Industry Roundtable: Sporicides, Quaternary Ammonium Compounds and Advanced Hydrogen Peroxide

For this industry roundtable, ICT invited manufacturers to provide information on sporicides, quaternary ammonium and advanced hydrogen peroxide, to assist infection preventionists, environmental services personnel and purchasing managers in making product-evaluation decisions.


ICT: What are the benefits of sporicides over other chemicals for surface disinfection in healthcare facilities?

Spore-forming bacteria, such as Clostridium difficile (C. difficile), are among the most difficult microorganisms to eliminate from healthcare surfaces due to their resiliency. Sodium hypochlorite, the active ingredient in bleach, is one of the few actives that is effective at killing C. difficile spores on environmental surfaces and it is cited by more clinical studies to kill C. difficile than any other active ingredient. In addition to their sporicidal activity, sodium hypochlorite surface disinfectants designated for use in healthcare settings are often Environmental Protection Agency (EPA)-registered to kill a wide range of pathogens including bacteria, enveloped and non-enveloped viruses, and fungi. In fact, bleach is the most studied and proven disinfectants available today. Bleach also meets the Centers for Disease Control and Prevention (CDC) criteria for use against emerging pathogens.
- Sarah C. Bell-West, PhD, senior scientist in research and development with Clorox Healthcare

ICT: What are some examples of the superior efficacy of sporicides?

Bleach and other sporicides have proven effective in helping facilities reduce Clostridium difficile infection (CDI) rates and other healthcare-associated infection (HAI) rates. In an era in which healthcare is delivered in a variety of settings and patients often move between facilities, numerous reports have demonstrated the epidemiology of HAIs is shifting. For example, a recent CDC-funded study estimated that 65.8 percent of CDI cases in the United States were healthcare-associated while only 24.2 percent of CDI cases were hospital-onset.
Since many HAI-causing pathogens, like C. difficile, are easily transferred via contaminated healthcare worker hands and environmental surfaces, healthcare professionals are becoming more proactive in their environmental infection control efforts, looking at ways to prevent cross-contamination, and even expanding sporicidal disinfectant application to areas beyond isolation rooms. For example, as part of a multi-modal infection prevention strategy, a daily and terminal cleaning regimen of all patient rooms using Clorox Healthcare® Bleach Germicidal Wipes resulted in an 85 percent decrease in hospital-acquired C. difficile infection rates over a 12-month period. The researchers commented that the study design included several unique aspects that in their opinion contributed to its success, one of which was the fact that all rooms were cleaned daily with bleach wipes, regardless of whether the occupant had a documented C. difficile infection.
Another study from a tertiary care hospital in Providence, R.I., showed a 70 percent decrease in the incidence of healthcare-associated C. difficile infection rates and a 63 percent decrease in yearly mortality in patients with healthcare-associated C. difficile infections after implementing a hospital-wide infection control bundle that included enhanced cleaning of patient rooms and equipment using sodium hypochlorite-based cleaning agents.
- Sarah C. Bell-West, PhD, senior scientist in research and development with Clorox Healthcare

ICT: What are some best practices for handling and using sporicides?

Before using any disinfectant product, healthcare professionals should take time to review product labels as well as safety data sheets (SDSs) to familiarize themselves with the product chemistry, directions for use, and safety information. It’s also important to use the proper personal protective equipment (PPE), when appropriate, to ensure safe handling.
The use of ready-to-use bleach sporicidal disinfectants, such as Clorox Healthcare® Bleach Germicidal Cleaner and Clorox Healthcare® Bleach Germicidal Wipes, can also improve overall efficiency when compared with the use of concentrated sporicidal disinfectant solutions that require proper dilution and should be prepared on a daily basis, a process which recent evidence has shown to be very time consuming. In a 2015 study published in the American Journal of Industrial Medicine where researchers monitored healthcare worker cleaning and disinfecting tasks in five hospitals over a two-year period, the authors found that hospital nursing and environmental services staff spent an average of 8 to 15 minutes per shift mixing chemical products.
Another important consideration for handling and using sporicides is cross-contamination, or the spread of pathogens from contaminated to clean surfaces. Cross-contamination can be influenced by two factors: product and protocol. Selection of the right disinfectant product for the right job must be combined with enhanced staff education and standardized cleaning and disinfection protocols to ensure disinfectant products are being properly used to reduce transmission of pathogens in the healthcare environment.
Research has also demonstrated that non-sporicidal wipes and overused sporicidal disinfectant wipes can easily transfer C. difficile spores from contaminated to clean surfaces.
- Sarah C. Bell-West, PhD, senior scientist in research and development with Clorox Healthcare

ICT: What should healthcare professionals know about contact/dwell times and the use of sporicides?

