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It is commonly accepted by infection control expertsthat although the healthcare environment serves as a reservoir for myriadmicroorganisms, it is rarely implicated in disease transmission except in theimmuno-compromised patient population. It is imperative for members of theenvironmental services (ES) department to remember that microorganisms lie inwait in the likeliest and unlikeliest places.
According to the 2004 Guidelines for Environmental Infection Control inHealth-Care Facilities: Recommendations of CDC and the Healthcare InfectionControl Practices Advisory Committee (HICPAC), Inadvertent exposures toenvironmental opportunistic pathogens (e.g., Aspergillus spp. and Legionellaspp.) or airborne pathogens (e.g., Mycobacterium tuberculosis andvaricella-zoster virus) may result in infections with significant morbidityand/or mortality. Lack of adherence to established standards and guidance canresult in adverse patient outcomes in healthcare facilities.
Among the key recommendations is a mandate for environmentalinfection-control measures for special care areas with patients at high risk andfor environmental surface cleaning and disinfection strategies with respect toantibiotic-resistant microorganisms.
MDROS and the Environment
Mary Brachman, RN, MS, CIC, of Brachman Associates, while presenting on hottopics in infection control at the recent American Society for HealthcareEnvironmental Services (ASHES) conference, reminded attendees of the prevalenceof chemically resistant organisms, such as Clostridium diffi cile, aswell as multidrug-resistant organisms (MDROs) such as methicillin-resistant Staphylococcusaureus (MRSA) and vancomycin-resistant Enterococcus (VRE). Brachman saidthat the hardest microbes to kill are prions and bacterial spores; intermediateresistance to disinfection is demonstrated by mycobacterium and non-envelopedviruses; and the easier to kill are fungi, vegetative bacteria such asPseudomonas, and enveloped viruses.
The healthcare environment contains a diverse population ofmicroorganisms, but only a few are significant pathogens for susceptiblehumans, according to the CDC guidelines. Microorganisms are present ingreat numbers in moist, organic environments, but some also can persist underdry conditions. Although pathogenic microorganisms can be detected in air andwater and on fomites, assessing their role in causing infection and disease isdifficult. Only a few reports clearly delineate a cause and effect withrespect to the environment and in particular, housekeeping surfaces.
Eight criteria are used to evaluate the strength of evidence for anenvironmental source or means of transmission of infectious agents:
An understanding of how infection occurs after exposure,based on the principles of the chain of infection, is also important inevaluating the contribution of the environment to healthcareassociatedinfections (HAIs).
The components of the chain of infection are:
The presence of thesusceptible host is one of these components that underscores the importance ofthe healthcare environment and opportunistic pathogens on fomites and in air andwater.
General Cleaning Strategies for Patient-Care Areas
The number and types of microorganisms present on environmental surfaces areinfluenced by the following factors:
Strategies for cleaning and disinfecting surfaces in patient-care areas take into account the following:
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 onsurfaces, whereas moist, soiled environments favor the growth and persistence ofgram-negative bacilli. Most, if not all, housekeeping surfaces need to becleaned only with soap and water or a detergent/disinfectant, depending on thenature of the surface and the type and degree of contamination. Cleaning anddisinfection schedules and methods vary according to the area of the healthcarefacility, type of surface to be cleaned, and the amount and type of soilpresent.
Disinfectant/detergent formulations registered bythe Environmental Protection Agency (EPA) are used for environmental surfacecleaning, but the physical removal of microorganisms and soil by wiping orscrubbing is probably as important, if not more so, than any antimicrobialeffect of the cleaning agent used. Therefore, cost, safety, product-surfacecompatibility, and acceptability by ES personnel can be the main criteria forselecting a registered agent. If using a proprietary detergent/disinfectant, themanufacturers instructions for appropriate use of the product should befollowed. Consult the products material safety data sheets (MSDS) todetermine appropriate precautions to prevent hazardous conditions during productapplication. Personal protective equipment (PPE) used during cleaning andhousekeeping procedures should be appropriate to the task.
Housekeeping surfaces can be divided into two groups: those with minimalhand-contact, such as floors and ceilings, and those with frequenthand-contact, referred to as high touch surfaces. The methods,thoroughness, and frequency of cleaning and the products used are determined byhealthcare facility policy; however, high-touch housekeeping surfaces inpatient-care areas such as doorknobs, bedrails, light switches, wall areasaround the toilet in the patients room, and the edges of privacy curtains,should be cleaned and/or disinfected more frequently than surfaces with minimalhand contact. Infection control practitioners (ICPs) typically use arisk-assessment approach to identify high-touch surfaces and then coordinate anappropriate cleaning and disinfecting strategy and schedule with the ES staff.
Horizontal surfaces with infrequent hand contact, including window sills andhard-surface flooring in routine patient-care areas, require cleaning on aregular basis, when soiling or spills occur, and when a patient is dischargedfrom 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 cleaningsolutions and cleaning tools. Bucket solutions become contaminated almostimmediately during cleaning, and continued use of the solution transfersincreasing numbers of microorganisms to each subsequent surface to be cleaned;therefore, cleaning solutions should be replaced frequently. Another source ofcontamination in the cleaning process is the cleaning cloth or mop head,especially if left soaking in dirty cleaning solutions. Laundering of cloths andmop heads after use and allowing them to dry before re-use can help to minimizethe degree of contamination. A simplified approach to cleaning involves replacing soiled cloths and mopheads with clean items each time a bucket of detergent/disinfectant is emptiedand replaced with fresh, clean solution. Disposable cleaning cloths and mopheads are an alternative option, if costs permit.
Another reservoir for microorganisms in the cleaning process may be dilutedsolutions of the detergents or disinfectants, especially if the working solutionis prepared in a dirty container, stored for long periods of time, or preparedincorrectly. Gram-negative bacilli such as Pseudomonas spp. and Serratiamarcescens have been detected in solutions of some disinfectants.Application of contaminated cleaning solutions, particularly from small-quantityaerosol spray bottles or with equipment that might generate aerosols duringoperation, should be avoided, especially in high-risk patient areas. Makingsufficient fresh cleaning solution for daily cleaning, discarding any remainingsolution, and drying out the container will help to minimize the degree ofbacterial contamination. Containers that dispense liquid as opposed tospray-nozzle dispensers can be used to apply detergent/disinfectants to surfacesand then to cleaning cloths with minimal aerosol generation. A pre-mixed, ready-to-usedetergent/disinfectant solution also may be used.