By Chris Kosobud
While healthcare-acquired infections (HAIs) can come from numerous causative agents and may be carried by numerous modes of transmission, attention should be paid to the role of environmental surfaces throughout the facility especially those surfaces commonly considered as germ "hot spots."
The problem? Germs that can cause colds, flu, infections and other health problems can live on surfaces, just waiting to be picked up by unsuspecting (clean) hands. While nothing beats good old-fashioned handwashing as a way to break the chain of germ transmission, proper attention to surface sanitation can also help minimize the transfer of microorganisms that can occur via hand contact between contaminated surfaces and the people who touch them.
In fact, according to the Centers for Disease Control and Prevention (CDC), cleaning and disinfecting environmental surfaces in healthcare facilities is fundamental in reducing the potential contribution of those surfaces to the incidence of HAIs. In addition to proper hand hygiene, such cleaning and disinfecting can help to minimize the transfer of microorganisms that can occur via hand contact between contaminated surfaces and patients.
Environmental surfaces can be divided into two parts: medical equipment surfaces such as knobs or handles on machines, carts, and similar equipment, and housekeeping surfaces, such as floors, walls and tabletops. Housekeeping surfaces can be further divided into those with minimal hand contact (referred to as "low-touch" surfaces) and those with frequent hand contact ("high-touch" surfaces).
Some examples of low-touch housekeeping surfaces include:
Examples of high-touch housekeeping surfaces in patient care areas those that can be considered germ hot spots include:
Wall areas around the toilet
Restroom surfaces such as faucets, toilet handles, sinks or dispensers
Edges of privacy curtains
While these lists offer some initial guidance, its important to note that several factors influence the amount of germs that may be found on individual housekeeping surfaces. The number and types of microorganisms present on environmental surfaces are influenced by:
The number of people in the environment.
Amount of activity in the environment.
Amount of moisture (microorganisms are present in great numbers in moist organic environments, but some can also persist under dry conditions).
Presence of material capable of supporting microbial growth.
Rate at which organisms suspended in air are removed.
Type of surface and orientation (horizontal or vertical).
Even in the absence of visible soiling with blood and/or body fluids, housekeeping surfaces may serve as germ reservoirs in the chain of infection. In fact, methicillin-resistant Staphylococcus aureus (MRSA) can survive for weeks to several months on almost all surfaces, and may cause skin and surgical infections. Clostridium difficile bacteria can live for years on environmental surfaces. Vancomycin-resistant enterococci (VRE) bacteria are very hardy and can live for several days on surfaces. And noroviruses can survive on virtually any hard surface for up to 12 hours.
According to CDC guidelines, hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) have never been known to be transmitted from a housekeeping surface such as floors, walls or countertops. However, prompt removal and surface disinfection of an area contaminated by either blood or body substances is a sound infection-control practice and an OSHA requirement, according to the CDC.
Most, if not all, housekeeping surfaces require regular cleaning with soap and water or a detergent/disinfectant and removal of soil and dust, according to guidelines from the CDC. High-touch housekeeping surfaces in patient-care areas should be cleaned and/or disinfected more frequently than surfaces with minimal hand contact. Horizontal surfaces with infrequent hand contact require cleaning on a regular basis, when soiling or spills occur, and when a patient is discharged from the facility.
Cleaning (the removal of all foreign material such as dirt, body fluids, and lubricants from objects by using water with detergents or soaps and by washing or scrubbing the object) is the necessary first step of any sterilization or disinfection process. It is needed to render the environmental surface safe to handle or use by removing organic matter, salts, and visible soils all of which interfere with microbial inactivation. In fact, the physical action of scrubbing with detergents and surfactants and rinsing with water removes large numbers of microorganisms from surfaces.
After cleaning, disinfection may be performed to eliminate many or all microorganisms (except spores) from surfaces. A number of disinfectants may be used in healthcare facilities, including alcohols, hypochlorites, chlorohexidine, iodophors, hydrogen peroxide, phenolics, and quaternary amine compounds. Product labels should specify indications for proper use, along with antimicrobial claims. Check to make sure that the chemical has an EPA registration number on the label. Disinfectants should be applied to surfaces uniformly, and surfaces should remain wet for the length of time recommended by the manufacturer.
