Disinfection of surfaces is a key element in any infection control program, get it wrong and the results can quite literally be deadly for your patients. 1 Healthcare establishments spend significant sums of money every year on cleaning and disinfection, yet often do not attain the required results. 2,3 This paper will look at some of the frequently overlooked aspects of cleaning and disinfection programs used in healthcare settings, and how those gaps can be closed. Cleaning and disinfection are not the same thing, however, without adequate cleaning, disinfection cannot be reasonably accomplished. To both clean and disinfect requires a well-managed program and clearly defined responsibilities.4

The Basics

To clean and disinfect surfaces, you need an integrated program that includes disinfectants, wipes, mops, trained personnel, monitoring, and an assortment of additional components. More importantly, all of these components need to work together to firstly collect and remove soil (dirt) then disinfect all the required surfaces on a consistent basis. Ask some basic questions, is my disinfectant compatible with the wipe used to apply the disinfectant, or will it bind to the cloth? Has the staff applying the product been properly trained in the required method of application? Will any of the chemicals selected have a negative impact on the surfaces to which they are applied? There are many products on the market, selecting the correct ones in an integrated program where each component is compatible then training your people on how to correctly apply the products are the keys to reducing infection rates and providing a safer environment for both patients and staff.


Does Your Disinfectant Kill Everything?

Health Canada and the Environmental Protection Agency (EPA) register disinfectants based on their ability to kill specific pathogens. 5 The registration is based on laboratory-generated data indicating to a high degree of certainty that when applied at the specified concentration and contact time, the disinfectant will kill the specified pathogen. Not all the things a product kills can possibly be listed on the label, but as a general guide, look for types of organisms and apply the Spaulding scale. 6 A good disinfectant should kill both gram-negative and gram-positive bacteria, large enveloped and small unenveloped viruses, plus fungi – both filamentous and yeasts. It is better, of course, if the disinfectant is also effective against mycobacteria and endospore-forming bacteria. Spauling places organisms in a hierarchy of easy to more difficult to kill though there are some quirks in the rankings depending on chemistry; alcohol, though less effective against small unenveloped viruses such as norovirus, is more effective than most things against mycobacteria, hydrogen peroxide is very effective against bacteria, however, heavy catalase producers do appear to have some inherent protection from peroxides.

   Most commercial disinfectants meet the requirements for a hospital-grade product (i.e., kill both gram-negative and gram-positive bacteria) and meets the blood-borne pathogen standard (i.e., kill HIV and HBV), and have a basic fungal claim typically based on trichophyton interdigitale. The better ones also include small unenveloped viruses (i.e., norovirus or a surrogate) and mycobacteria (i.e., mycobacterium bovis or surrogate) the best disinfectants also cover endospore-forming bacteria (i.e., Clostridioides difficile). The ability to kill endospore-forming bacteria is typically regarded as a sufficient indication that a product is effective against other challenging organisms such as Candida auris.7 Our recent experiences with the SARS-CoV-2 pandemic have also shed light on the use of the Spaulding process in the emerging viral pathogens claim espoused by the EPA,8 where with a product shown to be effective against more difficult-to-kill viruses we can assume it kills newly emerging viruses.

    A significant portion of the population is known to be asymptomatic carriers of C. difficile who are likely to shed into any room they occupy, therefore increasing the risk of infection for subsequent occupants. Because of this, many hospitals chose to disinfect all rooms with sporicidal products regardless of the patient status. One must also consider the impact of pathogens migrating from isolation rooms, in the work published by Donskey on the impact of pathogens on floors. It is clear that pathogens in a patient room will migrate not just to other surfaces in the patient room, but to other surfaces in the same unit.9 It is therefore vital to ensure that all pathogens are addressed in a cleaning program.

   The primary argument against the use of disinfectants effective against endospore-forming bacteria on a daily basis is that these tend to be more aggressive chemistries – either bleach based or peroxyacetic-acid-based. The concern is the level of damage those products cause to the building fabrics and medical equipment in addition to the elevated health risks to employees from these products. The recent introduction of NaDCC-based products has presented an alternative option allowing for a  C. difficile product that does not have many of the disadvantages of typical sporicidal products.



