||fungistatic||partially virucidal||Skin, mucous membrane|
|Other detergents (e.g. also surfactants such as cetyltrimethylammonium bromide )||bactericidal (variable)||?||ineffective||fungistatic||ineffective||Skin, mucous membrane|
|Chlorhexidine||bacteriostatic||?||ineffective||fungistatic||virustatic||Skin, mucous membrane|
|Guanidine derivatives (e.g. coconut propylene diamine guanidinium acetate)||bactericidal||?||sporicidal||fungicide||virustatic||Surfaces, spaces|
Octenidine (octenidine dihydrochloride,
often in combination with phenoxyethanol )
|bactericidal||tuberculocide||ineffective||fungicide||virucidal||Skin, mucous membrane|
|Polyhexanides||bactericidal||tuberculocide||ineffective||ineffective||virucidal (enveloped and uncovered)||Skin, mucous membrane|
|Copper , organic mercury compounds , silver||bactericidal||ineffective||ineffective||ineffective||ineffective||Silver: infection prophylaxis in wound dressings, coating of catheters, water disinfection|
Legend: effective / limited, variable, partially or only statically effective / ineffective
An active ingredient that can render spores incapable of germination is a sporicidal active ingredient or a sporicide . The active substances listed in the table, such as peracetic acid , hydrogen peroxide , ozone and sodium hypochlorite, belong to the sporicides . They are strongly reacting or rapidly disintegrating oxidizing agents . They must be stored protected from heat and light and chemically stabilized if they are not to be used for disinfection immediately after production.
Hydrogen peroxide forms a “fast” sporicidal mixture with peracetic acid and acetic acid , which is stabilized by the acetic acid. Such mixtures are only used in the professional sector - clean room technology. When added to alcohols, hydrogen peroxide can improve their effectiveness in hand disinfection .
Sporicidal disinfectants require a minimum exposure time to penetrate the armor covering of the spore. This required exposure time is then the measure of its efficiency as a sporicide.
Sporicide is tested according to EN standard 13704 with spores from Bacillus subtilis . In order for an active ingredient or disinfectant to be classified as sporicidal, a 3-log reduction in spores must be brought about .
To test surface disinfectants, test organisms are used in accordance with the European standard CEN TC 216 WG1 and WG3.
|Offer of a reward||Test organisms||Stage 2 Stage 1||Stage 2 Stage 2|
|Bactericidal||Pseudomonas aeruginosa , Staphylococcus aureus , Enterococcus hirae||EN 13727||EN 13697|
|Fungicide , levurocide||Candida albicans , Aspergillus brasiliensis||EN 13624||EN 13697|
|Mycobactericide||Mycobacterium terrae , Mycobacterium avium||EN 14348||-|
|sporicidal||Bacillus subtilis spores||EN 13704||-|
|Tuberculocide||Mycobacterium terrae||EN 14348||-|
|Virucidal||Poliovirus , Adenoviridae , Murine Norovirus||EN 14476||-|
In phase 2, step 1, a quantitative suspension test is first carried out in a test tube under practical conditions. In phase 2, stage 2, the effectiveness of the disinfectants is carried out in a practical test.
For the correct disposal of disinfectants, their concentration is relevant. In ready-to-use solutions, such as liquids, sprays or wipes, which are used for hand or skin disinfection, the disinfecting agent is heavily diluted. The same applies to solutions that are used for surface or instrument disinfection, for. B. be used in hospitals, medical practices or care facilities. For correct disposal, existing manufacturer information according to the safety data sheet must be taken into account. In the case of the ready-to-use, highly diluted solutions, the waste key number 180107 (chemical waste) is usually used.
The situation is different with concentrates: these must be disposed of as hazardous waste. The collection must take place in tightly closed special containers. The transport is to be organized according to dangerous goods law . The disposal takes place with the marking as hazardous waste with collective or individual disposal certificate.
Problems with the use of chemical disinfectants
Disinfectants must be used professionally and strategically. A habitual use in the household , on the other hand, is rather disadvantageous. Improper use can lead to resistance if, in particular, the active ingredient concentration and exposure time, and thus the germ reduction factor, are too low (selection of robust strains). Bacteria that are resistant to disinfectants often show an increased resistance to antibiotics .
