BSEE-OCT21-PG34 feature.qxp_Layout 1 14/09/2021 11:47 Page 34
BSEE
‘Ewater’ – a better solution for healthcare disinfection
Adrian GeeTurner from L’Eau and Gary Driscoll from Portsmouth AQUA explain why Ewater (electrolysed water/hypochlorous acid) has advantages over traditional disinfectants in a wide range of healthcare applications. Both companies are exhibiting at The Healthcare Facilities Management conference and exhibition at the NCC in Birmingham on 12 October 2021, where one of the event’s recurring themes will be disinfection strategy
D
isinfection strategy will also be
addressed by one of the conference speakers, Professor Stephanie Dancer,
who will deliver a presentation entitled: ‘Smart cleaning: the best defence against hospital- acquired infection’.
Background
Cleaning is the physical removal of soil and microorganisms from surfaces, which may also involve the action of a surfactant, catholyte, detergent or water. Cleaning should be undertaken prior to disinfection because the presence of organic soil will reduce the effectiveness of disinfectants.
Disinfection is the process by which most or all of the pathogenic microorganisms are deactivated or killed. Internationally accepted standards have been created to define the levels of deactivation that are necessary for different microorganisms in different applications. Sterilisation refers to the process which kills all forms of microbial life and is predominantly used for the decontamination of surgical instruments.
Professor Dancer advocates the physical removal of soil and pathogens rather than obliteration for routine cleaning but accepts that there are circumstances where disinfectants are necessary in the healthcare environment. She says: “The challenge is to find a product that is effective, quick-acting, non- toxic to people and the environment; and, for the NHS in particular, it must be cheap. Electrolysed water (hypochlorous acid) is a potential choice for hospitals and other healthcare organisations.”
A wide variety of disinfectants are commercially available; the majority of which are toxic to both microorganisms and humans. This toxicity represents a safety hazard during use and storage, as well as, in some cases, an environmental threat. Interest is therefore growing rapidly in products that are able to deliver superior (verified) levels of efficacy, but without toxicity to users and the potential for environmental harm. Electrolysed water meets these requirements but has not been universally adopted because past products quickly reverted to the original ingredients – salt and water. However, a small number of manufacturers have recently developed processes that have resolved this issue and it is now possible to purchase E-water with a 12-month shelf-life or longer.
Ewater – what is it? For the purposes of disinfection, the
active ingredient of E-water is hypochlorous acid (HOCl) in an aqueous solution which is
approximately pH neutral. It does not contain any substances that are hazardous to human health, so there are no COSHH requirements and no personal protective equipment (PPE) is necessary when handling the ready-to-use liquid. The end products from the practical deployment of HOCl are salt and water.
The effectiveness of the market’s leading e-Water products has been tested according to international standards such as EN 1276, EN 14476 and EN 13704 against the most common pathogens, with most demonstrating impressive Log-6 effectivity against bacteria, Log-4 against viruses and Log-3 against spore-forming bacteria.
Comparison with
traditional disinfectants It is very important to differentiate between e-Water (Hypochlorous Acid) and household bleach (Sodium Hypochlorite). Bleach formulations dissolve in water to create a dilute aqueous chlorine solution in which undissociated hypochlorous acid (HOCl) is active as the antimicrobial compound. Bleach denatures protein in micro- organisms and is therefore effective at killing bacteria, fungus and viruses. As an irritant to skin, bleach can cause burns and serious damage to eyes. Inhalation of its fumes can harm the respiratory tract, and the correct concentration of bleach must be used to achieve effective disinfection. Most bleach manufacturers claim 99.9% kill (Log- 3) of harmful micro-organisms, so e-Water can claim to be one thousand times more effective. This means that bleach could be expected (in the right conditions) to reduce one million colony forming bacterial units (CFUs) to 1,000 CFUs whereas a Log-6 disinfectant (such as e-Water) would be expected to reduce the same size colony down to just one single CFU. Bleach is therefore mainly suitable for the low- cost disinfection of non-porous, unpainted surfaces such as floors and toilets.
Quaternary ammonium
compounds (Quats) are widely used in cleaning and disinfection product formulations. Quats are positively- charged (cationic) surfactants that can be effective against bacteria, fungi and enveloped viruses. They also provide detergent activity, so they are suitable for cleaning purposes, and are frequently included in the formulations of household and industrial products. The activity of Quats can be adversely affected by water hardness, fat-containing substances, absorbent materials and anionic surfactants. The labels of Quat products generally contain health warnings and since they contain hazardous substances, Quats represent a threat to the environment, so used containers should be incinerated or disposed of in an acceptable permitted waste disposal facility.
The US National Toxicology Program, NIOSH, and OSHA have each determined that the acceptable Occupational Exposure Level (OEL) for quaternary ammonium compounds and for bleach – is zero.
Quats have become popular because they provide an opportunity to formulate disinfectants to target specific pathogens in specific applications,
34 BUILDING SERVICES & ENVIRONMENTAL ENGINEER OCTOBER 2021
especially where detergent action is also required. However, given the limitations outlined above, e-Water represents a superior alternative.
Application for inclusion in the 2021 WHO
Essential Medicines List Towards the end of 2020, Dr. Eric Rasmussen, Briotech's chief medical officer, made an application to the World Health Organisation proposing the inclusion of Hypochlorous Acid (HOCl) for disinfection, antisepsis, and wound care. In response, the WHO recommended further, larger clinical trials, but the submission contains information that is pertinent to this article:
HOCl has emerged in the current pandemic as the most potent and environmentally safe disinfectant available and with a wide range of efficacy against many human pathogens, including the SARS-CoV- 2 coronavirus. In recent years compelling evidence of the potency of pure, stable preparations of HOCl in the inactivation of even the most resistant infectious agents, such as BSE Prions and HPV16 viruses (both of which are completely unaffected by disinfectants currently on the EML list) has made it clear that HOCl deserves a place in every public health programme as a
fundamental instrument of infectious disease control.
HOCl solutions are already included in the WHO list of coronavirus-effective biocides, and in the US EPA ‘N’ list of disinfecting agents able to control emerging pathogens like SARS-CoV-2. More than 10 branded aqueous HOCl formulations have been cleared by the US FDA for topical use in wound management over the last decade. A Class III medical product approval for HOCl has been granted in the EU, and the Japanese Ministry of Health has approved use of HOCl for topical medical applications. The US FDA has approved HOCl for high level disinfection and sterilisation of medical instruments, including those for use at critical (i.e., sterile) sites. In conclusion, Mr Gee-Turner says: “The COVID-19 pandemic has dramatically increased the use of HOCl in a wide variety of
applications and helped to raise the profile of this promising disinfectant. Infection control measures should maximise effectivity whilst minimising risks to cleaning staff and to the environment, therefore evidence is increasingly indicating that HOCl formulations with proven performance and a long shelf-life represent an excellent choice for cost-effective disinfection.”
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