When using EPA-registered disinfectants in healthcare settings, it is crucial that end users comply with manufacturer’s directions for use. EPA-registered surface disinfectant labels might also contain special instructions for use for particular organisms, such as C. difficile, or for use in special situations (i.e. surfaces contaminated with blood or body fluids), including any pre-cleaning steps, so it is important to read the entire product label prior to use.
Following contact times listed on product labels is also very important. Allowing the disinfectant solution to remain wet on surfaces for the appropriate contact time ensures the microorganisms present on the surface are exposed to the disinfectant long enough to be effective against them. Contact times are not always the same for every organism, so again it is important to read the entire label.
Choosing the proper cleaning and disinfecting solutions and ensuring they are used compliantly are crucial steps toward ensuring a safe environment of care, but it is also important to protect environmental surfaces and medical devices – critical investments for healthcare facilities – which is why healthcare professionals need to work to identify products that are compatible with their equipment.
To help with these issues, Clorox Healthcare launched Clorox Healthcare Compatible™ to help equipment manufacturers meet FDA guidelines for the validation of cleaning and disinfection of medical devices. With Clorox Healthcare Compatible™, Clorox Healthcare works with manufacturers to validate compatibility claims via third-party testing and identifies which disinfectant products are safe for use on everything from lights and beds to infusion pumps and ultrasound transducers. Equipment manufacturers also endorse the use of approved Clorox Healthcare disinfectants in their user guides for easy reference.
- Sarah C. Bell-West, PhD, senior scientist in research and development with Clorox Healthcare


ICT: What are the benefits of quats over other chemicals for surface disinfection in healthcare facilities?

Quaternary ammonium compounds (quats) are widely used in the healthcare environment for disinfection of non-critical environmental surfaces, including floors and walls. Quats tend to be relatively broad spectrum, and demonstrate good cleaning ability while being compatible with a variety of surfaces. Most quats are effective against Gramnegative and Gram-positive bacteria, and enveloped viruses. They are less likely to be effective against non-enveloped viruses, such as norovirus, and are rarely effective against TB unless the quat active is enhanced with additional actives or solvents. Quats do not demonstrate sporicidal activity.  
Traditional quats are generally effective against the organisms mentioned above with a contact time of 10 minutes, but newer formulations can have a contact times as low as 3 minutes. Because they are not tuberculocidal, quats are generally classified as low-level disinfectants, as opposed to intermediate-level disinfectants. In use format, they are effective in that they have the following qualities: 
Broad spectrum: Kills a wide range of pathogens
Safe: In concentrated form, quats can be corrosive and present risk to users; however, once properly diluted, they present a significantly lower risk to users
Compatible: Quats are compatible with most assets in a facility. They tend to leave a residual which may need to be rinsed from time to time.
Fast acting: Newer quats are now available with dwell times as low as 3 minutes to kill many common healthcare associated pathogens
Low cost: At dilution, quats tend to be one of the lower cost disinfectant technologies, and are effective for use from floor to ceiling
Stable: Use solutions can be stable for weeks or even months
- Jim Gauthier, senior clinical advisor, infection prevention, Diversey Care

In the past three decades or so, systematic and convincing evidence-based studies have been obtained to show that surface disinfection plays an important role in the chain of infection. For example, hand hygiene effects can be significantly compromised if surface disinfection is not conducted properly.1-2 When we try to prevent infections, understanding the transmission pathways or portals of entry is very important. Even though inanimate surfaces usually are not immediately related to direct transmission such as the fecal-oral route, studies have shown that the indirect transmission contributed by inanimate surfaces not only can transmit pathogens into direct paths, but also the environmentally-medicated transmission can last much longer than the direct transmission due to the long survival period of many pathogens on environmental surfaces.3-4 
There are roughly two main kinds of surface disinfectants available on market. The first kind is oxidant based such as bleach, peracetic acid or hydrogen peroxide. The second kind is quaternary ammonium-based. The latter kind can be further divided into: high-alcohol, low-alcohol and no-alcohol formulas. The benefits of quats generally are: 1. Better material compatibility; 2. Better cleaning ability. Cleaning is a prerequisite of disinfection. 3. Better aesthetics (less residues). This explains why the quat-based disinfectants are the most widely used in healthcare facilities.

