The Challenges of Infection Control
Environmental surface disinfection plays a critical role in preventing the transmission of infection in the dental setting.
Outpatient dental offices and clinics serve a unique purpose in the healthcare delivery system, providing vital basic oral care to millions of patients a year. Along with that unique purpose, unique challenges exist for infection control and prevention in the dental setting. Unlike the acute-care hospital setting, the dental environment does not require the presence of a dedicated infection-control officer; therefore, in most practices and clinics, this responsibility is delegated to a lead hygienist, dental assistant, practice manager, or even the dentist. This is an additional responsibility that requires specific training in infection control and prevention, as well as annual updates on certain topics such as bloodborne pathogens.
Because of the high risk for potential bloodborne pathogen exposure, dental healthcare workers (DHCWs) must take a number of precautions to mitigate the risk for exposure to dangerous bloodborne pathogens, including human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). In addition to the well-documented risk for bloodborne pathogen exposure, DHCWs should also be concerned with occupational exposure and the transmission of drug-resistant organisms such as methicillin-resistant Staphylococcus aureus (MRSA).
While hand hygiene remains the single most important strategy in reducing the risk of infection transmission, the environment also plays a critical role in the transmission of infection and in microbial growth. Cleaning, disinfection, and sterilization are the three fundamental steps in the environmental hygiene process. Several factors impact the efficacy of both disinfection and sterilization, including: previous cleaning of the object; the organic and inorganic load present on the object; the type and level of microbial contamination; concentration of and exposure time to germicide; the physical nature of the object (eg, crevices, hinges, and lumens); the presence of biofilms; temperature and pH level of the disinfection process; and, in some cases, the relative humidity of the sterilization process (eg, ethylene oxide).1
Step One: Cleaning
Cleaning is the removal of visible soil (eg, organic and inorganic material) from objects and surfaces, and is accomplished manually or mechanically using water with detergents or enzymatic products. Thoroughly cleaning instruments before initiating high-level disinfection and sterilization procedures is essential because organic and inorganic materials that remain on instrument surfaces interfere with the effectiveness of these processes.
Step Two: Disinfection
Disinfection, as defined by the Centers for Disease Control and Prevention’s (CDC) Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008, is a process that eliminates many or all pathogenic microorganisms, except bacterial spores, on inanimate objects (Table 1).2 In healthcare settings, instruments, equipment, and other objects are usually disinfected with liquid chemicals or wet pasteurization. Reducing and/or preventing infection through indirect contact requires decontamination (ie, cleaning, sanitizing, or disinfecting an object to render it safe for handling) of patient equipment, medical devices, and the environment. Alternatively, the DHCW also may consider using single-use devices. The choice of decontamination method depends on the level of infection risk to the patient coming into contact with the equipment or medical device (Figure 1 and Figure 2).
The CDC has adopted the Spaulding classification system,3 which identifies three risk levels associated with medical and surgical instruments—critical, semi-critical, and noncritical, described as follows:
• Critical items (eg, needles, sterile syringes, and dental instruments) are defined as items that enter sterile tissue, the vascular system, or the circulatory system, and, therefore, must have been sterilized in one of several accepted sterilization procedures before being used in patient care.
• Semi-critical items (eg, thermometers and dental dams,) are defined as objects that touch mucous membranes or non-intact skin. These items require meticulous cleaning followed by high-level disinfection treatment using a Food and Drug Administration (FDA)-approved chemo-sterilizer agent. They also may be sterilized.
• Non-critical items (eg, pulse oximeters, procedure trays, patient chairs, countertops, operatory overhead lights, equipment processing areas, tops of autoclaves) are defined as objects that either come into contact with intact skin or do not contact the patient at all. They require low-level disinfection by cleaning periodically and after visible soiling with an Environmental Protection Agency (EPA)-registered disinfectant detergent or germicide labeled for use in a healthcare setting.
