The fact that cleanliness and disinfection contribute significantly to the prevention of diseases was already pointed out in the Old Testament, but the practical implementation of this knowledge has prevailed in the Western industrialized nations only since the late 19th century. Before that, not only private households but also hospitals were places where people often died due to infectious diseases that were actually preventable. Disinfection is an essential means of preventing the spread of pathogens.
What is disinfection?
Before any surgery, the surgical site is thoroughly disinfected to kill germs. Over the past 200 years, the number of infectious diseases has decreased massively, and infections are now among the less common causes of death. In addition to the general increase in cleanliness, disinfection has played a major role in this success. Disinfection is a special measure used to kill or at least render inactive viruses, germs, bacteria, spores and fungi that are present on an object or on living tissue, thus drastically reducing their number or activity so that the risk of an outbreak of an infectious disease in humans and animals becomes less likely. To achieve this antiseptic (i.e., germ-free) state, chemical and physical methods of disinfection are used.
Medical use, effect, goals
When using measures for disinfection, a distinction must be made between private households and a medical environment, because problems associated with disinfectants may well arise. In private households, disinfectants should generally not be used habitually. The substances sold freely in supermarkets and drugstores are usually not strong enough and are not always used properly (e.g., too little exposure time), so that, without the user being aware of it, particularly resistant strains of viruses and bacteria can be selected and become increasingly difficult to combat in the future. Another problem with the private use of disinfectants is that their constant application destroys the acidic protective skin mantle, which actually has the task of protecting the skin against the penetration of pathogens. Since private households do not have adequate disposal mechanisms for disinfectant liquids, substances that are harmful to the environment end up in sewage treatment plants, where they disturb the delicate balance of those species of bacteria that serve to treat water. To prevent disinfectants from causing lasting damage to skin and the environment and breeding antibiotic-resistant germs, disinfectants should be used primarily by trained personnel and only in a strategic manner. Therefore, the cleaning of private households should not aim at disinfection, but at minimizing microorganisms to a number that is not dangerous for healthy people.
Forms, types and species
There are different means and methods to achieve disinfection of objects and living tissues. In the medical, pharmaceutical, water treatment, and food sectors, these include physical methods (e.g., removal of air to create a germ-free vacuum, incineration, boiling or steaming with water at least 100°C hot, irradiation with ultraviolet light, filtering out pathogens, and radioactive irradiation) and the use of chemical agents to disinfect hands, linens, rooms, surfaces, and medical instruments. Chemical agents include alcohol, silver, mercury, ammonium salt, surfactants, peroxyacetic acid, iodine, chlorine, hydrogen peroxide, and formaldehyde. The above agents and procedures have three main objectives:
1. the damage of the outer cell membrane of the pathogens by dissolving out certain lipids (fats). 2. the damage of the spatial structure of their proteins. 3. the destruction of the genetic material by attacking their nucleic acids. For household use, in addition to normal surfactant-based household cleaners, so-called “natural” disinfectants such as alcohol, salt water, vinegar essence, citric acid and tea tree oil are suitable.
Risks, dangers, and side effects of omission
Although the overall number of infectious diseases has decreased significantly compared with previous eras when disinfection was unknown, between 7,500 and 15,000 patients still die each year in Germany alone from infections contracted in hospital. Every year, between 400,000 and 600,000 patients contract infections in connection with a medical intervention. The question therefore arises as to how these numbers can be reduced and whether sufficient hygiene measures are planned and also adhered to. Experts assume that up to one third of these infections could be avoided by adhering to hygiene rules. However, a particular problem, especially in German hospitals, is that resistant pathogens encounter patients with weakened immune systems. This circumstance leads to longer hospital stays on average, higher treatment costs and higher mortality rates than in neighboring countries. Resistant pathogens, however, are increasing in number. Causes for this, in both outpatient and inpatient settings, continue to be improper prescribing and use of antibiotics, which select and inadvertently breed pathogens, and a lack of disinfection, which further spreads pathogens.