Damage to the skin
The habitual use of disinfectants to clean the hands in the household can destroy the health-threatening germs at the same time the skin flora , which z. B. protects against dermatoses . If you only use soap or the like instead, the surfactants contained have less of a disinfectant ( microbiocidal ) effect than they increase the water solubility of dirt. Soap removes the dirt that was last brought in from the outside rather than the permanent skin flora that is worth preserving.
Appropriate skin and hand disinfection in medicine, however, does not permanently damage the skin flora. Only a relatively small number of skin flora microbes are killed. The locally decimated skin flora soon regenerates. The combination of excessive washing with soap before hand disinfection and the disinfection itself can, however, permanently damage the skin flora, as a large part of the skin flora settles in the fatty sebum of the hair follicles (hair follicles). Before surfactant-free or low-surfactant disinfectants these microbes are protected, disinfection destroys only the hair farther microbes. These are replaced in the following hours or days by the spread of the germs formed in the hair follicles. On the other hand, excessive washing of the hands with soap dissolves the protective sebum. Subsequent hand disinfection then also destroys the germs in the hair follicle, from which the surrounding skin flora would otherwise regenerate.
Impact on the environment
If disinfectants are used in the household without hesitation or if their residues are not properly disposed of, they end up in rivers or sewage treatment plants and disrupt the important interaction of a large number of bacterial species, which reduces the cleaning effect (in the clarifier or in the water). Many disinfectants (e.g. phenol) also have an ecotoxic effect on water.
Other "side effects" of disinfectants
Some active ingredients in disinfectants can irritate the human mucous membranes, especially the nasal mucous membrane. Examples are chlorine as well as benzene and phenol , as well as other aromatics .
For all disinfectants, the hazard pictograms and warnings on the label provide information about the specific hazards of the substance. Many of these agents are corrosive, irritating to the skin and / or mucous membranes, are flammable or even explosive, or can release toxic chlorine gas when mixed with other household cleaners . In addition, some disinfectants are toxic or carcinogenic to humans ( aldehydes , phenol ) and some can cause allergies . Oxidizing agents such as peroxides or halogens can attack certain metals.
Disinfection by irradiation
The use of low-temperature plasma (TTP) is a technology for disinfection with cold plasma , which can also kill antibiotic- resistant pathogens even through clothing at a temperature of below 100 ° C. It is suitable, for example, for disinfecting air, surfaces, objects, hand disinfection and the treatment of poorly healing chronic wounds . In in vitro tests, not only a killing effect against bacteria, but also against viruses and fungi could be observed. Treatment with TTP for mycoses such as athlete's foot appears to be possible, but this has yet to be confirmed by further studies.
Disinfection of liquids
Wastewater , drinking water or liquid media can be disinfected using various methods. A fundamental distinction is made between chemical and physical methods of disinfection.
- Common chemical processes are based on the addition of chlorine , chlorine dioxide , hydrogen peroxide , dimethyl dicarbonate ( cold disinfection ), silver ions ( oligodynamics ) or ozone .
- Common physical processes are based on heating the medium ( pasteurization or steam pressure in an autoclave ) or irradiation with UV light .
- The catalytic disinfection with a full metal catalyst in the presence of small amounts of hydrogen peroxide is new .
Disinfection of drinking water in Germany
In addition to the § 37 of the Infection Protection Act calls for the drinking water regulations (TrinkV 2001) in the freedom of the drinking water of germs. In addition, the recognized rules of technology , which are laid down in DIN regulation 1988 and in DVGW regulations, must be observed, worksheets W 551 "Technical measures to reduce the growth of legionella" and W 553 "Dimensioning of circulation systems in central drinking water heating systems ", as well as VDI regulation 6023 "Hygiene in drinking water installations". Permissible substances and methods of defense are described in an updated list from the Federal Environment Agency in accordance with 2001 Drinking Water Ordinance.
To do this, all draw-off points must be operated with hot water at 70 ° C for three minutes.
Most of the time, chlorine, chlorine dioxide, or sodium and calcium hypochlorite solutions are used for disinfection; ozone is rarely used in drinking water hygiene because of the high expenditure . The dosage of chlorine gas solutions or the addition of sodium and calcium hypochlorite solutions is permitted. In addition, chlorine can be electrolytically produced and metered on site or a chlorine dioxide solution is produced and added on site. Ozone and ozone solutions must also be generated on site and added in suitable quantities. According to § 6 of the Drinking Water Ordinance, only the minimum amount of disinfectants may be added. The cold sterilization is used for disinfection of some drinks.
