Tag: pathogens

Part 2 of the Choosing the Right Disinfectant Series

By John Michael Weir | Environmental Services Professional

In the first post in this series, I laid out four variables that drive smart disinfectant selection: microbial targets, contact time, chemistry, and EPA registration. Each one deserves a deeper look. This post focuses on the first and most foundational: knowing exactly which organisms you are targeting and why that determines which disinfectant belongs in your team’s hands.

This is not an abstract exercise. The wrong product applied to the right surface is still the wrong choice. In healthcare environmental services, organism-specific disinfectant selection is a patient safety decision.

Why the Organism Determines the Product

Disinfectants do not kill all organisms equally. The structure of a pathogen determines how vulnerable it is to a given chemical agent. Bacteria with protective spore coats, fungi with thick cell walls, and non-enveloped viruses with protein capsids are all significantly harder to inactivate than vegetative bacteria or enveloped viruses. A product that delivers a 99.9% kill rate against MRSA may have zero efficacy against C. diff spores.

The hierarchy of microbial resistance, from easiest to hardest to kill, generally follows this order: enveloped viruses, vegetative bacteria, fungi, non-enveloped viruses, mycobacteria, and bacterial spores. Understanding where your target pathogen falls in that hierarchy directly informs the level of disinfection required and the chemistry needed to achieve it.

The Spaulding Classification and Environmental Surfaces

The Spaulding Classification system, established by Earle Spaulding in 1968 and still endorsed by the CDC and APIC, categorizes patient care items into three tiers based on infection risk. Critical items contact sterile tissue and require sterilization. Semi-critical items contact mucous membranes and require high-level disinfection. Non-critical items contact only intact skin and require intermediate- to low-level disinfection.

Environmental surfaces fall into the non-critical category. But that designation does not mean any product will do. Non-critical surfaces in healthcare settings still carry significant pathogen burden and serve as a documented transmission route for healthcare-associated infections (HAIs). The CDC estimates that on any given day, approximately 1 in 31 hospital patients has at least one HAI. Environmental surface contamination is a contributing factor that EVS teams directly control.

The practical takeaway for EVS leaders: intermediate-level disinfection is the floor for most clinical areas, and organism-specific threats in your facility may require you to go higher.

Clostridioides difficile (C. diff)

Why it demands special attention

C. diff is a spore-forming bacterium and one of the most common causes of healthcare-associated diarrhea and colitis. According to the CDC, C. diff infects nearly 500,000 Americans annually and contributes to approximately 15,000 to 30,000 deaths. The spores it produces are uniquely hardy: they can survive on environmental surfaces for months, resist heat, and are unaffected by alcohol-based hand rubs and most standard disinfectants.

What the science says about disinfectant choice

The only EPA-registered disinfectants effective against C. diff spores are sporicidal agents, primarily sodium hypochlorite (bleach) at concentrations of 1,000 to 5,000 ppm, and a small number of other sporicidal chemistries. Quaternary ammonium compounds, the most widely used disinfectant class in healthcare, have no sporicidal activity and should not be used as the primary disinfectant in C. diff isolation rooms or during outbreak response.

EPA List K identifies disinfectants registered for use against C. diff spores. Verify that any product used in C. diff precaution environments carries this registration. During active C. diff cases, your facility’s infection prevention team should define the disinfectant protocol, concentration, and frequency. EVS’s role is to execute that protocol with precision and consistency.

Candida auris

An emerging threat with real environmental implications

Candida auris is a multidrug-resistant fungus first identified in 2009 and now present across multiple continents. The CDC has designated it a serious global health threat. What makes C. auris particularly relevant for EVS teams is its documented persistence on surfaces: research has detected C. auris on bedrails, windowsills, IV poles, and medical equipment days to weeks after a patient has left the room.

Disinfectant selection considerations

Not all disinfectants are effective against C. auris, and this is a critical point. Quaternary ammonium compounds, again, may not provide adequate efficacy. EPA List P identifies products with registered efficacy against C. auris. Accelerated hydrogen peroxide and sodium hypochlorite at appropriate concentrations are among the chemistries with demonstrated activity against this organism.