In the real world, unlike the standard tests used to register disinfectants, bacteria grow and survive in biofilms, including on normally dry surfaces. 10  The biofilms are a complex matrix, which can include bacteria, viruses and fungi. Within that matrix, these microorganisms are protected from the impact of chemical disinfectants and UV light.11 Within the biofilm matrix, bacteria can swap plasmids, including those that code for antibiotic resistance, increasing the risk of infection from MDROs. What is in biofilm does not stay there, with studies showing both gloved and ungloved hands can pick up bacteria from biofilm even through a sheet.12

Disinfectants that are not effective against bacteria in biofilms, cannot truly protect patient populations. 13 Check the label and ask your supplier to demonstrate their product efficacy against biofilm-bound bacteria and viruses. It should be noted that a recent paper showed that as with other viruses, SARS-CoV-2 can both populate and survive within biofilm. 14


Dilution and Preparation

 It is possible to purchase ready-to-use disinfectants, these come with a significant cost penalty at roughly 10-15 times the cost per gallon of concentrated disinfectants, they also take up to 40 times the volume and weight for shipping, generating 40 times the amount of plastic and cardboard waste. The more cost-effective and more sustainable option is to use concentrates and add water on site. Typically accomplished through the use of auto diluters, unfortunately these are often inaccurate and require both routine maintenance and testing to assure the correct product concentration is delivered. One study showed that only 18% of auto diluters tested produced the correct concentration of disinfectant. 15 An alternative approach is to use disinfectant in the form of a pre-weighed tablet that can simply be dropped into a fixed volume of water producing a known concentration of disinfectant.


Means of Application

Make sure that the means used to apply the product is compatible with the chemistry used and that the method used matches the application instructions. There are reasons that a product label has instructions for use, follow them.  The biggest challenges are with quaternary (quat) ammonium-based products that chemically bind to the fabric of the cloth or mop used to apply the product, 16 resulting in a solution with less than the minimum concentration required to be effective as a disinfectant. There are specially treated disposable wipes on the market that prevent quat binding, but all launderable microfiber is subject to this effect.

   One way to avoid the issues of quat binding is to apply products using a spray method rather than a cloth. This increases the number of steps required in the process and when using a typical trigger spray requires a lot of pulls of the trigger for each room. A better alternative would be the use of an electrostatic sprayer though again the user is cautioned to ensure that the product they are using is

registered for use with an electrostatic sprayer, and that the manufacturer’s instructions for personal protective equipment (PPE) and hold times before reoccupying a room are followed. Some products may require up to 20-minute hold time before a room can be reoccupied after application with an electrostatic spray. Due to the increased health risk associated with the spraying of disinfectants, many institutions do not allow this practice in an occupied room, but it does present an option for terminal cleans.

   Some products require a two-step action – a preclean followed by a disinfectant step, others claim to be single-action cleaning disinfectants.  In either case, all surfaces that are to be disinfected must be visibly clean and free from dirt or debris before the application of disinfectant. There are a pair of areas where a preclean is an absolute requirement. One is any C. difficile isolation room, where a preclean is always required prior to disinfection. The second is the cleaning for bloodborne pathogens or other potentially infectious materials, in this instance, the preclean is meant to remove all visible blood and bodily fluids.

   Precleaning can be performed with the same product that will be used as a disinfectant, it is better if the disinfecting product has some surfactants to assist in removal of the soil. It is important that the cloth used in the pre cleaning process is disposed of then replaced with a fresh cloth to apply the disinfectant. If a separate cleaning product and disinfectant is chosen for this process, it is vital to ensure the cleaning agent and disinfectant are compatible.

   It is important that the cloths used for the cleaning and application  of disinfectants are a high-quality microfiber. Dirt and pathogens should be collected from the surface and held in the fabric, not simply moved from one point to another. Cloths and mops can be either disposable or launderable, whichever is used, it is important that they are compatible with the chemistry used, and that there are sufficient supplies available to allow frequent changes after use.

