In the past 25 years there has been an increase in the number of reported infections in patients caused by methicillin-resistant Staphylococcus aureus (MRSA) (Panlilio, 1992). MRSA are gram-positive cocci, which are coagulase positive. They are resistant to antibiotics, such as methicillin, oxacillin, and nafcillin; aminoglycosides, such as tobramycin; and gentamicin, netilmicin, and many other antibiotics (Brumfitt, 1989).
Information related to placement and management strategies for patients infected with MRSA has come mainly from tertiary care centers, burn units, acute care facilities, and nursing homes affiliated with Veterans Administration hospitals (Strausbaugh, 1991; Strausbaugh, 1992). Generally, the aforementioned care settings have patients and /or environments with characteristics different from the majority of nursing homes in the United States. As infections with MRSA have become more prevalent in community hospitals throughout the country, the difficulty in controlling the spread within the community hospitals has mirrored that within the tertiary care centers.
Long-term care personnel have expressed concern that they also may experience difficulty in controlling the spread of MRSA within their facilities. Because community longterm nursing facilities have the option of refusing to admit patients whom they believe they are unprepared to manage, patients with positive cultures for MRSA frequently have been refused admission to nursing homes and have remained in acute care centers longer than necessary. Additionally, residents may also be refused readmittance to a long-term care facility once they are identified as being positive for MRSA.
This article will review the epidemiology of MRSA and identify the characteristics of nursing home residents and environments that make the care of MRSA residents difficult or simple. Approaches to patient placement and nursing management options also will be discussed. The management of MRSA is controversial; each facility must develop its own policies. Many state departments of health have written guidelines that may be of assistance.
EPIDEMIOLOGY OF MRSA
Agent of Disease
MRSA are gram-positive cocci, differing from methicillin-resistant species of S epidermidis (often referred to as "Staph epi" or "coagulase negative Staph") because they produce coagulase. S epidermidis is generally considered to be a microorganism of low virulence because it does not produce coagulase. MRSA is the same species as S aureus (sometimes referred to as "coagulase positive staph") but is distinguished from methicillin-sensitive S aureus by its resistance to methicillin and other antibiotics. MRSA has not been found to be an organism of greater virulence than methicillinsensitive strains of S aureus, but infections caused by MRSA are sometimes of greater concern because of the limited antibiotic treatment options (Boyce, 1992).
The primary reservoir for MRSA is persons who are colonized or infected with the microorganism. Although studies regarding the role of the environment as a reservoir for MRSA have been primarily limited to burn units, the environment is not believed to be an important factor in transmission of the organisms. Both infected and colonized residents may have cultures positive for S aureus, while only the infected resident will have signs and symptoms. In addition to laboratory reports, clinical assessment of the patient is necessary before the distinction can be made between colonization and infection. Colonization does not always precede infection; persons may be transiently colonized with no evidence of disease. Nursing home residents are colonized with a variety of microorganisms, including S aureus (Boyce, 1991a; Boyce, 1989). Distinguishing infection from colonization is important in guiding the physician's treatment decisions (Figure 1).
MRSA is transmitted by the contact route, that is, by direct or indirect contact between the reservoir and the susceptible host. An example of transmission via the contact route is the carriage of MRSA on unwashed hands of caregivers from patient to patient during direct care activities. Caregivers may also become nasal cartiers of MRSA; however, nasal carriage has rarely been linked to disease transmission (Boyce, 1992). Generally, MRSA is not transmitted by the airborne route.
Definitions for Infection and Colonization
Susceptible Host/Portal of Entry
As with other infectious diseases, a susceptible host is needed for an infection to occur. In acute care settings, the hosts most at risk for colonization or infection with MRSA are patients in intensive care units, burn patients, and patients with invasive devices (such as venous access devices) or surgical wounds (Brumfitt, 1989). In long-term care settings, the residents who seem to be at an increased risk are those with indwelling devices that breach the skin, such as intravascular catheters, tracheostomy or gastrostomy tubes, and indwelling urinary catheters; and those with decubitus ulcers (Boyce, 1992; Strasbaugh, 1991).
Checklist for the Containment of Body Substances of MRSA*Colonized/lnfected Residents
Caregivers may become transiently colonized with MRSA - as they do with other bacteria that cause infections in patients - by touching their faces or noses with contaminated gloves or unwashed hands. Generally, caregivers do not develop infections caused by MRSA.
NURSING HOME ENVIRONMENT
Long-term care facility staff may view the management of patients known to have an infectious disease as a problem because of the following constraints:
* Ehvironmentai Jimitations. Nursing homes have few private rooms, and handwashing sinks are often limited in number and inconvenient in location.
* Staffing issues. There is a low nurseto-patient ratio in long-term care, and nursing assistants provide the majority of "hands on" care (Jackson, 1989).