Criticality of Broad-Spectrum Efficacy Claims
Manufacturers of disinfectants are required to list detailed information regarding efficacy claims and contact time for each class of microorganisms for which the product is effective; this typically includes the classes of bacteria (both gram-positive and gram-negative), viruses, mycobacterium (TB), and fungi.4 In accordance with the EPA’s current requirements, labels must also provide detailed information on the product’s effectiveness against bloodborne pathogens, including HIV, HBV, and HCV.2 In the dental setting, the provider will most likely not be aware of types of colonization or potential active infection that a patient may or may not have; therefore, the use of a broad-spectrum healthcare disinfectant is paramount.
When evaluating a new or existing disinfectant, the person responsible for infection control should review the full listing of efficacy claims available from the product’s manufacturer. It is also important to review other ancillary materials such as the Material Safety Data Sheet (MSDS) and instructions-for-use documents. Product labels typically list efficacy claims by class of microorganism, including bacteria, viruses, Mycobacterium (including M tuberculosis, [TB]), and fungi.
The broader the spectrum of a product’s efficacy, the more effective the product will be against a wide variety of gram-positive and gram-negative bacteria. In addition, with the continual emergence of new—and mutations of existing—multi-drug resistant organisms (MDROs), DHCWs should seek products with broad general bactericidal efficacy, but which have also demonstrated effectiveness against organisms such as: multi-drug resistant Acinetobacter baumannii; extended-spectrum β-lactamases-producing organisms such as Escherichia coli; and carbapenem-resistant organisms such as Klebseilla pneumonia.3 Products with efficacy against these more resistant pathogens will assist the DHCW in combatting the daily threats of these microorganisms.
Viruses—particularly the bloodborne pathogens and those with the potential for causing outbreaks (ie, norovirus, influenza, and rotavirus)—are also of concern to users of healthcare disinfectants.5 The DHCW should require claims against bloodborne pathogens such as HIV, HBV, and HCV for any product that will be used in the healthcare environment. Also, seek products with other efficacy claims including enveloped and non-enveloped viruses where appropriate.5 Note that products may have different contact times for viruses than for bacteria.6
Products effective against Mycobacterium are minimally considered intermediate-level disinfectants.1 TB is not tested in the laboratory setting for initial product approval because of the high pathogenicity and potential transmission of this organism to the laboratory worker. Rather than put laboratory workers at risk, a surrogate organism—typically Mycobacterium bovis—is used for testing procedures.
Increasingly more prevalent in the healthcare environment are fungal organisms such as Candida albicans and Aspergillus.7 When evaluating fungal efficacy claims, seek products with efficacy against pathogenic fungal organisms that are clinically relevant based on the typical patient profile.
Overall Contact Time
Many manufacturers provide several contact times—one for bacteria, one for viruses, another for Mycobacterium, and possibly one for fungi. These contact times can vary greatly from 1 minute to 10 minutes. Because it is impossible for the user to determine the type of potential contamination that may exist on the surface to be treated, the user should disinfect the surface according to the longest contact time found on the product label to ensure full efficacy of the solution. For example, if a healthcare disinfectant has a 1-minute contact time for bacteria, a 2-minute contact time for viruses including HIV, a 5-minute contact time for TB, and a 10-minute contact time for fungi, then the total contact time for the product when used correctly is 10 minutes.6
Balancing Disinfection with Patient Comfort
As previously discussed, disinfectants used in healthcare settings must have aggressive claims against a wide variety of both community- and healthcare-associated pathogens. Because of the nature of the outpatient dental practice setting, a wide variety of both pediatric and adult patients may be treated at the site. Patients may have comorbidities such as asthma, chronic obstructive pulmonary disease, or chronic sinusitis and bronchitis that require the use of fragrance-free disinfectant products to minimize the risk of respiratory irritation during their respective dental examination and treatment. With the recent advent of healthcare-grade, low-level disinfectants that are also fragrance-free, these sensitive patients may now experience a more customized and less irritating dental healthcare experience.