1. Kundrapu S, Sunkesula V, Jury LA, Sitzlar BM, Donskey CJ. Daily Disinfection of High-Touch Surfaces in Isolation Rooms to Reduce Contamination of Healthcare Workers’ Hands. Infect Control Hosp Epidemiol 2012;33:1039-42.
2. Repp KK, Hostetler TP, Keene WE. A Norovirus Outbreak Related to Contaminated Surfaces. J Infect Dis 2013;208:295-8.
3. Lopman B, Gastanaduy P, Park GW, Hall AJ, Parashar UD, Vinje J. Environmental transmission of norovirus gastroenteritis. Curr Opin Virol 2012;2:96-102.
4. Kramer A, Schwebke I, Kampf G. How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infect Dis 2006;6.
- Yatao Liu, PhD, director of worldwide clinical affairs and business development, Metrex 

Quaternary ammonium chloride (QAC) compounds are the most common active ingredient found in disinfectants used in healthcare environments and have been used safely and effectively for many years. This is largely because products formulated with QACs are readily available and versatile in their use. In addition, they typically offer broad-spectrum efficacy (Gram-positive and Gram-negative bacteria, pathogenic fungi, bloodborne pathogens, and Mycobacterium) and do not have the unpleasant odor of oxidizing-based products, such as sodium hypochlorite (bleach) and accelerated hydrogen peroxide. QACs offer advantages versus other disinfectant chemistries due to their superior stability, enhanced material compatibility, broad spectrum mitigation ability, and improved safety and toxicity.
QACs are also good cleaning agents and are widely used as disinfectants for noncritical environmental surfaces and devices used in healthcare settings. The broad-spectrum efficacy claims obtained from the QAC alone as well in addition to alcohol allow for a broad-spectrum disinfectant with a fast contact time (less than or equal to 3 minutes) and excellent compatibility.
- Jaime M. Ferreira, PhD, PDI research and development

ICT: What are some examples of the superior efficacy of quats?

Many quat formulas on the market can kill common microorganisms including VRE, MRSA, influenza, adenovirus, Acinetobacter, Klebsiella, and many more vegetative bacteria. Some newer formulas are effective against norovirus with longer dwell times and higher concentrations. Most quats will easily meet the Occupational Safety and Health Administration (OSHA)’s Bloodborne Pathogen Standard, killing HIV and hepatitis B. There are highly concentrated quat formulas providing excellent one-step, cost-effective cleaning, disinfection and odor control.
- Jim Gauthier, senior clinical advisor, infection prevention, Diversey Care

With the technology advancement and more understanding of microorganisms, we are able to develop quat-based synergistic disinfectants in both wipe and liquid forms that can provide the best combination of contact time, broad spectrum pathogen claims, material compatibility and aesthetics, cleaning property and safety. Let us focus on efficacy here. According to the National Healthcare Safety Network (NHSN) annual update published in 2008, among 28,502 reported cases of HAI, a total of 33,848 pathogenic isolates were recovered and 4,400 (13 percent) were fungi.1 In a multistate point-prevalence study conducted in 183 hospitals including 11,282 patients, Candida species alone (one type of fungi) were responsible for 6.3 percent of  HAIs.2 From the data, we can see fungal infections cannot be downplayed. As a comparison, some hydrogen peroxide-based disinfectant products take 8 minutes or even 10 minutes’ contact time to disinfect fungi. Can our healthcare professionals wait for 8 or 10 minutes? Will the surface maintain the wetness during the entire contact time? Some quat-based disinfectants need much shorter contact time to disinfect fungi (3 minutes for CaviWipes™/CaviCide™ and 1 minute for CaviWipes1™/CaviCide1™).
Efficacy can be relatively easily judged by looking at if it is broad spectrum (bactericidal, tuberculocidal, virucidal and fungicidal) and the corresponding contact times. Other superior efficacy such as cleaning ability, material compatibility and aesthetics may hard to be compared just by looking at the technical data. Long-time clinical applications would be good evidence to show the superior performance with the continuously evolving quat formulas.