   Launderable microfiber has a finite life, and if not laundered correctly, loses many of the valuable properties associated with its design before its normal expiration date. A regular process of rotating older used cloths out of circulation and inspecting for damage after each use is required to maintain function. The other challenge when using a contract laundry service is ensuring that the reprocessing is performed correctly and that the cloths delivered back to you are the ones that came from your establishment. Ensuring an adequate supply of cloths for all shifts often requires an excess to cover the laundry and shipping process. We encourage frequent changes of cloths and mops. We never want to see a cloth or mop recharged with disinfectant (double dipped) during a disinfection process. The alternative to reusable cloths is the use of disposable mops and cloths, these can be as effective, though typically more disposable cloths per room are required compared to launderable microfiber. Single-use disposable cloths add to the waste coming from the hospital and in many instances, are not biodegradable. Of course, there are many different blends of materials used and different qualities of fabric used in disposable wipes, how much liquid a cloth takes up then releases requires careful consideration.

One note of caution for those who chose a program of routine disinfection with a quat-based chemical that switches to a bleach-based product for C. difficile rooms, a separate set of wipes will be required for the two chemistries. Quat that has bound to the fabric of the wipe will not be entirely removed in the laundry process. Residual quats on wipes will react with bleach-based products producing a noxious odour.


Are the materials you are using compatible with each other and the surfaces you expect to clean and disinfect? We discussed above the challenge associated with quat binding, but there are also challenges with other cleaning products, quite often there are products in use specifically for floor finishing and cleaning, glass cleaning, tile and grout cleaning, bathroom cleaners, as well specialty products representing a wide range of acids, alkalis, oxidizers and reducing agents. The accidental mixing of incompatible products can have a disastrous impact, with careful thought required over the use and separation of different chemistries.

   As we see the need to increase disinfection of surfaces not previously covered in a typical disinfection program, we also find that many of the commonly used products are simply not compatible with the surfaces they must disinfect. As an example, the disinfection of floors was not previously considered a priority, since the publication of papers showing that floors can be a source of contamination of many surfaces in the patient space,17 indicating that floor disinfection should now be part of the daily clean. Unfortunately, there are few products that are suitable for disinfecting floors. The CDC recommends against alcohol or phenolics, quats are likely to bind to the mop, bleach-based products will destroy most floor finishes, and hydrogen peroxide or PAA-based products will react with calcium carbonate in the VCT if the floor finish is not 100% intact. NaDCC does provide an option, but this must be applied using high-quality microfiber and the application should be done to minimize the quantity of product used to reduce visible residue.


The potential for employee exposure to disinfecting chemicals and the potential health effect both long-term and shortterm are a consideration in any chemical program. Many of the products used on a daily basis, and especially many of the sporicidal products present an immediate health risk to the person applying the disinfectant. While appropriate PPE can help to reduce the health risks from a known hazard, it is better to select a product with less health risks assuming a comparable performance. Look at the HMIS rating of your chosen disinfectant in both the concentrated form and the in-use dilution. The lower those numbers, the lesser the risk associated with the product. Remembering that all disinfectant products are designed to kill bacteria and viruses and hence have an inherent risk, there are products with neutral pH that will do less damage to the skin and the respiratory tract that should be considered over more aggressive acidic or caustic products.


Protocol or Product

While it is vital to provide the right tools for the people tasked with performing cleaning and disinfection, it is as important to note that those individuals must be provided with the appropriate training and time to perform their critical work. Not the least part of the training is how to clean and the sequence or order of cleaning, as well as the correct application of the products in use. The training should include the basics: top to bottom, outside to inside, clean to dirty, changing cloths often, changing gloves as needed, wiping in a straight line, using a figure-eight motion to clean the floor, applying sufficient disinfectant to attain the required contact time, but not too much to over saturate. This must all be taught and monitored, including a clear demarcation as to who cleans what.

This is not a quick operation and requires that people are given training time, then time to actually accomplish the required tasks. This probably means not judging our efficiency on how fast  a room is turned over, but more on  how few infections are transmitted.  If we are going to invest that much time to train personnel, we should probably also invest in retaining them. Perhaps the least popular opinion is that rather than housekeepers, we refer to staff as infection control technicians and pay them accordingly. Employing sufficient personnel, training them and paying them is likely to cost more than all the improved tools we provide.

