ENVI RONMENTAL DECONTAMINAT ION
decontamination efficacy of HPV in different conditions.
Increased cleaning efforts – law of the instrument Another critical challenge that hasn’t been investigated on a larger scale, is the increased use of biocides, disinfectants and other chemicals as a form of enhanced cleaning to disinfect surfaces and equipment within a healthcare setting. Since the start of the pandemic, healthcare sectors and global health organisations, including the World Health Organization (WHO), urged hospitals and other healthcare settings to increase the use of cleaning products and cleaning hours in order to reduce rates of transmission. Surfaces are known to be one of the main vectors of transmission of infections in healthcare settings and contribute to increased rates of healthcare-associated infections (HCAIs) due to the stability of certain microorganisms on surfaces and equipment including methicillin resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Clostridium difficile (C.diff) and other pathogenic microorganisms.4 In addition, many research papers have shown the stability of SARS-CoV-2 on dry surfaces that can remain infective for days under indoor ambient conditions, which may have led to many outbreaks in healthcare settings during the ongoing pandemic.5
As
a result, healthcare sectors globally have emphasised the importance of increasing cleaning measures by using more effective, instant-kill disinfectants and cleaning formulas and increasing cleaning hours. According to its efficiency and ability
to kill microorganisms, including bacterial spores, a disinfectant or antimicrobial product can belong to one of four distinct groups: sterilant or high-, intermediate- and low-level disinfectant. Examples of these include: heat and steam, hydrogen peroxide and peracetic acid for high-level disinfectants, hypochlorite and iodophors for intermediate-level disinfectants, and phenolics and quaternary ammonium compounds for low-level disinfectants. In addition, other innovative methods may also have an impact on surfaces such as ethylene oxide, ozone, hydrogen peroxide vapour and ultraviolet (UV) light.6 It is vital to make sure that surfaces are compatible with the chemical products being used to ensure minimum surface damage. Heavy application of these chemicals to contaminated surfaces over time may result in decolouration, increased roughness, and, as a consequence, formation of cracks and fractures, that can lead to reduced efficacy of cleaning protocols. Increased surface roughness can provide small spaces that are difficult to access and clean. A rough surface has more hiding spaces for microbes where they evade cleaning and disinfection, making it more difficult for the staff to disinfect these obscured cracks and fractures. These tiny spaces sometimes can barely be noticed and can contribute to challenges for infection control and prevention measures. Microorganisms are very small in size; bacteria (0.1µm-50µm); fungi (0.5µm-20µm); viruses (2nm- 400nm).7
A surface roughness diameter of a micro or nanoscale (i.e., 10nm) would be more than enough to allow contamination to occur. Large grooves are tens of micrometres
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wide and more than 500 nm deep. Nanoscale grooves and trenches have a depth larger than 30 nm and width smaller than 1 µm. Therefore, these chemicals, when used constantly and intensively as a way to enhance infection control measures, can over time reduce the surface quality, forming nooks and crannies (cracks and fractures) that allow pathogenic microorganisms to reside and multiply – basically forming new reservoirs and increase the risk of contamination, which adds to the ongoing problem of contamination with SARS-CoV-2 and other harmful microorganisms. These cracks can be more difficult to decontaminate using disinfection technologies such as UV-C light systems – which relies on the direct exposure of light on the target surface and, in this case, the light fails to reach these cracks. Also, it has been shown that increased surface roughness is associated with increased adhesion of microorganisms and formation of biofilms. Adhesion is known to be the first step in biofilm formation and biofilms, once formed, can be very difficult to remove using biocides and other anti-microbials agents.
Surfaces compatibility
While manufacturers may test compatibility of their product with generic chemicals such as alcohol or acids, they are unlikely to have tested all the disinfectants that they may encounter. Multiple factors must be considered when evaluating chemical compatibility, including: type and concentration of the reagent, exposure temperature and time, residual or applied stress on the fabricated part, and surface characteristics. For instance, stainless steel surfaces are used widely in hospital settings
MAY 2021
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