1. Hidron AI, Edwards JR, Patel J, et al. Antimicrobial-Resistant Pathogens Associated With Healthcare-Associated Infections: Annual Summary of Data Reported to the National Healthcare Safety Network at the Centers for Disease Control and Prevention, 2006-2007. Infect Control Hosp Epidemiol 2008;29:996-1011.
2. Magill SS, Edwards JR, Bamberg W, et al. Multistate Point- Prevalence Survey of Health Care- Associated Infections. N Engl J Med 2014;370:1198-208.
- Yatao Liu, PhD, director of worldwide clinical affairs and business development, Metrex 

The bactericidal action of the QACs have been attributed to the inactivation of energy-producing enzymes, denaturation of essential cell proteins, and disruption of the cell membrane resulting in physical cell death.1  Generalized statements that QACs overall are not effective against target organisms has led to a misrepresentation of the efficacious ability of QACs to mitigate specific target organisms, specifically norovirus.2 QAC-based formulations are tested using the Environmental Protection Agency (EPA) standardized testing protocols for claims against a specific organism. These tests must be conducted with the specific organism or surrogates to ensure efficacy. In numerous studies published, the authors neglected to determine if the product had been registered for that specific organism or application and most of the QACs had been tested alone versus in conjunction with any of its synergistic ingredients.3 In fact, QACs alone have the ability to mitigate 37 of the top 50 organisms as well as persistent organisms such as Acinetobacter spp.(3 days to 5 months), ESCAPE pathogens (15 days), Shigella spp (2 days to 5 months), MRSA (7 days to 7 months), Adenovirus (7 days to 3 months) and Candida Albicans (1-120 days).4  Many of the top QAC surface disinfectants on the market have demonstrated efficacy versus these bacteria, viruses and fungi.

1. Mayhall GC. Hospital Epidemiology and Infection Control, 3rd Ed. Chapter 85: “Selection and Use of Disinfectants in Healthcare”. Lippincott Williams & Wilkins. Philadelphia. 2004. Page 1505.
  2. Jimenez L, Chiang M. Virucidal activity of a quaternary ammonium compound disinfectant against feline calicivirus: a surrogate for norovirus. Am J Infect Control. 2006 Jun;34(5):269-73.
  3. Eterpi M, McDonnell G, Thomas V. 2009. Disinfection efficacy against parvoviruses compared with reference viruses. J Hosp Infect 73:64–70.
  4. Kramer, Axel; Schwebke, Ingeborg; Kamf, Gunter. (2006) How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BioMed Central.
- Jaime M. Ferreira, PhD, PDI research and development

ICT: What are some best practices for handling and using quats?

Having a good dilution control dispensing system will help provide safe and accurate product dosing to ensure optimal performance. Over-dilution or under-dilution can affect the efficacy of the end-use product. Checking the quat at the end-use dilution with test strips recommended by the manufacturer can help ensure that the product is being dispensed properly. It is also important to ensure that cleaning tools are compatible with the disinfectant, as quats are known to bind with some cleaning tools, reducing their efficacy.
- Jim Gauthier, senior clinical advisor, infection prevention, Diversey Care

Always make sure read the labels first to know the appropriate PPE requirement, the contact time and other instructions. Usually at the presence of visible soils, cleaning is required prior to disinfection. The quat itself is a good cleaner, so you can just use the same quat disinfectants (wipe or liquid) to do the cleaning before you use the same product for disinfection. In addition, some quat disinfectants are one-step cleaners and disinfectants such as CaviWipes1™/CaviCide1™ in the absence of visible soils.
Disinfectants are registered by the Environmental Protection Agency (EPA) as “antimicrobial pesticides” and are defined as substances used to control harmful microorganisms on inanimate objects and surfaces. Data on a product’s chemistry, efficacy, toxicity to humans, animals and plants, and other parameters must be tested and submitted to the EPA prior to the marketing of the chemical. Product labels contain important details to assist with infection control efforts. Additionally, it is a violation of federal law to use a product in a manner inconsistent with its labeling. Therefore, strict attention must be given to the proper use. For example, we cannot mix different disinfectants together such as quats with bleach, which will react and create a toxic vapor.
As a company dedicated to infection prevention, in addition to provide the most innovative products to healthcare professionals, we also offer education and in-service programs. Metrex is a big advocate for education and service. We believe the best infection prevention performance is a combination of both products and best practice.