* Education and training limitations. In some states the majority of licensed staff are licensed practical nurses (LPNs), and infrequent inservice programs or variable attendance at framing sessions on infection prevention and control may limit understanding of general infection prevention measures.
* Resident characteristics. The majority of residents in long-term care are cognitively impaired, creating problems of poor comprehension and limited compliance with infection control measures.
* State regulations. Some state regulations mandate that nursing homes must refuse to admit residents whom they are unprepared to manage.
However, several factors present in long-term care facilities may suggest that residents infected or colonized with MRSA may be safely cared for in these settings (Figure 2). The following characteristics of longterm care facilities support the provision of safe care:
* Few invasive devices. Compared to the acute-care setting, residents in long-term care settings have relatively few invasive devices or other artificial portals of entry for microorganisms. Thus, the risk of transmission in this setting is reduced.
* Resident characteristics. Minimal contamination of the environment may occur, as many residents are dressed in street clothes.
* Patterns of nursing care. Although some residents may have invasive devices and nonintact skin, many residents do not. In the acute, intensive-care setting, nursing personnel have frequent contact with the multiple invasive devices in patients. Less contact occurs with devices and secretions that may be heavily laden with microorganisms in the long-term care setting.
CONSIDERATIONS FOR POLICY DEVELOPMENT
The isolation strategies for MRSAinfected or colonized patients remain a controversial issue (Bradley, 1991; Ribner, 1986). Therefore, to facilitate optimal care and transfer of residents between acute and long-term care facilities, the infection control committee in a long-term nursing facility may wish to develop policies regarding the admission, placement, and nursing management of such patients. The following factors should be considered in policy development: state regulations regarding the placement of infected patients; staffing, practice, and environmental constraints; resident characteristics; the prevalence of MRSA within the community; and the prevalence and history of MRSA within the nursing home.
As an example of staffing or practice constraints, facilities that do not perform intravenous (IV) therapy will probably not admit patients needing IV antibiotic therapy for an MRSA infection. The prevalence of MRSA within the community may be determined by communication with the infection control practitioners at other acute and long-term care settings. The prevalence of MRSA within the facility may be monitored by maintaining a line-listing of the patients who have had positive cultures for MRSA.
A caveat with this approach is the recognition that this microbiologybased monitoring approach only will identify colonized residents who are cultured and found to be positive; it will not identify those residents who are colonized and /or infected and not cultured Qackson 1992).
Historical information or linelisting of positive MRSA cultures not only may be useful to the infection control committee as a basis for policy development, but it may also be valuable to clinicians who use this information in decisions regarding antibiotic treatment.
Historical information regarding MRSA within the long-term care facility should include identification of nosocomial transmission of MRSA and patterns of antibiotic usage. For example, if nosocomial transmission within the nursing home has been documented, a policy with more rigorous control measures may be considered, especially when the increase includes serious nosocomial infections, such as bacteremia, lower respiratory infection, or deep wound infection caused by MRSA (Boyce, 1991b). An increase in the patterns of vancomycin usage may also be an indicator that control measures are needed.
If residents are rarely identified with MRSA and there are no data supporting nosocomial transmission, the precautions used for any resident may be adequate to contain MRSA (Kauffman, 1990). The rationale for using consistent patient care practices for all interactions with residents, rather than focusing on special measures or isolation strategies for the identified MRSA cases, is that unidentified colonized patients may continue to be reservoirs for this bacteria. However, some nursing facilities who have never had an MRSA-colonized or infected patient may believe they can avoid transmission problems if they elect to use special isolation measures.
The characteristics of the residents are extremely important in determining the risk for infections. Residents who have invasive devices, such as intravenous lines, large open wounds, and gastrostomies or tracheostomies, are at an increased risk of colonization or infection with many pathogens - including MRSA. Conversely, residents who are infected or colonized with MRSA, who have intact skin (eg, no draining lesions, TVs, or tracheostomies), and who have their body secretions and excretions contained, present little risk of transmission of MRSA to other residents with intact skin.
Residents with positive cultures for MRSA who have a wound also may present little or no risk to their roommate(s) if all wound drainage is contained, and if handwashing and appropriate barrier techniques are used by caregivers. The roommate(s) then may not be at increased risk for colonization or infection even if they have nonintact skin or invasive devices. The site of the infection - and the specific characteristics and needs of both the infected or colonized patient and the potential roommate(s) - must be considered when making decisions regarding patient placement (Figure 3).
