Types of biocidal solutions used in hospitals for disinfection and sterilization
Chemical disinfectants used in hospitals are intended to kill bacteria, fungi, and contaminants, but these same substances also cause other problems. For this reason, it is always necessary to read product labels so that the appropriate biocidal product is used.
In all healthcare facilities, various chemical substances are used to disinfect surfaces or hands. Some of these chemicals are more effective against bacteria, germs, and spores than others, while some are less effective. Choosing the right biocidal product requires an understanding of how they work, as well as the advantages and disadvantages of the different types of chemical disinfectants used in hospitals.
Table of Contents
- Sterilization and high-level disinfectants
- Intermediate-level disinfectants
- Low-level disinfectants
- Factors to consider when choosing the right disinfectant
1. Sterilization and high-level disinfectants
Professional cleaning of medical spaces using high-quality disinfectants and products can help reduce the risk of healthcare-associated infections, which include infections associated with the use of contaminated medical devices such as syringes, catheters, and ventilators. Some common types of issues include bloodstream infections, urinary tract infections, and pneumonia.
For cleaning a medical center, biocidal products effective against a variety of bacteria, spores, germs, viruses, and microbes must be used. This is crucial for reducing health hazards and ensuring the proper and complete removal of germs from a facility.
Formaldehyde-based products
Formaldehyde—primarily available as a water-based solution called formalin, which contains 37% formaldehyde by weight—is used as a high-level disinfectant and sterilant. Formaldehyde exerts its bactericidal, tuberculocidal, fungicidal, virucidal, and sporicidal effects in an aqueous state, as well as in combination with low-temperature steam.
Formaldehyde has traditionally been used for the sterilization of equipment, such as surgical instruments and hemodialyzers, in combination with alcohols. Paraformaldehyde, a solid polymer of formaldehyde, is used in combination with low-temperature steam to disinfect heat-sensitive medical equipment.
Exposure risks and the potential carcinogenic effects of formaldehyde have recently limited its use in healthcare. However, next-generation aldehydes, such as glutaraldehyde and ortho-phthalaldehyde, with better sporicidal activity, a faster onset of action, and reduced exposure effects, have replaced formaldehyde in the disinfection manuals of most healthcare facilities.
Glutaraldehyde
Glutaraldehyde is a saturated dialdehyde widely used as a potent sterilant and high-level disinfectant. Its broad spectrum, which covers bactericidal, sporicidal, fungicidal, and virucidal activity, makes it an ideal biocidal product for the low-temperature disinfection and sterilization of critical and semi-critical equipment, such as endoscopes, dialyzers, and surgical instruments.
Glutaraldehyde is also mycobactericidal, and formulations of glutaraldehyde with phenols and alcohols have a better use-life while maintaining excellent microbicidal activity. Glutaraldehyde exposure must be monitored to ensure a safe working environment. Acute or chronic exposure, resulting in skin irritation, mucous membrane irritation, and multiple pulmonary symptoms such as occupational asthma and allergic rhinitis, has been reported in healthcare workers.
Ortho-phthalaldehyde
Since its introduction in 1999, ortho-phthalaldehyde has been accepted as a better and safer alternative to glutaraldehyde in most healthcare facilities. The substance has excellent microbicidal activity and superior mycobactericidal activity compared to glutaraldehyde. Furthermore, this biocidal product has strong bactericidal and sporicidal activity. Like glutaraldehyde, it interacts with amino acids, proteins, and microorganisms.
Ortho-phthalaldehyde has many advantages over glutaraldehyde, such as improved stability at different pH ranges, a lower risk of inhalation exposure, and a wider range of material compatibility, although it costs nearly three times as much. However, given the cost of sophisticated ventilation systems required to minimize respiratory risks associated with glutaraldehyde use, ortho-phthalaldehyde is more advantageous from a cost-effectiveness perspective.
Hydrogen peroxide
Disinfectant solutions containing 7.5% hydrogen peroxide are approved for sterilization and high-level disinfection in healthcare settings. Its good properties, with a broad spectrum of bactericidal, virucidal, sporicidal, and fungicidal action, combined with its excellent stability and eco-friendly characteristics, have made hydrogen peroxide the preferred disinfectant for semi-critical and non-critical equipment. At the same time, this biocidal product is an ideal surface disinfectant.
Despite not being listed as compatible with equipment by all endoscope manufacturers, hydrogen peroxide-based disinfectant solutions are still considered ideal alternatives to other toxic sterilants, such as ethylene oxide and aldehyde-based disinfectants.
Peracetic acid
Another emerging alternative to ethylene oxide and aldehyde-based sterilizers is peracetic acid. Peracetic acid-based solutions are considered to be a more powerful disinfectant than hydrogen peroxide. They are sporicidal, bactericidal, virucidal, and fungicidal at low concentrations and, very importantly, they are eco-friendly. They have replaced traditional disinfectants for medical devices, endoscopes, and hemodialyzers.
