by Henry L. Carbone, BS, MS

Clostridium difficile infections (CDI) are a major concern in healthcare settings and are becoming more frequent, more severe, and more difficult to treat. A species of Gram-positive bacteria, Clostridium difficile causes diarrhea and other intestinal disease such as colitis when competing bacteria are wiped out by antibiotics. In its vegetative form, the bacterium is a strict anerobe and dies rapidly in the presence of oxygen. However, in the environment it can sporulate, enabling survival for months and resistance to many cleaning and disinfection practices.¹ It’s estimated that up to $3 billion annually is spent in the United States on managing cases of CDI, associated with increased lengths of hospital stay, increased costs, morbidity and mortality among adult patients.²

While most healthcare facilities already have specific cleaning and disinfection practices in place to deal with C. difficile outbreaks, the U.S. Environmental Protection Agency (EPA) has started to approve hard surface disinfectant solutions with claims against C. difficile spores and these products bear consideration.

The most recent guidelines for control and remediation of C. difficile in acute care settings were published by the Centers for Disease Control and Prevention (CDC) and the Association for Professionals in Infection Control and Epidemiology (APIC) in early 2008. At that time, the U.S. Environmental Protection Agency (EPA) had not approved a C. difficile spore claim for any hard surface disinfectant product. The first such claim was granted in November 2008, well after the guidelines had been published. The guidelines therefore recommend meticulous cleaning with EPA-approved germicides for non outbreak situations and meticulous cleaning combined with use of a 10 percent hypochlorite bleach solution (~5000ppm available chlorine) in outbreak situations.^3,4 While not backed by an EPA approval, this recommendation is supported by research studies as cited in both the CDC and APIC guidelines.

Since the first C. difficile spore claim was granted (EPA registration number 67619-8), at least two other products have been approved (EPA registration numbers 1677-226 and 81073-3)⁵ and it is reasonable to expect that more products will be approved in the future.

It is important to note that disinfectant products approved by the EPA undergo stringent efficacy and stability testing to ensure that they are effective at killing the micro-organisms listed on their label when used in accordance with label instructions.⁶ Facilities using products that do not bear an EPA claim against C. difficile spores, such as store brand bleach, do so at their own risk as these products have not gone through the testing process to validate efficacy. A specific example of this risk is the strength of the disinfectant used. Concentrated bleaches sold in stores generally range in strength from 3 percent to 6 percent hypochlorite and may have variable shelf stability of the active ingredient. Both of these can have a significant impact on the strength of the product during use. To ensure stability and efficacy, healthcare facilities are strongly encouraged to only use EPA-registered hard surface disinfectants with label claims against C. difficile spores for control and remediation of C. difficile.

One of the three products with an EPA approved claim against C. difficile spores uses sodium hypochlorite as an active ingredient while the other two use peracetic acid. The different active ingredient systems offer different levels of material compatibility, cleaning cloth compatibility, stability in the presence of organic soil, use dilution shelf stability and odor profiles. For example, a peracetic acid based product will not bleach fabrics like a hypochlorite based product would. Healthcare facilities can consider this information, which is typically available from the manufacturer, and other factors such as the surfaces it will be used on, when selecting a product for use in control of C. difficile spores.

Product delivery format is another important factor for facilities to consider because it ties so closely with the time needed for the sporicidal disinfectant solution to be effective. Disinfectant products are generally available in ready-to-use (RTU), dilutable concentrate, or disposable wipe formats. As of this writing, none of the products with EPA registration for C. difficile spore efficacy are available in disposable wipe format. Facilities using bleach wipes for their C. difficile control programs are using the products for a purpose not approved by the EPA. With respect to RTU vs. concentrate formats, concentrates generally have a lower cost per use quantity, but RTU products offer enhanced convenience and better use dilution stability. The convenience and stability of RTUs may be an advantage for facilities that only have sporadic need for a product with C. difficile spore efficacy.

Whatever solution a healthcare facility decides to use, the pre-cleaning step is critical for remediation of C. difficile spores because it maximizes the effectiveness of the sporicidal disinfectant. The EPA requires all products with efficacy against C. difficile spores to bear the following instructions for pre-cleaning:

“Fecal matter/waste must be thoroughly cleaned from surfaces/objects before disinfection by application with a clean cloth, mop, and/or sponge saturated with the disinfectant product. Cleaning is to include vigorous wiping and/or scrubbing, until all visible soil is removed. Special attention is needed for high-touch surfaces. Surfaces in patient rooms are to be cleaned in an appropriate manner, such as from right to left or left to right, on horizontal surfaces, and top to bottom, on vertical surfaces, to minimize spreading of the spores. Restrooms are to be cleaned last. Do not reuse soiled cloths.”⁷

There may be other non-spore pathogens present during pre-cleaning, so it is advisable to use a one-step cleaner/disinfectant (i.e. efficacy in the presence of organic soil) in the pre-cleaning step. If the product used for C. difficile spore removal also has a one-step cleaner/disinfectant claim for non-spore organisms it may be used in the pre-cleaning step to simplify the process for environmental service workers. Because as C. difficile is shed in fecal matter, bathrooms must be a focus area for thorough cleaning/disinfection, particularly to toilets, bedpans, bedpan cleaners, as well as any hand touch objects such as light switches, grab bars, flush handles and sink fixtures.