If your facility has had a confirmed C. auris case, your infection prevention team should be driving the disinfectant protocol. If you have not yet had a case, knowing which products on your current formulary hold EPA List P registration is a preparedness step worth taking now.

MRSA, VRE, and CRE

The resistant bacteria most EVS teams encounter regularly

Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and carbapenem-resistant Enterobacteriaceae (CRE) are among the most common multidrug-resistant organisms (MDROs) found in hospital environments. Unlike C. diff, these are vegetative bacteria without spore-forming capability, which means they are more susceptible to a broader range of disinfectant chemistries.

Intermediate-level disinfectants with documented efficacy against these organisms, applied at the correct contact time, are generally adequate for terminal cleaning and daily disinfection of contact precaution rooms. The key variables are not the chemistry but the application: adequate surface coverage, correct product dilution, and adherence to contact time.

Where EVS teams can improve outcomes

Research consistently shows that high-touch surfaces in MDRO isolation rooms are frequently missed or inadequately disinfected. Studies using fluorescent markers and ATP bioluminescence have demonstrated that bed rails, call buttons, light switches, toilet handles, and door handles are among the most missed surfaces during terminal cleaning. Product efficacy is irrelevant if the product is not reaching the surface. Training, monitoring, and accountability systems are as important as the disinfectant itself.

Norovirus and SARS-CoV-2

Non-enveloped versus enveloped viruses

Understanding viral structure matters for disinfectant selection. Enveloped viruses, including SARS-CoV-2, influenza, and RSV, have a lipid outer membrane that is relatively easy to disrupt. Most intermediate-level disinfectants, including quats, AHP, and bleach, are effective against enveloped viruses at standard concentrations and contact times.

Norovirus is a non-enveloped virus, which makes it significantly more resistant to disinfection. It is also highly contagious, with as few as 18 viral particles sufficient to cause infection in a susceptible host. In healthcare settings, norovirus outbreaks can move quickly through a unit if environmental disinfection is inadequate.

EPA List guidance

For norovirus, look for EPA List Q registration, which identifies products effective against norovirus surrogates. For SARS-CoV-2 and other emerging viral pathogens, EPA List N is the reference. Many current healthcare disinfectants carry List N registration, but List Q is a more selective list. Verify both before assuming your current product covers viral threats across the board.

Putting It Into Practice: A Framework for EVS Leaders

The organisms above are not hypothetical. They are present in hospitals every day. An EVS leader’s job is to ensure that the disinfectant being applied to a surface is capable of addressing the organism that surface may be harboring. That requires four things:

  • Know the organisms: Work with your infection preventionist to understand which pathogens are active in your facility and which areas carry the highest risk.
  • Know your product’s registration: Pull the EPA registration for every disinfectant in your formulary. Match it to the EPA lists relevant to your facility’s pathogen profile.
  • Align product to environment: Do not use the same product everywhere by default. C. diff rooms, C. auris cases, and standard MDRO precaution rooms may each call for a different product or protocol.
  • Train to the organism: When staff understand why a specific product is required in a specific room, compliance improves. Context drives behavior.

What Comes Next

The next post in this series focuses on wet contact time: what it means, why compliance is so poor in most facilities, and what EVS leaders can do to close that gap. It is one of the most actionable areas in the entire disinfection process, and one of the most overlooked.

John Michael Weir has 28 years of experience in hospital environmental services, having served in frontline, supervisor, manager, director, and multi-site director roles. He writes at www.johnmichaelweir.com.

dialysis center cleaning

The process of physical cleaning of environmental surfaces using detergent (soap), water, and friction is the critical step required prior to surface disinfection. The combination of the cleaning and disinfection processes is designed to remove and kill vegetative microorganisms on surfaces. Disinfection will not be effective in the presence of dirt, blood, or other bio burden. The  goal of the cleaning step is to remove bio burden and with it, the majority of pathogens. Disinfection is designed to be a synergistic and somewhat redundant step to ensure comprehensive removal/kill of pathogens on surfaces.

