Quaternary Ammonium Disinfectants: Lost in Translation?

Author: Joan Hebden, RN, MS, CIC, FAPIC, FSHEA

There has been a plethora of scientific literature demonstrating that healthcare-associated pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE) and Clostridium difficile, frequently contaminate both porous and non-porous surfaces in the healthcare environment. This microbial burden on environmental surfaces serves as a reservoir for direct transmission of pathogens to the patient or as an indirect mode of transmission through contaminated reusable patient care equipment and/or healthcare workers’ hands and gloves. Along with hand hygiene and the implementation of best practices to prevent healthcare-associated infections (HAIs) and multi-drug resistant organisms (MDROs), environmental cleaning is a fundamental component of a comprehensive infection prevention program.

The infection prevention (IP) and environmental services (EVS) leadership of healthcare facilities are responsible for choosing the disinfectant to be used, defining the cleaning processes, which includes appropriate use of the disinfectant, and monitoring adherence to these processes. Quaternary ammonium-based (Quat) products, including Quat/alcohol solutions, and sodium hypochlorite (bleach) are the most chosen products for standard cleaning. More recently, the choice has become more challenging with the introduction of new disinfectants (e.g. improved hydrogen peroxide, peracetic acid/hydrogen peroxide) and disinfection technologies (e.g. “no-touch” mobile devices that emit continuous ultraviolet light UV-C) accompanied by technical briefs and scientific papers that may not be well understood or lack critical information. Additionally, as traditional manual cleaning methods are often suboptimal, these leaders are seeking interventional strategies that enhance cleaning, promote standardization, have demonstrated improved patient outcomes and are cost-effective.

Han and colleagues¹ reviewed 4 systematic reviews and 76 primary studies of environmental cleaning and found that most studies do not report the thoroughness of cleaning or adherence to the manufacturers’ recommendations for proper use of their products. They concluded that products need testing in clinical settings and that different cleaning methods need to be studied for comparative effectiveness.

Is a Quat still OK to use?

Rutala and Weber² have identified the properties of an ideal disinfectant and recommend using these five key criteria:

1. Broad spectrum – does the product kill the most prevalent healthcare pathogens?
2. Kill times and treatment times – how quickly does the product kill the pathogens and does the product keep surfaces treated* for the kill times listed on the label?
3. Safety – toxicity rating acceptable? what level of personal protective equipment is required? compatible with common surfaces in your facility?
4. Ease of use – does the product clean and disinfect in one-step? is the product odor acceptable? does the product work in the presence of organic matter? does the product come in convenient forms to meet your facility needs (e.g. liquids, sprays, wipes)?
5. Other factors – does the company offer training? can the product help standardize disinfectants in your facility? is the overall cost of the product acceptable?

Quats are bactericidal, fungicidal and virucidal against enveloped viruses (e.g. HIV), in general, are not tuberculocidal or virucidal against non-enveloped viruses (e.g. norovirus), and are not sporicidal. However, Quat/alcohol formulations have demonstrated activity against norovirus surrogate viruses³. Sani-Prime™ Germicidal Spray from PDI is currently available. Sani-Prime is powered by ACCELOQUAT™ formulation ( <1% didecyl dimethyl ammonium chloride, 25-35% ethyl alcohol and 20-30% isopropanol) and is a 1 minute bactericidal, virucidal, fungicidal, and tuberculocidal.

Quats are good cleaning agents, have persistent antimicrobial activity when undisturbed⁴, are surface compatible and inexpensive. A disadvantage that has been cited pertains to cotton material binding, which lessens the microbiocidal activity of the Quat; however, the majority of EVS staff currently use microfiber cloths for cleaning or pre-moistened non-woven wipes. Additionally, due to the lack of sporicidal activity of Quats, an alternative disinfectant – generally bleach – is recommended for cleaning of C. difficile patient rooms.

In the recently published Benefits of Enhanced Terminal Room (BETR) Disinfection study⁵, Anderson and colleagues provide IP and EVS leaders with strong evidence of the efficacy of enhanced disinfection (UV light) and confirm that the contaminated hospital environment is a modifiable risk factor. The BETR disinfection study was a multicenter, cluster-randomized, crossover study done in nine US hospitals with four strategies for terminal room disinfection (disinfection of a room between occupying patients) and an evaluation of the impact on acquisition and infection due to the target organisms -MRSA, VRE, multi-drug resistant Acinetobacter, and C. difficile The strategies included traditional disinfection with quaternary ammonium, except for C. difficile rooms in which bleach was used, along with three enhanced strategies: bleach alone, quaternary ammonium with disinfecting UV device (except C. difficile rooms in which bleach and UV device was used) and bleach with UV device. The authors found that adding a UV-C device to quaternary ammonium disinfection decreased the risk of subsequent acquisition and infection by target organisms by 30% (p=0.036).

It is essential that IP and EVS leaders use the available science when choosing the ideal disinfectant for their facility. The “accelerated” Quats with alcohol are rapid-acting, have broad and persistent antimicrobial activity and low toxicity. In conjunction with UV-C technology, Quats significantly decreased the acquisition of epidemiologically significant MDROs.