A Clean Sweep:
Surface Cleaning in the Healthcare Environment
It is commonly accepted by infection control experts that although the healthcare environment serves as a reservoir for myriad microorganisms, it is rarely implicated in disease transmission except in the immuno-compromised patient population. It is imperative for members of the environmental services (ES) department to remember that microorganisms lie in wait in the likeliest and unlikeliest places.
According to the 2004 Guidelines for Environmental Infection Control in Health-Care Facilities: Recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC), Inadvertent exposures to environmental opportunistic pathogens (e.g., Aspergillus spp. and Legionella spp.) or airborne pathogens (e.g., Mycobacterium tuberculosis and varicella-zoster virus) may result in infections with significant morbidity and/or mortality. Lack of adherence to established standards and guidance can result in adverse patient outcomes in healthcare facilities.
Among the key recommendations is a mandate for environmental infection-control measures for special care areas with patients at high risk and for environmental surface cleaning and disinfection strategies with respect to antibiotic-resistant microorganisms.
MDROS and the Environment
Mary Brachman, RN, MS, CIC, of Brachman Associates, while presenting on hot topics in infection control at the recent American Society for Healthcare Environmental Services (ASHES) conference, reminded attendees of the prevalence of chemically resistant organisms, such as Clostridium diffi cile, as well as multidrug-resistant organisms (MDROs) such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). Brachman said that the hardest microbes to kill are prions and bacterial spores; intermediate resistance to disinfection is demonstrated by mycobacterium and non-enveloped viruses; and the easier to kill are fungi, vegetative bacteria such as Pseudomonas, and enveloped viruses.
The healthcare environment contains a diverse population of microorganisms, but only a few are significant pathogens for susceptible humans, according to the CDC guidelines. Microorganisms are present in great numbers in moist, organic environments, but some also can persist under dry conditions. Although pathogenic microorganisms can be detected in air and water and on fomites, assessing their role in causing infection and disease is difficult. Only a few reports clearly delineate a cause and effect with respect to the environment and in particular, housekeeping surfaces.
Eight criteria are used to evaluate the strength of evidence for an environmental source or means of transmission of infectious agents:
- The organism can survive after inoculation onto the fomite
- The organism can be cultured from in-use fomites
- The organism can proliferate in or on the fomite
- Some measure of acquisition of infection cannot be explained by other recognized modes of transmission
- Retrospective case-control studies show an association between exposure to the fomite and infection
- Prospective case-control studies may be possible when more than one similar type of fomite is in use
- Prospective studies allocating exposure to the fomite to a subset of patients show an assication between exposure and infection
- Decontamination of the fomite results in the elimination of infection transmission
An understanding of how infection occurs after exposure, based on the principles of the chain of infection, is also important in evaluating the contribution of the environment to healthcareassociated infections (HAIs).
The components of the chain of infection are:
- Adequate number of pathogenic organisms
- Pathogenic organisms of suficient virulence
- A susceptible host
- An appropriate mode of transmission or transferal of the organism in suficient number from source to host
- The correct portal of entry into the host
The presence of the susceptible host is one of these components that underscores the importance of the healthcare environment and opportunistic pathogens on fomites and in air and water.
General Cleaning Strategies for Patient-Care Areas
The number and types of microorganisms present on environmental surfaces are influenced by the following factors:
- The number of people in the environment
- The amount of activity
- The amount of moisture
- The presence of material capable of supporting microbial growth
- The rate at which organisms suspended in the air are removed
- The type of surface and orientation -- horizontal or vertical
Strategies for cleaning and disinfecting surfaces in patient-care areas take into account the following:
- The potential for direct patient contact
- The degree and frequency of hand contact
- The potential contamination of the surface with body substances or environmental sources of microorganisms, such as soil, dust, and water
Cleaning Housekeeping Surfaces
Housekeeping surfaces require regular cleaning and removal of soil and dust. Dry conditions favor the persistence of gram-positive cocci in dust and on surfaces, whereas moist, soiled environments favor the growth and persistence of gram-negative bacilli. Most, if not all, housekeeping surfaces need to be cleaned only with soap and water or a detergent/disinfectant, depending on the nature of the surface and the type and degree of contamination. Cleaning and disinfection schedules and methods vary according to the area of the healthcare facility, type of surface to be cleaned, and the amount and type of soil present.
Disinfectant/detergent formulations registered by the Environmental Protection Agency (EPA) are used for environmental surface cleaning, but the physical removal of microorganisms and soil by wiping or scrubbing is probably as important, if not more so, than any antimicrobial effect of the cleaning agent used. Therefore, cost, safety, product-surface compatibility, and acceptability by ES personnel can be the main criteria for selecting a registered agent. If using a proprietary detergent/disinfectant, the manufacturers instructions for appropriate use of the product should be followed. Consult the products material safety data sheets (MSDS) to determine appropriate precautions to prevent hazardous conditions during product application. Personal protective equipment (PPE) used during cleaning and housekeeping procedures should be appropriate to the task.
Housekeeping surfaces can be divided into two groups: those with minimal hand-contact, such as floors and ceilings, and those with frequent hand-contact, referred to as high touch surfaces. The methods, thoroughness, and frequency of cleaning and the products used are determined by healthcare facility policy; however, high-touch housekeeping surfaces in patient-care areas such as doorknobs, bedrails, light switches, wall areas around the toilet in the patients room, and the edges of privacy curtains, should be cleaned and/or disinfected more frequently than surfaces with minimal hand contact. Infection control practitioners (ICPs) typically use a risk-assessment approach to identify high-touch surfaces and then coordinate an appropriate cleaning and disinfecting strategy and schedule with the ES staff.
Horizontal surfaces with infrequent hand contact, including window sills and hard-surface flooring in routine patient-care areas, require cleaning on a regular basis, when soiling or spills occur, and when a patient is discharged from the facility. Regular cleaning of surfaces and decontamination, as needed, is also advocated to protect potentially exposed ES workers. Cleaning of walls, blinds, and window curtains is recommended when they are visibly soiled.
Part of the cleaning strategy is to minimize contamination of cleaning solutions and cleaning tools. Bucket solutions become contaminated almost immediately during cleaning, and continued use of the solution transfers increasing numbers of microorganisms to each subsequent surface to be cleaned; therefore, cleaning solutions should be replaced frequently. Another source of contamination in the cleaning process is the cleaning cloth or mop head, especially if left soaking in dirty cleaning solutions. Laundering of cloths and mop heads after use and allowing them to dry before re-use can help to minimize the degree of contamination. A simplified approach to cleaning involves replacing soiled cloths and mop heads with clean items each time a bucket of detergent/disinfectant is emptied and replaced with fresh, clean solution. Disposable cleaning cloths and mop heads are an alternative option, if costs permit.
Another reservoir for microorganisms in the cleaning process may be diluted solutions of the detergents or disinfectants, especially if the working solution is prepared in a dirty container, stored for long periods of time, or prepared incorrectly. Gram-negative bacilli such as Pseudomonas spp. and Serratia marcescens have been detected in solutions of some disinfectants. Application of contaminated cleaning solutions, particularly from small-quantity aerosol spray bottles or with equipment that might generate aerosols during operation, should be avoided, especially in high-risk patient areas. Making sufficient fresh cleaning solution for daily cleaning, discarding any remaining solution, and drying out the container will help to minimize the degree of bacterial contamination. Containers that dispense liquid as opposed to spray-nozzle dispensers can be used to apply detergent/disinfectants to surfaces and then to cleaning cloths with minimal aerosol generation. A pre-mixed, ready-to-use detergent/disinfectant solution also may be used.