Bacteria are inactivated by irradiation with UVC at 254 nm, but Legionella can survive in amoeba. Ultrasound can also be used to improve the effect.
With SODIS , UV-A radiation from the sun that has a longer effect is used together with the heat for simple water disinfection at household level in developing countries.
Membranes are also increasingly being used to remove microorganisms. With micro- and ultrafiltration , bacteria and sometimes even viruses can be filtered out with a pore size of less than 0.2 µm. Ultrafiltration systems with a separation limit of 0.02 µm and an integrated, daily check of the membrane for defects are approved in the United States as a disinfection method in drinking water. In the USA, proof of complete removal of bacteria, viruses and parasites is required for such systems; the daily test must be able to guarantee complete removal of bacteria and parasites in the long term.
Legal classification in Germany
The manufacture and use of disinfectants are regulated by laws such as the Medicines Act. The product classification is relatively complex, because it is always based on the specific application, but sometimes also on the ingredients. Ethanol, for example, can fall into any product category, depending on the specific disinfection application:
- Pharmaceutical law
- Disinfectants are medicinal products for human use when they are used on humans to prevent or treat infectious diseases (for example, ethanol for disinfection when blood is drawn).
- Disinfectants are veterinary medicinal products when they are used on animals to prevent or treat infectious diseases or when they are used to make devices antiseptic before these devices come into contact with the animal or to make the veterinary treatment area antiseptic (for example, ethanol to disinfect a Wound).
- Medical device law
- Biocide law
- Disinfectants are biocides if they are to be used for surface and room disinfection in clinical, public (e.g. swimming pools) or private areas in order to prevent infections. Since they have been subject to an approval procedure for a number of years, the use of individual products can be restricted to certain groups of people (e.g. professionally qualified persons, disinfectors ).
Hand and skin disinfectants are also subject to approval in accordance with the EU Biocide Regulation across the EU , but in Germany they are still a dispute between the Federal Institute for Drugs and Medical Devices (BfArM) in Bonn and the Federal Institute for Occupational Safety and Health (BAUA) in Dortmund.
The VDI 6022 contains the accepted engineering standards for ventilation and air conditioning technology.
- Hand disinfection / hand disinfectant
- Preparation dispenser
- Epidemic mat
- List of disinfectants and methods tested and recognized by the Robert Koch Institute. In: Federal Health Gazette. Health research and health protection, 46 (1), 2003, pp. 72-95,
- M. Klade, U. Seebacher, M. Jaros: Potential threats to humans and the environment from disinfectants in hospital hygiene. A comparative assessment. In: Hospital hygiene and infection prevention. Volume 24, No. 1, 2002, pp. 9-15,
- Udo Eickmann, Jochen Türk, Renate Knauff-Eickmann, Kerstin Kefenbaum, Monika Seitz: Disinfectants in the health service. Information for a risk assessment. In: Hazardous substances - keeping the air clean , 67 (1/2), 2007, pp. 17-25,
- GE McDonnell: Antisepsis, Disinfection, and Sterilization: Types, Action, and Resistance . Blackwell Publishing, 2007, ISBN 978-1-55581-392-5 .
- S. Block: Disinfection, Sterilization, and Preservation . Edition: 5. Lippincott Williams & Wilkins, 2001, ISBN 0-683-30740-1 , p. 220.
- R. Walter, K. Büsching, H. Lausch: Water disinfection with full metal catalysts and hydrogen peroxide. In: water, soil, air. 1–2 / 2005, p. 30.
- J. Koppe, S. Winkens: Complete compliance with VDI 6022 - made possible by solid-state catalysts in the H2O2 disinfection of air humidifiers
- G. Franke, J. Koppe, M. Raulf-Heimsoth, R. Walter, M. Weinkamp, R. Weyandt: MOL ® CLEAN process - a hygienic alternative to conventional biocides . Lecture given on November 9, 2001 in Munich at the 3rd symposium "Indoor Climate in the Wende"
- Announcement regarding the instruction for the execution of the §§. 19 to 29 of the law of June 23, 1880 / May 1, 1894 on the defense and suppression of animal diseases . Appendix A. Instructions for the disinfection procedure for infectious diseases of domestic animals . (Germany, 1895)
- Detailed article in the maintenance wiki
- List of disinfectants and methods tested and recognized by the Robert Koch Institute (PDF; 1 MB)
- Vienna disinfectant database WIDES
- German Society for Hygiene and Microbiology
- Candles with essential oils can destroy microbes . In: Image of Science. June 21, 2004
- Institute for Hygiene and Public Health at the University of Bonn: Hygiene tips for kids. Hand hygiene information. March 2015 ; accessed on February 21, 2019.