- Yatao Liu, PhD, director of worldwide clinical affairs and business development, Metrex 

Any surface disinfectant product used in the U.S. must be registered with the Environmental Protection Agency (EPA), therefore demonstrating efficacy versus targeted organisms claimed on product label and meeting all current EPA regulations for product registration. These types of disinfectant products should be used on environmental surfaces on a regular basis and/or when surfaces are visibly soiled with bioburden. All QAC-based formulated surface disinfectant products contain specific manufacturer’s instructions for use that illustrate the proper use of the disinfectant product. As an example, a surface disinfectant product should appear visibly wet and allowed to dry for the allotted time outlined by the manufacturer in order to meet efficacy claims. These instructions are imperative to ensure the compatibility, stability, efficacy and safety tested under EPA guidance are provided to all areas treated. Included in these instructions is the proper handling of each product based on the safety and toxicity classification. All EPA products have been tested and contain labeling outlining these best practices for handling disinfectant products.
- Jaime M. Ferreira, PhD, PDI research and development
ICT: What should healthcare professionals know about contact/dwell times and the use of quats?

Dwell times can vary from 3 to 10 minutes across brands, or concentrations used. Professionals should check the label to clearly understand the amount of time a surface must remain wet to ensure the disinfection is effective. A 10-minute contact time can be difficult to achieve with one application. A second (or third) application may be indicated to achieve the wet contact time required for the quat to be effective against the microorganisms listed on the label. This, coupled with ensuring that all high-touch surfaces are cleaned on a daily basis are both key best practices. Disinfectants requiring a shorter dwell time can help improve compliance and productivity. A faster contact time can also reduce the risk of slip and falls as floors will need to stay wet for a shorter time.
- Jim Gauthier, senior clinical advisor, infection prevention, Diversey Care

Contact time or dwell time is an important parameter to look for on the product labels. Since it is nearly impractical for us to detect the kinds of pathogens on the inanimate surfaces, universal precaution is a good practice here. That being said, we need to follow the longest contact time on the product labels to achieve the claimed efficacies. By law, the user must follow all applicable label instructions on EPA-registered products. If the user selects exposure conditions that differ from those on the EPA-registered product label, the user assumes liability for any injuries resulting from off-label use and is potentially subject to enforcement action under FIFRA.1

1. CDC. 2009.
- Yatao Liu, PhD, director of worldwide clinical affairs and business development, Metrex 

The contact/dwell times provided by each manufacturer of disinfectant products are required on the product label. These contact times are established by the highest time value needed to mitigate any or all of the microorganisms claimed by the product’s EPA master label. The master label contains all the claims associated with the product versus the product label is the relevant claims the manufacturer provides for that product. These contact times are established during product efficacy testing versus each specific microorganism and provide the necessary time needed for the surface to remain visibly wet. These contact times are tested follow strict EPA guidelines under good laboratory practice, therefore adhering to these requirements are imperative to ensure proper efficacy, safety, and compatibility.
- Jaime M. Ferreira, PhD, PDI research and development


ICT: What are the benefits of advanced hydrogen peroxide over other chemicals for surface disinfection in healthcare facilities?

AHP® helps hospitals reduce healthcare-associated infections (HAIs), an expensive, dangerous problem that becomes more serious each year. Today’s disinfecting technologies actually contribute to this problem by allowing hospitals to think they’re cleaner than they are. Another concern with many of the disinfectants used today are the threat they pose to human health such as association of quaternary ammonium compounds (QUATs) or chlorine releasing compounds such as bleach with increased rates of occupational asthma.  The Accelerated Hydrogen Peroxide® (AHP®) technology has been designed to combat the current shortcomings of other disinfectant technologies. AHP® is a synergistic blend of low levels of hydrogen peroxide, surfactants and other inerts that when combined together provide the perfect balance between safety and efficacy.  With only one application needed for efficient pathogen kill and compliance with federal regulations the patented technology uses the power of oxidation to clean and disinfect surfaces as it dries slowly to ensure disinfection has occurred. Lastly, AHP® is a non-hazardous cleaner and disinfectant that is gentle on people, equipment and the environment. AHP® has been proven to be non-toxic and non-irritating to the skin and eyes and does not require the use of personal protective equipment (PPE) at the in-use dilutions. Furthermore, AHP® does not produce any noxious fumes and is fragrance free and the active ingredient in AHP® is hydrogen peroxide which breaks down into oxygen and water and leaves no active residues behind ensuring it will not negatively impact indoor air quality or the environment.
- Olivia Lattimore, clinical and technical services specialist, Virox Technologies Inc.