APPROACHES TO MANAGEMENT OF MRSA
Use of Vancomycin
Although MRSA is believed to be no more virulent than methicillinsensitive S aureus, vigorous efforts often are made to control it because of the potential difficulties associated with the antibiotic treatments and the potential for the increased use of vancomycin. The increased use of vancomycin has the potential to lead to the emergence of vancomycin-resistant microorganisms (Boyce, 1991b). Because of the treatment challenges and tiie potential difficulties in eradicating MRSA once it is established within a facility, the control efforts are often focused on the barrier or isolation techniques. These techniques contain the microorganism and prevent transmission to other susceptible hosts.
Checklist for Selecting MRSA Infected/Colonized Resident Roommates
Efforts to prevent the transmission of MRSA in health care facilities have ranged from placing patients positive for MRSA in strict isolation, to the use of barrier techniques appropriate for all patients, such as universal precautions (Centers for Disease Control [CDC], 1987; Ribner, 1986;) or body substance isolation (Lynch, 1987; Lynch, 1990). Varying levels of success in controlling the spread of MRSA are reported with these different approaches to isolation.
Universal precautions, as described by the CDC (1988), were developed to prevent the transmission of bloodborne pathogens such as hepatitis B and the human immunodeficiency virus. Universal precautions were not designed to prevent the transmission of pathogens such as MRSA. The equipment and procedures used to establish a barrier between the caregiver and the resident infected or colonized with MRSA has been tried in many different combinations (Boyce, 1991b; Cohen, 1991). There is a lack of agreement upon which method is the single best way to contain MRSA. The necessity for, and success of, special MRSA control measures remains controversial.
In addition to the Universal Precautions outlined by the CDC in 1988, some facilities use strict isolation techniques, which include the use of gowns, gloves, and face masks for all contact with the resident or the resident's environment. Other facilities may use gown, gloves, and mask only for contact with the culture-positive site. The rationale for the use of the mask in strict isolation, or whenever contact is anticipated with the culture-positive site. is the prevention of the rare - but possible - transmission by droplets. Droplets may be spread by the resident on a ventilator (who is sputumfor MRSA) or by an unwashed hand or contaminated glove into contact with the nose and face of the caregiver (Bennett, 1992). For facilities using contact isolation as defined by the CDC in 1983 (Garner, 1983), gloves, and impervious aprons or gowns, will be used whenever direct contact with the resident - or equipment contaminated the resident - is anticipated.
Body substance isolation, used by some facilities, includes the use of barriers such as aprons/gowns, gloves, and masks whenever contact is anticipated with the moist body substances of residents (excluding tears and sweat), regardless of the patient's diagnosis (Jackson, 1987). The finding that nursing home residents are colowith a variety of microorganisms, including MRSA, supports the consistent application of handwashing and barrier techniques for all patients, not just those with positive cultures.
Handwashing and the use of barriers such as gloves and aprons/ gowns - when contact is anticipated with potentially contaminated material - is not only important for the of MRSA, but also for other pathogens. It is essential that gloves used for patient care be reafter each patient and not worn from patient to patient. Although the practice of wearing gloves from resident to resident may offer some protection to the caregiver, it is unsafe for the residents, it provides a mechanism for the transmission of microorganisms.
Measures for Outbreaks
In outbreak situations, the facility's infection control committee may recommend more extensive surveillance and control measures. These measures may include surveillance cultures of nares, wounds, and perineums/rectums of residents on a specific ward, or residents with indwelling catheters and/or gastrostomy/ tracheostomy tubes (Walsh, 1987). Consideration may be given to cohorting or placing residents with positive cultures in a specific ward or unit (Kauffman, 1990; Storch, 1987). Strategies for the control of an unacceptable incidence of nosocomial MRSA infections should be developed by the facility's infection control committee. These strategies should include the factors incorporated into decisions related to nonoutbreak MRSA-policy development.
Education regarding the transmission of microorganisms and the caregiver's role in prevention is essential for every nursing facility. Indications and procedures for handwashing are an integral part of staff education. The appropriate use of gloves, gowns, and other barriers are also important in providing care that is safe for the staff as well as the residents. Staff fears regarding MRSA may be addressed and reduced through an education that includes the rationale behind the use of barrier devices and resident placement strategies.
Interfacility communication is essential for hospital and nursing home staff to plan and manage the care of infected or colonized residents. It is through open communication that residents and potential roommates can be assessed, and decisions made regarding room or unit placement options (Conley, 1989).
Determining the risk of microorganism transmission from residents infected with MRSA (or other pathogens) by the containment of body fluids - along with assessing the susceptibilities of potential roommates - is a scientific way to determine patient placement. Incorporating information about the epidemiology of MRSA, the characteristics of residents, and the limitations of staff or physical plant into a facility-specific MRSA policy should optimize the opportunity for infected persons to receive nursing home care - without jeopardizing other residents.
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Definitions for Infection and Colonization
Checklist for the Containment of Body Substances of MRSA*Colonized/lnfected Residents
Checklist for Selecting MRSA Infected/Colonized Resident Roommates