According to the Law “On Ensuring the Sanitary and Epidemiological Welfare of the Population,” the organization and implementation of disinfection measures is one of the main components in the complex fight against and prevention of infections. This is primarily due to the following factors: the presence of unfavorable trends in the increase of infectious diseases (HIV infection, tuberculosis, chronic parenteral viral hepatitis, and others); the continuous rise over recent years in the risk of nosocomial (hospital-acquired) infections; the real possibility of transmission of especially dangerous infections from other countries and territories; disinfection and sterilization have been, are, and will remain the most affordable, accessible, and, most importantly, reliable means of prevention.

Disinfection measures conducted in healthcare facilities include preventive and focal disinfection.

When cases of infectious diseases or epidemiologically dangerous carriage of pathogens arise in healthcare institutions, focal (current and final) disinfection is required. This is carried out to prevent the spread of infection beyond the focal area. The choice of disinfectant and the mode of its application depend on the type and properties of the pathogen.

Preventive disinfection is a set of disinfection activities conducted in the absence of infectious diseases, aimed at preventing the emergence and spread of infections. It is performed daily and includes the decontamination of various objects in the healthcare environment (medical devices, room surfaces, furnishings, medical instruments and equipment, etc.); antiseptic treatment of the skin surface of healthcare personnel’s hands and the surgical and injection fields of patients; and decontamination of medical waste.

General cleaning in healthcare departments also serves a preventive purpose. It is carried out on a planned schedule approved by the medical facility’s director. The frequency of general cleaning depends on the function of the premises and in accordance with applicable regulatory documents.

For disinfection in healthcare facilities, disinfectants from various chemical groups may be used; they must be registered, certified, and approved for use by the Ministry of Health and have appropriate instructions for use.

At the present stage, thousands of chemical compounds with biocidal activity are known, but only hundreds are practically applicable. Many biocidal agents are not permitted for production or discontinued due to low antimicrobial activity, high toxicity, or environmental contamination risks.

Recently, significant progress has been made in the creation and production of disinfectants. Special attention is given to developing multi-component formulas where active substances are combined in optimal ratios, offering a broad spectrum of antimicrobial activity that ensures the destruction of viral and bacterial pathogens (including vegetative and spore forms). Incorporating new modified components synergistically enhances antimicrobial activity and improves cleaning properties, such as odor, without damaging the structural materials of treated objects. Hand antiseptics for medical personnel’s skin always include substances that protect the skin during prolonged use.

Advances in medical technologies and the introduction of new fine instruments and products made from precious metals, polymer materials, and optics, which cannot be disinfected by physical factors (temperature, pressure, radiation), require the use of increasingly effective special chemical formulations that do not cause adverse reactions with medical materials even after prolonged contact.

Several types of chemical disinfectants are distinguished: halogen-containing compounds, peroxide compounds, aldehydes, guanidine-structured compounds, alcohols, phenols, acids, quaternary ammonium compounds (QACs), and tertiary amines. Each has its own antimicrobial spectrum.

Phenolic compounds are an anachronism in disinfectants due to excessive toxicity and destructive action and are considered hazardous to human health. The use of phenol in disinfectant formulations should be completely abandoned.

Halogen-containing compounds’ active components are chlorine, iodine, or bromine.

Chlorine-containing preparations such as sodium hypochlorite, sodium salt of dichloroisocyanuric acid, trichloroisocyanuric acid, and dichloramine are most frequently used. These compounds have broad antimicrobial action, deodorizing and bleaching effects, and the ability to homogenize. Some chlorine-active substances, although cheap and traditionally used for decades, have drawbacks: strong unpleasant odor, corrosiveness, low water solubility, toxicity, instability during storage, reduced activity in the presence of organic substances (including proteins), corrosive effect on metals, and weakening of fabric strength. They are also a major source of highly toxic dioxins formed in combination with many aromatic compounds, especially phenols, causing serious environmental harm when released.

To reduce the corrosive effect of chlorine-based agents, corrosion inhibitors are added, and surfactants provide cleaning properties.

Modern chlorine-based agents, primarily those based on dichloroisocyanuric acid and derivatives, usually have composite or improved formulations that significantly reduce these negative effects, allowing use for disinfecting a wide range of objects. Scientific research and practical application confirm these agents are more active against viral pathogens and bacterial spores compared to chlorine lime or chloramine.

Chlorine agents are mainly used for disinfecting corrosion-resistant surfaces, sanitary equipment, linens, cleaning tools, and disposable medical devices. They are also preferred for disinfecting water, drinking water containers, and food products.

Iodine preparations have pronounced antibacterial, antiviral, and antifungal effects but lack sufficient activity against some bacteria. Their disadvantages include skin and mucous membrane irritation, potential to cause burns, reactions, and irritations. Iodine is poorly soluble in water, volatile, and quite toxic.

Recently, iodophors — complexes of iodine with water-soluble polymers — have become widely used. Iodophors, especially povidone-iodine, retain iodine’s antiseptic properties without most of its drawbacks (i.e., they do not irritate or burn skin or mucous membranes, do not cause reactions or irritations, and accelerate repair and healing). They also have cleaning properties, enhancing the disinfection process. Iodophors maintain high bactericidal activity even in the presence of organic substances like proteins, blood, and pus. The bactericidal effect of iodine in this complex is prolonged compared to inorganic iodine compounds. Iodine and iodophors are primarily used as antiseptics for skin and mucous membranes.

Peroxide compounds, mainly hydrogen peroxide, have a broad antimicrobial spectrum and are environmentally safe. However, disadvantages include chemical burns upon skin contact, strong irritation of mucous membranes, tissue and fabric discoloration, and metal corrosion. Hydrogen peroxide solutions are unstable, complicating transport, storage, and use. Nonetheless, this group is very promising, especially when combined with other chemicals and corrosion inhibitors to create stable, effective, and less harmful disinfectants.