ICT: What are some examples of the superior efficacy of AHP?

The efficacy of AHP® has been supported by over 30 clinical studies, articles, and research abstracts. In a more recent study by Alfa, et al.1 published in the American Journal of Infection Control, the data showed that daily use of AHP® applied to patient care high-touch environmental surfaces with a minimum of 80 percent cleaning compliance led to a 20 percent reduction in HAIs including MRSA, VRE and Clostridium difficile and led to significant cost savings to the facility. Another study by Maillard, et al. published in the Journal of Hospital Infection, demonstrated how AHP® was able to produce at least a 7.0 log reduction (99.99999 percent) against Staphylococcus aureus and Acinetobacter baumannii. Additionally, AHP® was the only disinfectant used in the study that was able to prevent the transfer of bacteria to other surfaces,2 which is an important component in reducing the transmission of harmful pathogens and reducing HAIs. Furthermore, a study published in Infection Control and Hospital Epidemiology by Rutala, et al. illustrates AHP’s superiority in comparison to standard hydrogen peroxide and quats as it was able to produce a 6.0 log reduction (99.9999 percent) in 30 seconds against MRSA, VRE and Acinetobacter baumannii.

1. Alfa, MJ. et al. Use of a daily disinfectant cleaner instead of a daily cleaner reduced hospital-acquired infection rates. AJIC 43 (2015) 141-6.
2. Sattar, SA. et al. Disinfectant wipes are appropriate to control microbial bioburden from surfaces: use of a new ASTM standard test protocol to demonstrate efficacy. J Hosp Infect. 2015 Dec; 91(4):319-25. doi: 10.1016/j.jhin.2015.08.026.
- Olivia Lattimore, clinical and technical services specialist, Virox Technologies Inc.

ICT: What are some best practices for handling and using AHP?

Disinfection of surfaces is a vital part of any facility’s infection prevention and control program. Choosing a product that provides realistic contact times and is easier for staff to use is a key component of ensuring an effective disinfection program. AHP® is a non-hazardous cleaner-disinfectant that is gentle on people, equipment and the environment. AHP® products do not require the use of PPE at in use dilutions, as AHP® is non-irritating to the eyes or skin, nor is it a respiratory irritant. The ease of use helps ensure user compliance, however; establishing clear roles and responsibilities for who is responsible for cleaning each surface or piece of equipment found in a patient room is imperative to ensure success. Once the responsibilities have been assigned it is imperative that all staff are trained in how to use the product correctly. AHP’s patented technology allows it to stays wet on surfaces longer: Only one application needed for efficient pathogen kill and compliance with federal regulations simplifying training.
- Olivia Lattimore, clinical and technical services specialist, Virox Technologies Inc.

ICT: What should healthcare professionals know about contact/dwell times and the use of AHP?

Many of today’s disinfectants evaporate on surfaces before they have a chance to completely kill pathogens. With the emergence of new pathogens and increasing outbreaks with known pathogens, it is essential that disinfectants applied to surfaces reach their required contact times in order to achieve disinfection. A study by Omidbakhsh published in the Journal of AOAC International compared the ability of six disinfectant chemistries’ to remain wet long enough on the surface to reach the contact time stated on the product label. AHP® was the only disinfectant tested that exceeded the required contact time to achieve bactericidal and virucidal kill claims. All disinfectant product labels will state a specific length of time a surface must remain wet (also known as contact time) in order to achieve complete disinfection.  If a product doesn’t remain wet on a surface long enough to reach its required contact time, repeat application is required in order to comply with federal regulations, however; studies show that this is not getting done consistently.1 The unique AHP® technology ensures surfaces stay wet longer: only one application is needed for efficient pathogen kill and compliance with federal regulations. Ready to use AHP® products have a one-minute kill time for most pathogens, including tough-to-kill viruses like norovirus.

