Disinfection - Procedure, Techniques, and Its Importance

What Is Disinfection?

Disinfection is a process that aims to eliminate a significant number of harmful microorganisms on inanimate objects, excluding bacterial spores. This is frequently done in healthcare settings using liquid chemicals or wet pasteurization. The effectiveness of disinfection can be influenced by various factors that may reduce or impede its efficacy. Sterilization is different than disinfection. Any type of microbial life, including spores, must be destroyed or removed through the process known as sterilization.

These factors include the cleanliness of the object before disinfection, the presence of organic and inorganic matter, the type and level of microbial contamination, the concentration and duration of exposure to the disinfectant, the characteristics of the object (such as crevices, hinges, and lumens), the presence of biofilms, the temperature and pH conditions during disinfection, and in certain cases, the humidity during sterilization processes, as observed with ethylene oxide (ETO) sterilization.

What Are the Steps Involved in the Typical Disinfection Process?

The steps involved in the typical disinfection process include the following:

• Disinfectant Selection: The initial step is to choose an appropriate disinfectant. Disinfectants must be used in accordance with the instructions on their approved labels, including the recommended dilution, application method, contact time, and safety precautions.

• Disinfection Preparation: Fresh solutions of disinfectants should be prepared daily or as indicated on the product label. Some disinfectants may lose stability shortly after preparation or when stored for extended periods. Using an expired product can result in ineffective disinfection. Furthermore, using disinfectants at higher concentrations than recommended can increase hazards to personnel and the environment, while over-dilution may render the process ineffective against the target microorganism.

• Application: Disinfectants should only be used on the specific items or areas mentioned on the label. The appropriate application method and contact time will be provided. Application methods may include spraying, fogging or misting, wiping, immersing, or mop-on techniques.

• Contact Time: Adequate contact time is one of the most critical aspects of the disinfection process, regardless of the chosen method. Sufficient contact time is necessary for the desired effect of microbial destruction.

• Rinse: After application, thorough rinsing of items and areas is recommended. Many chemical disinfectants can be harmful to animals, and therefore rinsing with potable water is important.

• Drying: Whenever possible, surfaces should be allowed to dry completely, ideally overnight. This involves keeping the area free of animals or activity for a specific period, allowing complete drying, and facilitating further reduction or elimination of any remaining microorganisms through desiccation.

What Are the Different Techniques Used for Disinfection?

There are several different techniques used for disinfection, each with its own strengths and applications. These techniques are employed based on factors such as:

1. The type of microorganisms being targeted.

2. The nature of the surfaces or objects being disinfected.

3. The specific requirements of the environment.

The reduction, inactivation, or destruction of pathogenic microorganisms can be accomplished through the use of physical (such as heat or ultraviolet light) or chemical (such as disinfectants) processes, which are described below:

• Chemical Disinfection: This type involves the use of chemical agents to destroy or inactivate microorganisms. Different types of disinfectants are available, each with varying effectiveness against specific pathogens. Some commonly used chemical disinfectants include:

  1. Chlorine-Based Disinfectants: Chlorine compounds, such as sodium hypochlorite (bleach), are highly effective against a wide range of microorganisms. They are commonly used in healthcare facilities, water treatment plants, and household settings. Aqueous solutions of sodium hypochlorite that range in concentration from 5.25 percent to 6.15 percent, also known as household bleach.

  2. Quaternary Ammonium Compounds: These compounds are often used as disinfectants in healthcare settings and households. They are effective against many pathogens but may be less effective against certain viruses.

  3. Alcohol-Based Disinfectants: Alcohol-based solutions, such as ethanol or isopropyl alcohol, are widely used for disinfecting hands and skin. They are virucidal, fungicidal, and tuberculocidal in nature. However, they do not eradicate bacterial spores. The optimal bactericidal concentration is between 60 percent and 90 percent solutions in water because their cidal activity rapidly decreases under 50 percent concentration.

  4. Superoxide Water: A new disinfectant called ‘super oxidized water’ has been studied for its microbicidal properties. The idea of electrolyzing saline to produce a disinfectant or antiseptic is intriguing because the raw materials, saline, and electricity, are cheap, and the final product, water, has no negative environmental effects. As with any germicide, the concentration of the active ingredient (available free chlorine) has a significant impact on the antimicrobial activity of superoxidized water, which is another name for electrolyzed water.

  5. Glutaraldehyde: This compound is commonly used as a high-level disinfectant in the medical field, particularly for sterilizing various medical equipment. These include endoscopes, endocavitary probes, spirometry tubing, dialyzers, transducers, anesthesia, and respiratory therapy equipment, and others. One of the advantages of glutaraldehyde is that it is non-corrosive to metal and does not cause damage to lensed instruments, rubber, or plastics. The labels approved by the FDA (Food and Drug Administration) for high-level disinfection using 2 percent or higher concentration of glutaraldehyde at 25 degree Celsius specify a range of 20 to 90 minutes of contact time.