One of the benefits to consider when looking at a disinfectant is how few products one can use in a facility, if a general disinfectant is first used, and then switched to a different product for specific pathogens such as C. difficile or Candida auris. This would double the training requirements and increase the chances for errors. Perhaps one more reason to standardize with one disinfecting product to cover general and specific disinfection is that well founded and well-thought-out programs which minimize the potential for error or cross-contamination with well trained personnel will always net better results.


What Can Go Wrong?

Perhaps the single biggest failure in a cleaning program are those things that simply get missed, often that is a failing in training or expectation. Multiple studies have shown that it

is common for up to 60% of surfaces that are scheduled to be cleaned and disinfected to be missed during either daily or terminal cleaning. 17, 18 Even when extensive training and monitoring is applied, it is often challenging to get much above 80% compliance. 18

One of the major driving forces for surfaces not being properly cleaned is a simple time constraint though one also hears concerns over not wishing to disturb a patient, not wanting to disturb medical equipment, and basic issues regarding not having clearly defined responsibilities for things such as head wall fixtures.

   A common solution to the issue of missed surfaces is the introduction of no-touch disinfection systems such as portable UV lights. These systems do have some ability to deactivate organisms though probably not to the level claimed by some manufacturers; remember these units are not regulated under the Federal Insecticide, Fungicide, and Rodenticide Act and their efficacy claims are not registered by the EPA. The single biggest obstacle to their use is that like electrostatic sprayers, they may only be used in unoccupied spaces. No-touch systems can supplement the disinfection of a room during a terminal cleaning, though it cannot replace the physical removal and disinfection process. The other consideration when looking at UV systems is the operating costs, not just the initial capital costs. To be truly effective, portable UV systems need dedicated personnel to operate them, people who can get them to the correct room at the correct time, set up the lamps and the rooms correctly, too many facilities that purchase units do not budget for the extra staff needed to get the most from the system.

   In addition to the potential for missed surfaces, many of the points outlined above regarding binding and wipes can apply, however, the biggest failure is often contact time. Does the surface remain wet for a sufficient period of time to allow the disinfectant to do its work? Many commonly used disinfectants require contact times of up to 10 minutes in order to attain the required disinfection. Certifying organizations will monitor the time taken for a disinfectant to dry. If the contact time is not attained, the action will be recorded as a one of non-compliance. The simplest solution is to select a product with an attainable contact time, and preferably one that attains the desired result in less than five minutes, but ideally in less than four.


Monitoring and Efficacy

For a management team, the ability to train to a protocol must be supplemented by regular monitoring and re-education. One thing that is apparent is that without constant correction, programs have a habit or wandering off course. One of the most basic aspects is the ability to assess performance and basic compliance.

   There are many tools available to the management team to ensure that the process is being followed correctly, and that all the surfaces specified for cleaning and disinfection are treated. Everything from basic visual inspection, use of invisible markers, ATP swabs, and of course culture tests of surfaces can all help to determine if a room has been properly cleaned. One of the newer options is the multi-channel UVA lamp which shows the presence of dust, bacterial colonies and biofilm on a surface that may have been missed during the cleaning process. This provides immediate opportunities for staff education. It is important that monitoring is done for teaching purposes rather than as a scolding. Monitoring of routine work activity by a supervisor or manager requires a significant level of time and commitment, which will translate into additional costs.


From the above, the hope is that practitioners realize that a professionally predicated and managed cleaning and disinfection program can help reduce infection rates, this requires adequate resources and commitment. A short list of the requirements can be summed up as:

  • Clearly defined protocols and responsibilities;
  • Well-trained personnel provided with the correct tools in an integrated program of compatible products;
  • A disinfectant that covers all the required pathogens in a reasonable contact time and includes biofilm and endospore-forming bacteria;
  • A disinfectant that is safe to use and will not damage surfaces;
  • Wipers and mops that collect dirt and pathogens; and,

A monitoring program that allows rapid assessment of the surfaces in the room and immediate instruction on corrective actions. As stated earlier, perhaps thinking about the cleaning and disinfection process being performed by infection prevention technicians may give a better perspective



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