1. Omidbakhsh N. Theoretical and Experimental Aspects of Microbicidal Activities of Hard Surface Disinfectants: Are Their Label Claims Based on Testing Under Field Conditions? J AOAC Int. 2010; Vol. 93 (6):1-8. 
- Olivia Lattimore, clinical and technical services specialist, Virox Technologies Inc.


ICT: What should healthcare professionals know about disinfectants and the potential for resistance/reduced sensitivity by microorganisms?

Resistance to antimicrobial agents, especially antibiotics, is a major public health concern throughout the world. Surface disinfectants often have multiple, non-specific target sites across different classes of microorganisms. For example, oxidative disinfectants like sodium hypochlorite and hydrogen peroxide quickly and indiscriminately react with proteins, nucleic acids and other biomolecules, leading to oxidative cell destruction. This makes it challenging for pathogens to develop mechanisms to survive exposure to these surface disinfectants.
Compliant cleaning and disinfection of environmental surfaces and medical equipment is an important  first line of defense to prevent the spread of HAI-causing pathogens, both antibiotic resistant organisms like methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Enterobacteriaceae (CRE), pathogens associated with antibiotic usage like C. difficile, as well as other pathogens in the healthcare environment.
- Sarah C. Bell-West, PhD, senior scientist in research and development with Clorox Healthcare
Healthcare professionals should be aware that there is a hierarchy of resistance to disinfectants, with spores being the hardest to kill in the healthcare environment, and enveloped viruses being the easiest. If a disinfectant with label claims for bacteria and viruses is used at the proper concentration for the proper dwell time, there should be no issue achieving successful disinfection. Unlike antibiotics that work in a different manner than disinfectants, it is unlikely that disinfectants will develop resistance if used properly.
- Jim Gauthier, senior clinical advisor, infection prevention, Diversey Care
With the increasing threat to public health by antibiotic-resistant microorganisms or multidrug-resistant microorganisms (MDROs), we have to be more careful in appropriate use of antibiotics. Then how about disinfectants? From the selection pressure mechanisms, unlike antibiotics, disinfectants are generally non-specific interactions with microorganisms such as increasing binding affinity.1-2 targeting on physically disrupting cell membranes leading to cell lysis. In addition, quat-based surfactants generally contain a few active ingredients, which can form synergy and yield an intricate antimicrobial mechanisms. Thus it is hard for microorganisms to mutate in order to develop a bypath to avoid this non-specific attacks. Even with the use of disinfectants for decades, disinfectant-resistant microorganisms are rarely reported in clinical settings. However, this topic has attracted increasing amount of research. Disinfectant-resistant genes (qacA/B) have been reported in MRSA.3 This study also concluded that the presence of the qacA/B disinfectant resistance genes did not lead to resistance to the disinfectant substances at the concentrations used in clinical practices.
Other studies have reported that disinfectant genes are found in Pseudomonas, Enterococcus4 and Acinetobacter baumannii.5 The increase of resistance usually measured by minimum inhibitory concentration (MIC); however, the MIC is far below the disinfectant concentrations used in clinical practices.
Even if we do not have an immediate concern or need to change our use of disinfectants, we need to monitor and conduct more systematic studies. We certainly will closely review all the scientific findings to improve our product innovation and provide the best knowledge to healthcare professionals.

1. Wang KF, Nagarajan R, Camesano TA. Differentiating antimicrobial peptides interacting with lipid bilayer: Molecular signatures derived from quartz crystal microbalance with dissipation monitoring. Biophys Chem 2015;196:53-67.
2. Liu Y, Strauss J, Camesano TA. Adhesion forces between Staphylococcus epidermidis and surfaces bearing self-assembled monolayers in the presence of model proteins. Biomaterials 2008;29:4374-82.
3. Aykan SB, Caglar K, Engin ED, Sipahi AB, Sultan N, Cirak MY. Investigation of the Presence of Disinfectant Resistance Genes qacA/B in Nosocomial Methicillin-Resistant Staphylococcus aureus Isolates and Evaluation of Their In Vitro Disinfectant Susceptibilities. Mikrobiyol Bul 2013;47:1-10.
4. Bischoff M, Bauer J, Preikschat P, Schwaiger K, Molle G, Holzel C. First Detection of the Antiseptic Resistance Gene qacA/B in Enterococcus faecalis. Microb Drug Resist 2012;18:7-12.
5. Chalbaud A, Ramos Y, Alonso G. Antibiotic and Disinfectant Resistance in Acinetobacter baumannii genotyped isolates from the Caracas University Hospital. Microbes in Applied Research: Current Advances and Challenges 2012:481-5.
- Yatao Liu, PhD, director of worldwide clinical affairs and business development, Metrex 