  6. Hydrogen Peroxide: When applied to inanimate surfaces, commercially available 3 percent hydrogen peroxide proves to be a reliable and efficient disinfectant. Its stability and effectiveness have been demonstrated in various settings. Concentrations ranging from three percent to six percent have been utilized for disinfecting soft contact lenses, with a typical duration of two to three hours using 3 percent hydrogen peroxide. Additionally, hydrogen peroxide has been successfully employed in disinfecting ventilators, endoscopes, and fabrics. This compound has shown effectiveness in spot-disinfecting fabrics within patients' rooms.

• Hot-Water Pasteurization: Pasteurization using high-temperature water is a viable alternative to chemical disinfection for respiratory therapy and anesthesia equipment. It typically requires a time-temperature combination exceeding 70 degrees Celsius for a duration of 30 minutes.

• Ultraviolet (UV) Disinfection: Ultraviolet disinfection utilizes UV light to destroy or inactivate microorganisms. UV light damages the DNA (deoxyribonucleic acid) or RNA (ribonucleic acid) of microorganisms, preventing them from replicating and causing infection. This technique is commonly used in healthcare facilities, water treatment plants, and air purification systems.

• Heat Disinfection: This type involves the use of high temperatures to kill or inactivate microorganisms. This technique is commonly employed in healthcare settings, laboratories, and food processing industries.

• Ozone Disinfection: Ozone is a powerful oxidizing agent that can be used for disinfection purposes. It is effective against bacteria, viruses, and fungi. Ozone disinfection is commonly used in water treatment plants, swimming pools, and air purification systems.

• Plasma Disinfection: It is an emerging technique that uses low-temperature plasma to kill or inactivate microorganisms. Plasma generates reactive species that destroy the microorganisms' cell walls and genetic material. This technique is being explored for various applications, including medical equipment sterilization and air purification.

What Is the Importance of Disinfection?

Disinfection serves several important purposes, which include:

• Prevention of Diseases: The primary purpose of disinfection is to prevent the transmission of infectious diseases. By eliminating or inactivating pathogenic microorganisms, disinfection helps break the chain of infection and reduces the risk of spreading illnesses from contaminated surfaces, objects, or air.

• Healthcare-Associated Infection (HAI) Control: Disinfection plays a critical role in healthcare settings to prevent healthcare-associated infections. Proper disinfection of surfaces, medical equipment, and instruments help create a safe environment for patient care and reduces the risk of infections acquired during medical procedures.

• Food Safety: Disinfection is essential in the food industry to ensure food safety. Contaminated food can harbor harmful microorganisms that cause foodborne illnesses. Proper disinfection techniques, such as sanitizing surfaces, utensils, and food preparation areas, help eliminate bacteria and viruses, reducing the risk of foodborne diseases.

• Public Spaces and Facilities: Disinfection is crucial in maintaining clean and safe public spaces, including schools, offices, gyms, public transportation, and recreational facilities. Regular disinfection of commonly touched surfaces, such as doorknobs, handrails, and shared equipment, helps reduce the transmission of pathogens and creates a healthier environment for individuals.

• Water and Wastewater Treatment: Municipal water treatment plants use disinfection techniques, such as chlorination, UV (ultraviolet) disinfection, and ozonation, to ensure that the water supplied to households is free from harmful microorganisms. Disinfection of wastewater before it is released back into the environment also helps prevent the contamination of water sources.

• Air Quality Improvement: Airborne pathogens can pose a significant risk to human health, particularly in enclosed or crowded spaces. Disinfection techniques, such as UV germicidal irradiation (UVGI) and air filtration systems, help inactivate or remove microorganisms from the air, reducing the spread of airborne diseases and improving indoor air quality.

• Pandemic Preparedness: During pandemics or outbreaks of infectious diseases, proper disinfection practices become even more critical. Disinfection, along with other preventive measures like hand hygiene and social distancing, plays a crucial role in slowing down the spread of diseases, protecting vulnerable populations, and minimizing the impact of the outbreak on public health.

Conclusion:

Disinfection is crucial to public health strategies because it helps keep environments safe and prevent the spread of infectious diseases. Microorganisms can be effectively removed or rendered inactive using various methods, such as chemical disinfection, heat disinfection, and UV disinfection. To safeguard people and communities from the threat of communicable diseases, disinfection must be prioritized as part of daily routines, particularly during pandemics.