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By Jamie Wolf
Articles documenting infection after improper reprocessing of patient-careitems and decontamination of surfaces have emphasized the need for appropriatecleaning and disinfection. Although most nosocomial infections result frompatients' endogenous flora or person-to-person transmission, contaminatedsurfaces also have been linked to nosocomial infection.1 When itcomes to environmental cleaning in healthcare settings, there are a wide rangeof products and procedures used. To implement evidence-based practices, it isimportant to have current information and background knowledge about the role ofthe environment in infection control.
The Contaminated Environment
Environmental surfaces may become contaminated with human pathogens, andextensive environmental contamination has been demonstrated in rooms of patientswith methicillin-resistant Staphylococcus aureus, 2, 3vancomycin-resistant Enterococcus (VRE) 4 and C. difficele.5 Environmental surfaces also can be contaminated with bloodbornepathogens, respiratory and enteric viruses, and other harmful microorganisms.There is little evidence that housekeeping surfaces such as floors and walls area direct source of infection for patients. 6
However, exposure to contaminated patient-care items such as rectalthermometers, commodes, and high-touch surfaces, have been implicated as asource of infection. 5 The transfer of microorganisms from theenvironment occurs through hand contact with these surfaces. Although theefficiency of direct transmission of microorganisms from surfaces has not beendefined in well-controlled studies, there is adequate evidence to support theneed for implementing good procedures for cleaning and disinfection ofhigh-touch surfaces. The level of disinfection and the type of cleaning agentrequired depends on factors such as: the surface classification, resistance ofthe microorganism to the chemical germicide, cost, safety, and ease of use.
In the 1970s, E.H. Spaulding developed a system to classify the cleaning,disinfection, and sterilization requirements for patient-care equipmentaccording to the risk of infection. The categories are as follows:
In the 1990s, the US Centers for Disease Control and Prevention (CDC)expanded Spaulding's original classification of non-critical medical equipmentand surfaces to more clearly define the risk of disease transmission fromcontact with these surfaces. 7 Environmental surfaces are defined ashousekeeping surfaces such as: floors, walls, beds, bed rails, bedside tables,and medical equipment surfaces such as: frequently touched adjustment knobs onx-ray machines, monitors, and instrument carts.
Along with the categorization of medical equipment, Spaulding also proposedthree levels of disinfection: high level, intermediate level, and low level. 8,9The basis for these levels is that microorganisms can be grouped according totheir innate resistance to physical or germicidal agents.
High-level destroys all microorganisms, with the exception of high numbers ofbacterial spores.
Intermediate level inactivates mycobacterium tuberculosis, vegetativebacteria, fungi, and lipid and nonlipid viruses. It does not kill resistantbacterial spores. It is equivalent to an EPA-registered, hospital-gradedisinfectant effective against mycobacterium, such as a phenolic or chlorine.
Low-level kills most vegetative bacteria, fungi, and lipid viruses, includinghepatitis B and HIV. It will not kill resistant spores or nonlipid viruses. Itis equivalent to a hospital-grade disinfectant that is not EPA-registered aseffective against mycobacterium, such as a quat.
Principles of Environmental Cleaning
Although disinfectant-detergent formulations registered by the EPA are usedfor environmental surface cleaning, the actual physical removal ofmicroorganisms and soil by scrubbing is probably as important, if not more so,than any antimicrobial effect of the cleaning agent used. 10
The activity of disinfectants against microorganisms depends on both theintrinsic qualities of the organisms (some are more innately resistant) whileothers depend on the chemical and physical environment. Key factors influencingthe effectiveness of cleaning and disinfection are:11
To determine the appropriate procedures for cleaning and disinfectingenvironmental surfaces, one should consider the following:
For most housekeeping and medical equipment surfaces, adequate safety levelscan be achieved by keeping the surfaces visibly clean using water and adetergent or a low-level disinfectant. For medical equipment surfaces heavilycontaminated with microorganisms such as bedpans and urine-measurementcontainers, cleaning which is then followed by application of a low orintermediate-level disinfectant may be appropriate. Housekeeping surfaces can bedivided into two groups--those with high-hand contact (bedrails, beds, overbedtables) and those with minimal hand-contact (floors and walls). High-touchsurfaces should be cleaned/or disinfected more frequently than surfaces withminimal hand-contact. 6
Cleaning frequency and methods vary according to the area of the hospital.Emphasis should be placed on the high-hand contact surfaces and patient careareas housing patients at greatest risk of infection, such as: ICU, oncology,dialysis, and surgery. Physical removal of microorganisms and soil by scrubbingis more important than the antimicrobial effect of the cleaning solution.Therefore, the acceptance by cleaning personnel, safety, and cost are the maincriteria for selecting cleaning solutions.
Myths and Misperceptions
Common misperceptions often abound when choosing the proper disinfectant forthe job. Some practitioners believe that using a phenolic or chlorine is theonly way to comply with the OSHA bloodborne pathogens standard. However, afacility also can comply with OSHA by using a quat disinfectant with an HIV/HBVlabel claim. Studies have shown that hepatitis B and HIV are inactivated byquaternary ammonium compounds.12, 13 Cleaning with a quat is costeffective and allows for a streamlined cleaning process.
Although it is important--both aesthetically and to reduce the microbial loadto a safe level--to regularly clean housekeeping surfaces such as floors andwalls, these surfaces have not been directly linked to nosocomial infections.Maintaining these surfaces in a state of visible cleanliness, using a generalpurpose or neutral cleaner, will provide an adequate level of safety.
Environmental cleaning is an important part of breaking the chain ofinfection. There are a variety of disinfectants available to combat infectiousmicroorganisms. Infection control professionals (ICPs) and patient-care staffshould work together to identify the high-touch surfaces and then determine theappropriate chemical germicide, cleaning method, and schedule. Nosocomialinfections can cause significant morbidity, lengthen a patient's hospital stay,and increase the cost of healthcare. By maintaining a clean environment,healthcare facilities can reduce the risk of cross-contamination and infection.
Jamie Wolf is the healthcare marketing manager for the 3M Commercial CareDivision in St. Paul, Minn.
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