Guidelines from the CDC indicate that part of the cleaning strategy for environmental infection control should be to minimize contamination of the cleaning solution 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. Another source of contamination in the cleaning process is the cleaning cloth, especially if left soaking in dirty cleaning solution. 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.
The choice of wiping materials is also important, and many healthcare professionals may be surprised to learn that common systems such as using a cotton rag or cellulose-based wiper to apply bleach or quaternary amines to surfaces deliver less-than -ideal concentrations of disinfectants/sanitizers to the surface, according to two recent studies.
The studies evaluated cotton rags and disposable cellulose-based wipers used with an open bucket system against pre-saturated, disposable nonwoven wipers designed to be compatible with bleach used in a closed-bucket system. One studys results showed that cotton rags and cellulose-wipers in an open-bucket system rapidly depleted the active chloride ions present in bleach. However, the disposable nonwoven wiper used in the closed-bucket system kept it stable for a full 72-hour period.
In this study, the chloride ion release from the first cotton rage from the open bucket was 11 percent lower than the original bleach concentration. The chloride ion release from the first cellulose-based wiper was 13 percent lower than the original bleach disinfectant solution and dropped to 28 percent lower after 24 hours of use. In contrast, the initial chloride ion release for the disposable nonwoven wipers was only 3 percent to 5 percent lower than the original bleach concentration even after 72 hours of use.
A second study examined the effects of the same materials on the amount of active quaternary amines being released to the surface. This studys results showed a significant decline in the concentration of basic quaternary amines released when cotton rags or cellulose based wipers were used in the open bucket system compared with the disposable nonwoven wipers in the closed-bucket system:
Quat release for the first cotton rag was 53 percent lower than original for one quat solution and nearly 30 percent lower for another quat solution.
Quat release from the last cotton rag passed through the bucket was less than one percent of the original concentration.
Average quat release from cellulose-based wipers after eight hours was 21.5 percent of the original concentration.
Initial quat release for the disposable nonwoven wipers was only 16 percent lower for one quat solution and less than one percent lower for another quat solution.
The significant decline in the release of bleach and quaternary amine disinfectants when cotton rags and cellulose-based wipers were used in an open-bucket system implies that active disinfecting agents are not always applied to the surface in the ideal concentration to support optimum environmental disinfection of germ hot spots.
The use of treated nonwoven wipers with a fiber preparation designed to be compatible with disinfectant chemicals improves the delivery of the disinfectant chemical to the surface.
Selecting the appropriate wiper and system is critical to optimum disinfectant application. Wiping systems that sustain disinfectant concentrations over prolonged periods can improve disinfection protocol consistency in hospital germ hot zones.
Infection preventionists and environmental services professionals can look for further guidance on environmental surface cleaning and disinfecting in the Guidelines for Environmental Infection Control in Healthcare Facilities, which are recommendations of the CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC). The guidelines note that continued compliance with environmental infection control measures (including environmental surface cleaning and disinfecting) will decrease the risk of HAIs among patients.
How Infectious Pathogens Spread
Cross-contamination occurs when one person transmits contaminating bacteria or viruses to another person, either directly or through an inanimate object. Three factors are necessary to spread infection:
Causative agent The organisms capable of causing disease.
Mode of transmission The way the causative agent is transferred to the host.
Susceptible host Person lacking effective resistance to the causative agent.
Modes of transmission include:
Contact transmission, which can be both direct (involving body-surface-to-body-surface contact) or indirect (involving contact between a susceptible person with a contaminated object). Often, indirect contact is initiated when contaminated hands, that are not washed, contaminate an object or environmental surface, which in turn becomes a source of contamination.
Droplet transmission, when someone coughs, sneezes or talks and then transmits an infection to someone else via the conjunctivae or mucous membranes of the nose or mouth. While droplet contamination is generally considered to be a form of contact transmission, it can also contaminate the surrounding environment and lead to indirect contact transmission.
Airborne transmission, which occurs when respiratory airborne droplet nuclei are disseminated, usually by coughing, and then inhaled by a susceptible host.
Chris Kosobud is healthcare segment manager with Kimberly-Clark Professional.
1. CDC. Guidelines for Environmental Infection Control in Healthcare Facilities. June 2003.
2. Optimizing Infection Control. Kimberly Clark Professional Knowledge Connections On the Surface newsletter. Vol. 2.
3. Disinfection Tools. Kimberly Clark Professional Knowledge Connections On the Surface newsletter.