Due to the risk of surface-to-hand and hand-to-surface transferall high touch objects in the patient room should receive similar attention with surfaces pre-cleaned with an EPA-registered one-step cleaner/disinfectant, followed by disinfection with an EPA-registered disinfectant with efficacy against C. difficile spores. These include over bed tables, bed side tables, soap dispensers, bed rails, telephones, call buttons, TV remote controls, etc.⁸

Healthcare facilities should also implement a cleaning monitoring program to ensure that all appropriate surfaces are cleaned. A product with C. difficile spore efficacy does little to remediate C. difficile on surfaces if that surface is never cleaned. A number of studies have been published which show a reduction in rates of CDI when there is an increased focus on good environmental cleaning. A good environmental hygiene program would include:

• Training and education on best practices.
• The right products and tools for the specific application, in this case for remediation of C. difficile.
  • Due to the chemical resistance of spores, focus should be paid to ensure that the correct amount of disinfectant active ingredient is delivered to the surface.
  • The correct tools can improve efficiency of the cleaning process to ensure that the room is thoroughly cleaned while still meeting room turnover expectations.
  • The correct tools will facilitate good ergonomics and help prevent injury.
• Standardized cleaning processes and infection control practices.
  • Ensure that high touch objects are consistently cleaned and disinfected.
  • Provide controls to prevent cross contamination.
  • Provide objective metrics to ensure effectiveness of the cleaning program.

Numerous studies have been conducted on programs that apply these practices, although only a few focused on C. difficile. In all of the studies in which this method was used, the thoroughness of environmental cleaning was improved. ^8,9,10,11 Use of programs such as these to monitor and provide feedback on environmental cleaning are an important component of any program for control and/or remediation of C. difficile.

Appropriate attention should be placed on environmental cleaning and disinfection as the environment has been shown to be a transmission vector for C. difficile infections.¹² With the advent of EPA approval for hard surface disinfectants with efficacy against C. difficile spores, facilities are encouraged to incorporate these products into their cleaning/disinfection practices. EPA registration provides assurance of efficacy and stability when the products are used in accordance with their label directions. When selecting a sporicidal disinfectant facilities should consider material compatibility, cleaning cloth compatibility, stability, odor profile, product form, and whether or not the product is appropriate for use in the pre-cleaning step. Facilities should also implement a cleaning monitoring program to ensure that their processes make the best use of the hard surface disinfectant with C. difficile spore efficacy that they select.

References

1. Kim KH, Fekety R, Batts DH, Brown D, Cudmore M, Silva J Jr, Waters D. Isolation of Clostridium difficile from the environment and contacts of patients with antibiotic-associated colitis. J Infect Dis. 1981;143(1):42-50.
2. Dubberke ER, Wertheimer, AI. Review of Current Literature on the Economic Burden of Clostridium difficile. Infection. Infect Control Hosp Epidemiol 2009; 30:57-66.
3. Carrico RM, Archibald LK, Bryant K, et al. Guide to the elimination of Clostridium difficile in healthcare settings. Washington, DC: Association for Professionals in Infection Control and Epidemiology, Inc.; 2008.
4. Rutala WA, Weber DJ, and the Healthcare Infection Control Practices Advisory Committee (HICPAC). Guidelines for disinfection and sterilization in healthcare facilities, 2008.  Available from: http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf Accessed February 23, 2010.
5. http://oaspub.epa.gov/pestlabl/ppls.home
6. US Environmental Protection Agency, Pesticide Assessment Guidelines Subdivision G Product Performance (Washington, DC: US Environmental Protection Agency, 1982).
7. US Environmental Protection Agency. Guidance for the Efficacy Evaluation of Products with Sporicidal Claims against Clostridium difficile. 2009. Available from: http://www.epa.gov/oppad001/cdif-guidance.html. Accessed March 30, 2010.
8. Carling PC, Briggs JL, Perkins J, Highlander D. Improved cleaning of patient rooms using a new targeting method. Clin Infect Dis. 2006 Feb 1;42(3):385-8.
9. Goodman ER, Platt R, Bass R, Onderdonk AB, Yokoe DS, Huang SS. Impact of an environmental cleaning intervention on the presence of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci on surfaces in intensive care unit rooms. Infect Control Hosp Epidemiol. 2008 Jul;29(7):593-9.
10. Carling PC, Parry MM, Rupp ME, Po JL, Dick B, Von Beheren S; Healthcare Environmental Hygiene Study Group. Improving cleaning of the environment surrounding patients in 36 acute care hospitals. Infect Control Hosp Epidemiol. 2008 Nov;29(11):1035-41.
11. Po JL, Burke R, Sulis C, Carling PC. Dangerous cows: an analysis of disinfection cleaning of computer keyboards on wheels. Am J Infect Control. 2009 Nov;37(9):778-80.
12. Carrico RM, Archibald LK, Bryant K, et al. Guide to the elimination of Clostridium difficile in healthcare settings. Washington, DC: Association for Professionals in Infection Control and Epidemiology, Inc.; 2008.

Henry (Hank) L. Carbone is the Ecolab Healthcare Division’s Senior Research and Development Program Leader for Environmental Cleaning and Disinfection. His team is responsible for development and commercialization of novel products and systems used for surface cleaning and disinfection in healthcare settings. He can be reached at hank.carbone@ecolab.com.