- General explanations on the hygiene plan of various health facilities. Health Service of the City of Vienna, Department of Supervision and Quality Assurance. Status: November 2011 ; accessed on March 17, 2019.
- Detlef Reichenbacher, Marc Thanheiser, Dominique Krüger: Current status on room decontamination with gaseous hydrogen peroxide . (PDF). In: Hyg Med , 2010, 35 , pp. 204-208; Retrieved June 9, 2015.
- Hygiene and disinfection in hospitals and households - an introduction . ( Memento of December 2, 2012 in the Internet Archive ) (PDF, 125 kB). FLUGS specialist information service at the Helmholtz Zentrum München, German Research Center for Health and Environment, as of March 2004, p. 3.
- regard to chemical details, this section is again based on care disinfectants , with regard to spores on: Jörg Dressler, Peter Koger: Sporen und Sporizide - the special duel in the sterile area. Steriltechnik 1/2003, GIT Verlag, Darmstadt, pp. 29-32.
- disinfectant. In: Waste Manager Medicine. Retrieved October 15, 2019 (German).
- Publications / communications - Federal / State Working Group on Waste (LAGA). Retrieved October 15, 2019 .
- Evidence Ordinance (NachwV): Evidence for the disposal of waste. In: Waste Manager Medicine. Retrieved October 15, 2019 (German).
- The section on the risks of disinfectants primarily deals with the problem of domestic use as opposed to professional use in the medical and nursing field or in clean room technology . It is based on the presentation in: FLUGS: Hygiene and disinfection in clinics and households - an introduction , FLUGS specialist information service at the Helmholtz Center Munich, German Research Center for Health and Environment, as of March 2004.
- Daniel Bürgi, Lars Knechtenhofer, Isabel Meier, Walter Giger : Biocides as micropollutants in wastewater and water: prioritization of biocidal active ingredients . Study on behalf of the FOEN and ERZ , 2007 ( Download ( Memento from January 1, 2013 in the web archive archive.today ))
- Clean even cleaner . In: Der Spiegel . No. 37 , 1980 ( online ).
- GE Morfill, MG Kong, JL Zimmermann: Focus on Plasma Medicine. In: New Journal of Physics. 2009, Volume 11, Article 115011, doi: 10.1088 / 1367-2630 / 11/11/115011 , full text (PDF).
- Martin C. Klebes: Dermatological application of an electrical plasma at body temperature. Dissertation, Institute / Clinic for Dermatology, Venereology and Allergology of the Medical Faculty Charité - Universitätsmedizin Berlin, September 4, 2015, p. 16, full text (PDF).
- J. Heinlin, G. Isbary, W. Stolz, G. Morfill, M. Landthaler, T. Shimizu and others. a .: Plasma applications in medicine with a special focus on dermatology. In: Journal of the European Academy of Dermatology and Venereology: JEADV. (J Eur Acad Dermatol Venereol) 2011, Volume 25, No. 1, pp. 1-11, doi: 10.1111 / j.1468-3083.2010.03702.x .
- R. Walter, K. Büsching, H. Lausch: Water disinfection with full metal catalysts and hydrogen peroxide. In: Wasser, Boden, Luft: 1–2 / 2005, p. 30.
- Heinz Röttlich: Measures against Legionella in water. In: Environment magazine. Issue 1/2 2010, Springer-VDI-Verlag, Düsseldorf 2010.
- US EPA Filtration Guidance Manual . (PDF; 3.8 MB) water.epa.gov (English).
- Hazardous substances - sample lecture "Biocidal products and pesticides approval - especially risk assessment". (PDF) BAuA, accessed on April 16, 2017 .
- Disinfectants - a changing market . In: Management & Hospital compact. September 8, 2015, p. 10 f .; accessed on April 16, 2016.