The CDC’s Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008, states that, “noncritical surfaces (e.g., dialysis bed or chair, countertops, external surfaces of dialysis machines) should be disinfected with an EPA-registered disinfectant unless the item is visibly contaminated with blood. In that case, an EPA registered tuberculocidal agent with specific label claims for HBV and HIV should be used.”1 the commonly used disinfectant for blood contaminated environmental surfaces is a 1:100 dilution of bleach (500–600 parts per million [ppm] free chlorine).

The environmental surfaces in HD settings at highest risk of transmitting germs are described using different terms. From the perspective of the patient, the term “patient zone” is used to refer to the surfaces which the patient can touch, or can touch the patient, including the chair, armrests, bedside table top/counter, and drawer/cupboard handles. From the HCW or dialysis staff perspective, the term “high touch surfaces” is used to describe surfaces which are frequently touched by HCWs. These include the same surfaces in the patient zone in addition to others such as the exterior surfaces of the HD machine, computer screens, and keyboards. Cleaning and disinfection of these surfaces (patient zone/high touch surfaces) should be performed between all patient treatments, no matter what the patient diagnosis is, in order to prevent spread of environmentally transmitted pathogens including MDROs (e.g., MRSA, VRE, C. difficile) and bloodborne pathogens (e.g., HBV, HCV). Of note, microorganisms can live for varying periods of time in the environment. MRSA has been documented as viable at 38 weeks on external sterile packaging and VRE at 6 months on a wheelchair. HBV can survive for 7 days in dried blood.

There are certain products and principles which are recommended in order to optimize environmental cleaning in healthcare settings, including HD facilities. These include the following tasks which are typically performed by the dialysis nurse or technician.

• Store cleaner/disinfectant separately from skin antiseptics/patient supplies (separate shelves and below patient supplies to avoid potential contamination).

• Perform hand hygiene before and after cleaning the patient station.

• Don gloves when using cleaner/disinfectants.

• Use one set of cleaning cloths or disposable germicidal wipes for each patient station.

• Use microfiber cloths and mops if possible (more effective cleaning products than regular cotton cleaning cloths).

• Clean all frequently touched or “high touch” surfaces in the “patient zone” between patient treatments (chair, armrests, counters, drawer/cupboard handles, exterior surface of the HD machine)—please note that some of these high touch surfaces may be right outside the patient zone (e.g., computer stations), and must also be cleaned between patient treatments.

• Clean the top of an object first and work down to avoid soiling surfaces just cleaned.

• If using cleaning cloths instead of disposable germicidal wipes:

• When using a disinfectant cleaner, wet the surface, use friction to clean, and allow to air dry.

• Fold the cleaning cloth in a series of squares to provide a number of potential cleaning surfaces. A wadded cloth does not clean efficiently.

• Replace cloth as needed. More than one cloth may be required for a patient station.

• Never use the same cleaning cloth for more than one patient unit.

• Never re-dip used cloth into clean disinfectant solution.

Additional cleaning functions, typically performed by housekeeping staff in HD facilities, should include:

• At the end of the day:

• Wet mop the floor

• Clean patient/staff bathrooms and restock paper products/hand hygiene supplies

• Check and refill all hand hygiene product dispensers in nursing stations and at patient stations (soap, paper towels, lotion, alcohol-based hand sanitizer)

• On a routine basis, walls and high dusting should be performed.

Multi Drug Resistant Organisms Cleaning and Disinfection

Many healthcare workers believe the environment of patients with MDROs require special cleaning. Healthcare workers in HD facilities should clean the environment of the MDRO patient as they would for any patient, as many more patients than are known are colonized/infected with an MDRO. Cleaning involves the use of friction on environmental surfaces to physically remove the soil and germs. The wet contact time of the germicide on the surface helps kill or inactivate any remaining microorganisms. The exception is C. difficile, which requires removal by friction and is not inactivated by any surface disinfectant except bleach.