Step Three: Sterilization
The CDC’s Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008,2 defines sterilization as any process that effectively kills or eliminates transmissible agents from surfaces, equipment, articles of food or medication, or biological culture medium. Sterilization does not, however, remove prions. Sterilization can be achieved through a variety of methods.1,8
Sterilization is ineffective without proper prior cleaning. The amount of bioburden and the number, type, and inherent resistance of microorganisms—including biofilms—on items negatively affects the sterilization process. According to the Association for periOperative Registered Nurses’ Recommended Practices,9 one of the most critical measures for preventing surgical site infections (SSI) is to provide surgical items that are free of contamination at the time of use. This can be accomplished by subjecting them to cleaning and decontamination, followed by a sterilization process. Steam, ethylene oxide, low-temperature hydrogen-peroxide gas plasma, peracetic acid, ozone, and dry heat are the sterilization methods that are most commonly used in the healthcare environment.9 Sterilization provides the highest level of assurance that surgical items are free of viable microbes.
Specific pieces of medical equipment, such as oral endoscopes, may require specialized processes in order to effectively eliminate all microorganisms from the components of the equipment. As a specific example, endoscopes require several key steps for efficacious disinfection and/or sterilization, including: cleaning (physical cleaning of the lumen, all channels, brushing both the internal and external surfaces, and rinsing); disinfection with a high-level disinfectant per the manufacturer’s instructions; rinsing with sterile or filtered water; drying; and storing properly to ensure prevention of contamination prior to the next use. During any type of sterilization process, it is paramount to follow established protocols and manufacturer instructions during every step.2
The role of infection prevention in the dental clinic is constantly expanding, and with the addition of new regulatory requirements from various regulatory bodies this position will only increase in importance. Now is the time for dental practices and clinics to develop a comprehensive infection prevention program. Outpatient dental facilities must comply with many requirements from regulatory bodies such as the CDC and the Occupational Health and Safety Administration. These various infection-prevention regulations are continuously evolving; therefore, the DHCW must participate in routine continuing educational activities in order to maintain a complete knowledge of these requirements. Many organizations, such as the Association for Professionals in Infection Control and Epidemiology and the CDC, offer webinars and other online continuing education opportunities on hot topics such as MRSA and Clostridium difficile (c-diff), among others.
1. Rutala WA, Weber DJ. Healthcare Infection Control Practices Advisory Committee. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. Available at: www.cdc.gov/hicpac/Disinfection_Sterilization/toc.html. Accessed February 10, 2012.
2. Centers for Disease Control and Prevention. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. Available at: http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf. Accessed February 13, 2012.
3. Spaulding EH. Chemical disinfection and antisepsis in the hospital. J Hosp Res. 1972;9:5-31.
4. US Environmental Protection Agency. Label Review Manual. Available at: http://www.epa.gov/oppfead1/labeling/lrm/label-review-manual.pdf. Accessed February 13, 2012.
5. OSHA Bloodborne Pathogens Standard. OSHA FactSheet. Available at: http://www.osha.gov/OshDoc/data_BloodborneFacts/bbfact01.pdf. Accessed February 10, 2012.
6. US Department of Labor, Occupational Safety and Health Administration. 29 CFR Part 1910.1030. Occupational exposure to bloodborne pathogens, needlesticks and other sharps injuries; final rule. Federal Register 2001;66:5317-25. [As amended from and includes 29 CFR Part 1910:1030. Federal Register 1991;56:64174-82.]
7. Centers for Disease Control and Prevention (CDC), National Healthcare Safety Network (NHSN), 2011. Available at: http://www.cdc.gov/nhsn/cms-welcome.html. Accessed February 10, 2012.
8. Favero MS, Bond WW. Chemical disinfection of medical and surgical material [Chapter 43]. In: Block SS, ed. Disinfection, Sterilization and Preservation. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2001:881-917.
9. Association for periOperative Registered Nurses (AORN). Blanchard J, Burlingame B, eds. Perioperative Standards and Recommended Practices, 2011. Denver, Colorado: AORN, Inc., 2011.
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About the Author
J. Hudson Garrett Jr., PhD, MSN, MPH, ARNP, FNP-BC, VA-BC
Senior Director, Clinical Affairs
Orangeburg, New York