Disinfectants

Issues of Concern

The mechanism of action of disinfectants is different in microorganisms. However, the same technique is used to study these activities in bacteria, fungi, or viruses. Amongst all the microorganisms, antibacterial properties of disinfectants have been studied the most, while studying antiprotozoal are more inadequate due to limitation culturing in laboratory settings. Disinfectants target the virus envelope and their capsid and viral genome. One of the issues that were raised was the destruction of capsid releases of the viral genome. In some instances, these released nucleic acids from the capsid could be infective. Therefore, capsid destruction vs. further breakdown of the free nucleic acid should be considered in viral disinfection.[1]

Like antibiotics, there is a concern for the development of resistance to antiseptics and disinfectants. Therefore the use of the correct disinfectant is of high importance.[2] Prion proteins are normal proteins found on the surface of many cells and can cause brain damage once misfolded. These proteins are highly resistant to ordinary disinfectants, and there is no specific agent that can decontaminate the tissues infected by transmissible degenerative encephalopathies (TDE). [1][3]

To better understand the coverage of each disinfectant, some of the most commonly used disinfectants used a the hospital are as follow:

Alcohol has been widely used for hundreds of years as a disinfectant and antiseptic. Due to their lack of sporicidal activity are not recommended to be used for sterilization. They have a broad-spectrum antimicrobial activity that is due to membrane damage and cell lysis. To improve alcohol products' efficacy, they are sometimes mixed with emollients (decrease evaporation time) and with other biocides such as chlorhexidine (which remains on the skin longer than alcohol). [1]

Aldehydes: there are three essential classes of aldehyde disinfectants

• Glutaraldehyde is a dialdehyde that has bactericidal properties by binding to the outer layer of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), coverage against gram-negative bacteria, sporicidal property, fungal coverage, and potent virucidal agent.[1] Glutaraldehyde is routinely used to clean medical equipment such as endoscopes. The careful rinsing of these disinfectants from the medical equipment is used to prevent complications such as colitis post colonoscopy.[4][5][6]
• Formaldehyde is a monoaldehyde that is clinically used as a sterilant and disinfectant. Formaldehyde has the same coverage as glutaraldehyde (bactericidal, virucidal, and sporicidal) but works slower. It is crucial to know that formaldehyde reacts strongly with nucleic acid, and due to this reactivity, it is known to be a carcinogenic property of formaldehyde. Therefore proper personal protective equipment (PPE) and precautions should be taken while handling this substance.[1][7]
• O-Phthalaldehyde (OPA) is another potent bactericidal and sporicidal disinfectant that has similar coverage as glutaraldehyde is suggested to be a replacement for glutaraldehyde in endoscope disinfection.[8]

Anilides are rarely used in the hospital setting and have antiseptic properties, which makes them primarily used in soaps and deodorants have coverage against gram-positive and less on gram-negative or fungi.[9]

Biguanides: Chlorhexidine belongs to this family, has broad-spectrum activity, and is an antiseptic product. Chlorhexidine has a rapid (20 seconds) uptake by E. coli and S. aureus and is highly resistant to Mycobacterium. The Centers for Disease Control and Prevention (CDC) and the United Kingdom national evidence-based guidelines have made specific recommendations for using chlorhexidine to prepare the skin before central venous catheter insertion for children 2 months of age and older and for adults. However, there are no specific recommendations on the antiseptic of choice for infants less than 2 months of age.[10][11]

Diamidines: inhibiting oxygen uptake and induce leakage of amino acids. It has coverage against Pseudomonas aeruginosa (P. aeruginosa) and Enterobacter cloacae and is therefore used as topical treatment of wounds.[1]

Halogen-Releasing Agents

• Chlorine-releasing agents (CRA) are oxidizing agents that are highly active. Sodium hypochlorite is an example of CRA and is widely used as surface disinfectants (bleach) at home or in the hospital to disinfect surfaces contaminated with HIV or HBV. CRAs have sporicidal, bactericidal and virucidal.[12]
• Iodine-based agents are less reactive than chlorine but have a rapid rate of action. An example of these agents would be povidone-iodine which is used as an antiseptic and disinfectant for hundreds of years and is associated with extreme staining and skin irritation. Compared to CRAs, they are less active against fungi and spores.

Silver compounds: used to treat warts, eye infections, and burn wounds. Some of the more commonly used silver compounds are silver nitrate and silver sulfadiazine, which fight against Cryptococcus neoformans and P. aeruginosa.

Peroxygens

• Hydrogen peroxide (H2O2) is a well-known colorless liquid biocide widely used as a disinfectant, sterilant, and antiseptic in hospitals and homes. H2O2 is available in various concentrations and is believed to be environmentally friendly due to its degradation to oxygen and water. These compounds are highly active against gram-positive and gram-negative bacteria. They also have sporicidal activity at higher concentrations (10 to 30%).
• Peracetic acid (PAA) being a more potent biocide than H2O2 and has been used as medical devices, scopes, and hemodialyzers sterilants. In addition, they have activity against bacteria, viruses, and fungi at lower concentrations compare to H2O2.

Quaternary Ammonium Compounds (QAC) are used preoperatively as a skin antiseptic and can be applied to mucus membranes. QACs are also used in deodorants and disinfectants of hard surfaces.[13]

Clinical Significance

Hospital-acquired infections, also known as healthcare-associated infections (HAI), manifest 48 hours after admission to the hospital.[14] Some of the more persistent pathogens in the hospital setting are Clostridium difficile (C. diff.), vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA). 

The rate of these potentially deadly infections can be reduced by following precaution notice signs at the door, clear communication between the interprofessional teams, and proper education on which disinfectants are most effective on these pathogens. Familiarity with the different types of disinfectants and their coverage and proper use of each and scheduled cleaning could significantly reduce the HAI and improve patient outcomes.[15][16] [Level 1]

Nursing, Allied Health, and Interprofessional Team Interventions

When it comes to reducing the rate of HAI, it is imperative to understand that everyone in the healthcare setting, including physicians, nurses, pharmacists, lab technicians, and patients, has a crucial role in reducing the risk of transmission by proper cleaning, disinfecting, and using the appropriate PPE. Nurses by practicing guidelines are the center of this HAI prevention.[17] [Level 2]