Can disinfectant efficacy claims be achieved in practice?

Disinfectant Claims

• Products with specific claims for disinfection of environmental surfaces offer greater efficacy than generic disinfectants?

Can disinfection of environmental surfaces be achieved in practice?

• Unfortunately laboratory testing of disinfectants is not a reflection of how disinfectants are used in the health care environment.

• 2011 | September

• Cleaning and Maintenance Management

• When Disinfectants Fail: How Newer Technologies Can Help

• Discussing the downfall of disinfectants.

• Author: Dr. Benjamin Tanner

• Traditional disinfectants have undoubtedly prevented a great number of infections over the years.

• Regrettably, though, many outbreaks are still spread by contaminated surfaces, and the technical drawbacks of liquid disinfectants may be partially to blame for high facility-acquired infection rates in health care.

• Chemical disinfectants registered by the U.S. Environmental Protection Agency (EPA) kill microorganisms reliably in laboratory tests; there is no question about that.

• However, disinfectants routinely fail in practice.

• French et. al.showed that conventional disinfection failed to reduce the presence of methicillin-resistant Staphylococcus aureus (MRSA) on 66 percent of tested surfaces and Byers et al. found that conventional disinfection failed to reduce vancomycin-resistant enterococci (VRE) contamination in 15.9 percent of sampled sites.

• Most recently, Stibich et al. reported 33 bacteria per square centimeter "before cleaning" in rooms of a cancer center and a reduction to 27.4 bacteria per square centimeter after traditional terminal room cleaning and disinfection.

• The main reasons disinfectants fail in practice are described below:

• Product not applied liberally for the right amount of time

• Wrong active ingredient in use for the microorganism(s) of concern

• Contaminated surfaces are missed by cleaning staff.

• Dwelling / Contact Times the number one reason disinfectants fail in practice is that too little volume is applied to target surfaces, and liquid that is applied is not left there long enough to do its job.

• In laboratory testing, the ratioof liquid to surface area is enormous; if one wanted to use this same ratio to clean the high-touch surfaces in a single hospital room — to get true disinfection — about a gallon of product would be needed.

• The volume of product required to get true disinfection from liquid chemicals on a surface is simply not realistic in many cases.

• The reality is that hospital staff may only spend 10 minutes cleaning a room, so adhering to label-stated contact times is not practical in this context.

• Furthermore, disinfectant will run off vertical and other irregular surfaces during the proposed contact time and may simply evaporate before the proper dwell time is reached.

• A study conducted by Antimicrobial Test Laboratories LLC demonstrated what happens to the efficacy of a disinfectant chemical when used in a manner close to what is commonly observed in the field.

• The results of this controlled laboratory study showed that for ultra-low contact times, traditional disinfectants left many microorganisms behind on the surface.

• Dr. Benjamin Tanner is the principal of Antimicrobial Test Laboratories, an independent testing facility specializing in the research and development of antimicrobials, including disinfectants. Dr. Tanner holds a B.S. in Molecular Biology and a Ph.D. in Microbiology and Immunology from the University of Arizona, where he studied environmentally mediated disease transmission and assessed infection risks for workers.

Spread and persistence of Clostridium difficile spores during and after cleaning with sporicidal disinfectants

• Letters to the Editor / Journal of Hospital Infection 79 (2011) 93–98

• S. Ali*• G. Moore• A.P.R. Wilson• Department of Microbiology, University

College London Hospitals,• London, UK• Accepted by J.A. Child• Available online 19 July 2011

• This study highlights the limitations of two commercially available sporicidal disinfectants against C. difficile spores. Preliminary suspension tests confirmed that both sporicides exhibited sporicidal activity sufficient to pass EN 13704 standards (>3 log reduction in 60-min contact time) under clean conditions (data not shown).

However, when tested under practical in-use conditions, they failed to prevent the transfer of spores during cleaning, and failed to achieve a 3 log reduction in residual spore numbers after 60 min.

Our findings support those of others, and suggest that current validation standards used for the development of commercially available sporicides do not accurately reflect in-use practices.

Healthcare practitioners should take precautions to ensure that existing disinfectants have in-use sporicidal activity against C. difficile spores.

“ In use refers to how product is used in practice”

Consider converting to evidence based cleaning practices.

• Cleaning processes based on evidence of outcomes in your facilities.

• Consider ATP and microbial testing of cleaning processes.

• Focus on cleaning which has always been the most effective method of reducing environmental contamination.

• Apply a disinfectant after cleaning as insurance.We recommend generic sources of hypochlorite at 1000 ppm preferably with Health Canada registration with a DIN for use on hard non porous surfaces in health care facilities.

• French et. al.showed that conventional disinfection failed to reduce the presence of methicillin-resistant Staphylococcus aureus (MRSA) on 66 percent of tested surfaces and Byers et al. found that conventional disinfection failed to reduce vancomycin-resistant enterococci (VRE) contamination in 15.9 percent of sampled sites.

• Most recently, Stibich et al. reported 33 bacteria per square centimeter "before cleaning" in rooms of a cancer center and a reduction to 27.4 bacteria per square centimeter after traditional terminal room cleaning and disinfection.

• General purpose detergent and water or detergent wipes should be used for all routine cleaning. (If an item is heavily soiled, detergent and water is the preferred method).

• Converting to evidence based cleaning practices is safer, more effective and sustainable