 A misconception is that QACs lose effectiveness when mixed with organic matter, such as blood, and/or in the presence of hard water. In fact, advances in the area of formulation science allow for surfactants and modifiers to be introduced into the formulation as inerts to provide for improved effectiveness and cleaning performance for blood, urine, and other soil types found on surfaces.
Another important misconception is that continuous use of QAC-based chemistries results in the development of antimicrobial resistance, but recent publications have proved this to be untrue when disinfectants are used according to manufacturer’s instructions for use.1-3 These recent reviews provide evidence and basic theory based on the mode of attack that QACs utilize that it is highly unlikely it would lead to treatment failure. In addition, a study conducted by Meyers C. in 2010, provided data that rotating different QAC formulations in healthcare reduce the risk or the probabilities that environmental treatment would improve.4 Research regarding resistance to biocides, specifically QAC-based formulations, has not provided evidence to substantiate this resistance theory. In most instances, the root cause associated with these false positives stem from incorrect handling of product, sample preparation and human error.2 In addition, with the evolution of QACs from generation-1 to most recent generation-7 formulations developed specifically for disinfectants are even less susceptible to resistance due to these enhanced properties.

1. Rutala WA, Gergen MF, Weber DJ. 2007. Microbiologic evaluation of microfiber mops for surface disinfection.AmJ Infect Control 35:56973.
  2. Gilbert P, McBain AJ. 2003. Potential impact of increased use of biocides in consumer products on prevalence of antibiotic resistance. Clin Microbiol Rev 16:189–208.
  3. Weber DJ, Rutala WA, Sickbert-Bennett EE. 2007. Outbreaks associated with contaminated antiseptics and disinfectants. Antimicrob Agents Chemother 51:4217–4224.
4.  Meyer B, Cookson B. 2010. Does microbial resistance or adaptation to biocides create a hazard in infection prevention and control? J Hosp Infect
- Jaime M. Ferreira, PhD, PDI research and development

There are some disinfectant actives that can contribute to antimicrobial resistance such as those products that use triclosan. Of major concern is the possibility that triclosan resistance may contribute to reduced susceptibility to clinically important antimicrobials, due to either cross-resistance or co-resistance mechanisms.1 Additionally, quaternary ammonium compounds (quats) have been identified in contributing to antibiotic resistance through both cross-resistance and co-resistance, partially because quats leave an active residue behind on surfaces which can build up over time giving microorganisms a chance to build up resistance.2 However, due to the rapid kill times of surface disinfectants, the likelihood of bacteria developing resistance to surface disinfectants is low. In regards to antibiotic resistance, antibiotics have very specific targets where they attack the bacteria just as a lock needs a specific key in order to open. Disinfectants are not specific in their attack, making resistance much more difficult. When it comes to preventing antibiotic resistance, manual surface disinfection is essential for removing soils and killing pathogens of concern on surfaces, but the product must be used properly according to the label. AHP® does not leave any active residues on surfaces which can lead to resistance and contains efficacy claims against both antibiotic resistant and non-resistant pathogens.

1. Yazdankhah SP, Scheie AA, Høiby EA, Lunestad BT, Heir E, Fotland TØ, Naterstad K, Kruse H. Triclosan and antimicrobial resistance in bacteria: an overview. Microb Drug Resist. 2006 Summer; 12(2):83-90
2. Hegstad K, Langsrud S, Lunestad BT, Scheie AA, Sunde M, Yazdankhah SP. Does the wide use of quaternary ammonium compounds enhance the selection and spread of antimicrobial resistance and thus threaten our health? Microb Drug Resist. 2010 Jun; 16(2):91-104.
- Olivia Lattimore, clinical and technical services specialist, Virox Technologies Inc.