Peracetic acid-based solutions are also used as an environmental surface sterilant and behave similarly to other oxidizing agents. For this reason, they disrupt cell wall permeability and oxidize sulfhydryl and sulfur bonds in proteins, enzymes, and other metabolites.
2. Intermediate-level disinfectants
Sodium hypochlorite
Chlorine-releasing agents, the most popular being sodium hypochlorite solution, are widely used for disinfecting hard surfaces. Sodium hypochlorite is effective for disinfecting surfaces contaminated with the human immunodeficiency virus or hepatitis B virus.
Sodium hypochlorite has also been designated as the best defense against Clostridium difficile infections acquired in hospitals and the community. With a broad spectrum of antimicrobial activity, sodium hypochlorite is inexpensive and has low toxicity.
Chlorine, like other biocidal products, is highly active and destroys cellular protein activity. Hypochlorous acid, the active fraction, has been shown to have harmful effects on bacterial DNA through the formation of chlorinated derivatives of nucleotide bases. High concentrations of sodium hypochlorite exhibit significant levels of sporicidal and virucidal activity.
Iodophors
Iodophors, complexes of iodine and a solubilizing agent or carrier, are used as antiseptics and surface disinfectants. Iodine has bactericidal, fungicidal, tuberculocidal, virucidal, and sporicidal properties, while its antiseptic properties are well-known.
Iodophors, such as povidone-iodine and poloxamer-iodine, are much more stable, have fewer irritating characteristics, and exert better microbicidal action than aqueous iodine solutions.
3. Low-level disinfectants
Low-level disinfectants are one of the most common methods for cleaning and disinfecting surfaces. These biocidal substances can destroy most bacteria, some fungi, and some viruses within a certain period of time (less than ten minutes).
Alcohol
Alcohols have rapid bactericidal properties, in addition to fungicidal and virucidal ones, but they do not kill bacterial spores and are therefore not a biocidal product. The appropriate concentration for the antibacterial activity of alcohols is between 60 and 90 percent, and if diluted to a concentration of 50% or less, its effectiveness decreases.
Methyl alcohol (methanol) has the weakest antibacterial effect among alcohols and, therefore, is rarely used in health centers and hospitals. Ethyl alcohol is a powerful virucide in concentrations of 60 to 80 percent. Thus, it deactivates all lipophilic (fat-loving) viruses, such as the influenza virus and many hydrophilic viruses (such as adenovirus, enterovirus, rhinovirus, and rotavirus), but does not affect the hepatitis A virus or the poliovirus.
Isopropyl alcohol is not active against non-lipid-enveloped viruses, but it is fully active against lipid-enveloped viruses. Studies have also shown the ability of ethyl and isopropyl alcohol to deactivate the hepatitis B virus (Source).
Alcohols are used effectively for disinfecting oral and rectal thermometers but are not recommended for the sterilization of medical and surgical materials because they cannot penetrate protein-rich substances. Many fatal infections occur after surgeries when alcohols have been used to sterilize surgical instruments contaminated with bacterial spores.
Phenols
Phenolic disinfectants destroy the cell membranes of microorganisms. They have bactericidal, fungicidal, and virucidal effects, but are ineffective against some bacteria such as Clostridium difficile. Due to the efficacy rate of phenols, they are used for the disinfection of low-sensitivity equipment and treatment rooms.
Quaternary ammonium compounds
Quaternary ammonium compounds are used for various clinical purposes, such as preoperative disinfection and the disinfection of insensitive devices, as well as cleaning surfaces and removing odors from them. This disinfectant has antibacterial, antifungal, and antiviral properties.
4. Factors to consider when choosing the right disinfectant
In a hospital environment, there will likely be several different types of disinfectants, and it is always important to choose a biocidal product, disinfectant, or sterilant, as appropriate. To prevent nosocomial infections, it is recommended to consider the following factors when choosing a product.
- Safety: implies the risk of exposure for employees and patients to the surrounding environment.
- Surface type: porous or non-porous.
- Surface compatibility: consider how well the disinfectant acts on certain surfaces and materials.
- Target microorganisms: certain microbes (such as HIV, hepatitis, and C. difficile) may require different disinfectants.
- Ease of use and cost: both are major factors in choosing the right disinfectant for a hospital.
Klintensiv Tip: It is always essential to use products that are specifically designed and approved for the job at hand. Klintensiv meets hospital needs with a wide range of disinfection, cleaning, and sterilization products.
Conclusion
Chemical disinfectants used in hospitals are classified into three categories: high-level, intermediate-level, and low-level. High-level effect types destroy many microbes. For this reason, they are commonly used in sensitive medical cases. Although low-level efficacy types are widely used, they are only effective for cases with low medical sensitivity. Which disinfectant is the best depends on a variety of factors, from the type of environmental contamination and its sensitivity to the extent of the impact on medical staff. Knowing these and becoming familiar with their performance can be of great help in choosing the best one.
Sources:
https://www.hospitalmanagement.net/features/featureppc-disinfectants-hai-globaldata/?cf-view
https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/chemical.html
https://monib-health.com/en/post/91-chemical-disinfectants-used-in-hospitals