These agents are used to disinfect surfaces in rooms, furniture, equipment, medical instruments, sanitary equipment, laboratory glassware, and care items. Peroxides and peracids are also used for chemical sterilization of heat-sensitive medical devices and instruments.

Aldehydes widely used as active components in disinfectants include formaldehyde, glutaraldehyde, succinaldehyde, glyoxal, and ortho-phthalaldehyde.

Aldehydes are valuable due to broad antimicrobial activity against almost all microorganism types and forms and no harmful effects on objects. However, they fix protein contaminants (e.g., sputum and mucus) on surfaces, requiring thorough cleaning before disinfection. They are also highly toxic, limiting their use on surfaces, linens, and utensils. Inhalation exposure is a significant risk for workers, so composite formulations with aldehydes bound to other compounds (e.g., polyguanidines) are important as they retain positive properties but reduce toxicity.

This class is used for disinfecting and sterilizing medical devices, including surgical and dental instruments and both rigid and flexible endoscopes.

Alcohols include ethanol, 1-propanol, 2-propanol (isopropanol), and phenoxypropanol. They are environmentally safe and relatively non-toxic but lack sporicidal properties.

Alcohol-based products are used for disinfecting small surfaces, equipment, furnishings, instruments, and hard-to-reach objects that require rapid disinfection and drying. They are also primary components of skin antiseptics.

Inorganic acids have stronger and broader antimicrobial action than organic acids but are not used in healthcare disinfection due to toxicity to humans.

Organic acids such as glycolic, citric, malonic, and lactic acids are used for treating hemodialysis equipment. Some acids are components of complex antiseptics. Peracetic acid has high antimicrobial properties, even against bacterial spores.

These acids are used for chemical sterilization but their aggressive action on materials and solution instability must be considered.

Quaternary ammonium compounds (QACs) include active substances such as Catamine AB, didecyldimethylammonium chloride, dioctyldimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, and hexadecyltrimethylammonium chloride.

QACs have many valuable properties: low toxicity, environmental and hygienic safety, detergent properties, and sufficient bactericidal efficacy against a wide range of Gram-positive and Gram-negative bacteria. However, increasing QAC concentration raises destructive effects on surfaces and negatively affects human health. They are effective against causative agents of intestinal and droplet bacterial infections, fungi, and some viruses but have limited activity against Proteus and Pseudomonas species and may promote resistant strains. QACs have little or no effect on Mycobacterium tuberculosis, bacterial spores, and hydrophilic viruses. Therefore, QAC-based disinfectants are suitable only for limited objects. In the US, Japan, and Europe, QAC-based agents are banned for disinfecting instruments and endoscopes and remain relevant mainly for healthcare environment items and the food industry.

Combined with other active substances, QACs form interesting and promising compounds. For disinfecting and pre-sterilization cleaning of medical instruments, composite agents including QACs are advisable. Such disinfectants do not fix organic contaminants but instead clean surfaces.

Guanidine-structured compounds include polyhexamethylene guanidine chloride, polyhexamethylene guanidine phosphate, and chlorhexidine bigluconate. Polyguanidines are a promising modern disinfectant group with low toxicity, high stability, and no damage to treated objects. These substances form films on surfaces, providing prolonged residual bactericidal action.

They are used for disinfecting various surfaces and medical devices. Guanidine-based antiseptics are also used for treating mucous membranes, skin, and adjacent human tissues.

Tertiary amines (amphoterics) have a broad antimicrobial spectrum, including bactericidal, virucidal, and fungicidal properties. They are especially active against tuberculosis pathogens and have good detergent and cleaning properties. However, many scientists note their potential to cause reactions and irritation, limiting or excluding their use in the presence of patients or visitors. Scientific opinions on their use for chemical sterilization are ambiguous. Currently, tertiary amine-based disinfectants are not permitted for high-level disinfection or sterilization in Europe, Japan, or the USA.

Tertiary amine-based agents are used for disinfecting medical devices compatible with pre-sterilization cleaning, as well as various surfaces and equipment.

Combined disinfectants, depending on their active ingredients (QACs, QACs + aldehydes, QACs + tertiary ammonium compounds, QACs + guanidine derivatives, guanidine derivatives + peroxide compounds, peroxide compounds + guanidine derivatives, etc.) and functional additives (corrosion inhibitors, pH regulators, etc.), may be used for surfaces, furniture, medical device disinfection, and disinfection compatible with pre-sterilization cleaning.

Combining different active components ensures a broad antimicrobial spectrum. Modern manufacturers use chemicals from independent active groups that synergistically enhance antimicrobial action.

Priority criteria for selecting disinfectants include: antimicrobial spectrum and thus efficacy; human health and environmental safety; economic factors (cost-effectiveness); and absence of damage to materials of medical devices and equipment.

An important issue in effective disinfectant use is preventing resistance formation in some microorganisms, primarily nosocomial infection pathogens, during long-term use. Resistance development speed depends on microorganism type and disinfectant properties. Resistant strains appear faster with QACs, while aldehyde-based agents see such resistance much less frequently.

Worldwide, to prevent resistant strains in healthcare settings, disinfectants with different active substances are rotated.

Experts note that creating a quality disinfectant is a complex process lasting several years, from recipe selection (often based on proven formulas) to multi-stage practical testing.

Given healthcare facility funding, managers often prioritize disinfectant cost. However, purchasing a quality product considering use cases, antimicrobial spectrum, toxicity, cleaning properties, and usage conditions ultimately yields greater economic benefit. The most expensive disinfectant is the one that does not work but pollutes the environment and harms staff and patients’ health.