Infection Control in Long-Term Care Facilities

Transcription

1 752 SPECIAL SECTION: HEALTHCARE EPIDEMIOLOGY Robert A. Weinstein, Section Editor Infection Control in Long-Term Care Facilities Lindsay E. Nicolle Department of Internal Medicine, University of Manitoba, Health Sciences Centre, St. Boniface Hospital, Winnipeg, Manitoba, Canada Infections are common in long-term care facilities. The most frequent endemic infections are urinary infection, respiratory infection, and skin and soft tissue infections. Outbreaks also occur frequently, and some facilities have a high prevalence of colonization of residents with antimicrobial-resistant organisms. Our understanding of infections and the development of infection-control programs for long-term care facilities have progressed greatly over the past 15 years. Whereas the occurrence of infections has been described and specific guidelines for infection-control programs in long-term care facilities have been developed, there is still limited evaluation of the effectiveness of programs or specific interventions to support prioritization of infection-control resources. In addition, the spectrum of patients and care delivered in longterm care facilities continues to evolve. Increasingly, chronic care patients, including those requiring chronic respirator therapy, dialysis, or percutaneous feeding tubes, are cared for in these facilities. Our understanding of prevention of infection in these patients remains limited. Important questions include what interventions may prevent endemic infections, what are the most effective means to identify outbreaks early, and what interventions may minimize the prevalence of antimicrobial-resistant organisms. Programs to optimize antimicrobial use need to be developed. Thus, although progress in understanding and practice has been made, important questions remain. Long-term care facilities are a heterogenous group of organizations that provide care to a broad spectrum of persons. Patients range from pediatric to geriatric and may be admitted for psychiatric as well as medical care. Institutionalization for the patient may be permanent or for a period of rehabilitation with a view to subsequent discharge to the community or another facility. The majority of long-term care facilities, however, provide care for elderly persons who reside permanently in these facilities. This commentary is relevant to these facilities and the elderly resident. Infections are common among residents in long-term care facilities [1], with a frequency comparable to rates observed in acute care facilities (table 1). Infections in these settings can be considered within the framework of endemic infections, outbreaks, and antimicrobial resistance. Respiratory tract infections, urinary tract infections, and skin and soft tissue infections are the most Received 2 May 2000; revised 21 July 2000; electronically published 21 September Publication of the Special Section on Healthcare Epidemiology has been made possible by an educational grant from Pfizer Pharmaceuticals Group, Pfizer, Inc. Reprints or correspondence: Dr. Lindsay E. Nicolle, Dept. of Internal Medicine, University of Manitoba Health Sciences Centre, GC Sherbrook St., Winnipeg, Canada R3A 1R9 (lnicolle@hsc.mb.ca). Clinical Infectious Diseases 2000;31: by the Infectious Diseases Society of America. All rights reserved /2000/ $03.00 frequent endemic infections [1]. Outbreaks are common, with influenza A virus and gastrointestinal infections the most frequent and severe [1, 2]. Residents of some long-term care facilities have a high frequency of colonization with antimicrobial-resistant organisms, including methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, penicillin-resistant pneumococci, extended spectrum b-lactamase producing gram-negative organisms, and quinolone-resistant gram-negative organisms [1, 3, 4]. The profile of patients in some facilities is changing in concert with changes in the rest of the health care delivery system. There is an increase in the level of care required for residents, because of earlier discharge from acute care hospitals and an increasing use of invasive devices. Chronic indwelling urethral catheters have always been common, used in 5% 10% of residents [5]. Now, there frequently are patients with tracheostomies who are undergoing long-term respirator therapy, patients receiving hemodialysis or peritoneal dialysis, patients with central vascular catheters, and patients receiving nutritional support via percutaneous feeding tubes. There is little information to date describing the occurrence of and risk factors for infection specifically in patients undergoing these therapies in long-term care facilities. Issues in Infection Prevention in Long-Term Care There are several considerations in approaching prevention of infections in the long-term care facility. Patients are institution-

2 CID 2000;31 (September) Infection Control in Long-Term Care 753 Table 1. facilities. Frequency of infections reported from long-term care Infection Prevalence, % Incidence/1000 patient-days All infections Respiratory Urinary Skin/soft tissue Gastrointestinal NOTE. Adapted from [1]. alized because they have significant chronic comorbid illnesses and impaired functional status. In general, the extent of comorbidity and level of functional impairment are also associated with the risk of infection or colonization with resistant organisms [1, 6, 7]. Because the variables that determine institutionalization are the same factors that promote infection, there may be limited opportunities for prevention of infection, especially endemic infection, in residents of these facilities [1]. Most elderly residents of long-term care facilities have the long-term care facility as their permanent domicile. The intensity of efforts to prevent transmission of infection between residents who are in their home environment requires a balanced approach. Isolation or limitations in activity and mobility cannot be justified unless there is evidence that a given resident is a risk to others and that barriers that may restrict socialization will decrease that risk [3]. Clinical and laboratory assessment are often limited in longterm care facilities, and diagnostic uncertainty in identification of infection in residents is frequent [1, 5, 8]. It may be difficult or impossible to determine whether an infection is present or, if an infection is present, the site and specific etiologic agent. Clinical presentations differ from those in younger, less-impaired populations, because of chronic symptoms of comorbid illness, impaired communication, or aging-associated blunting of the temperature response. Diagnostic tests may not be obtained, because patients cannot cooperate (e.g., sputum collection) or because of lack of accessibility (e.g., on-site chest radiography). When microbiological tests are obtained, the interpretation of positive results is frequently problematic. For instance, 20% 50% of all long-term care facility residents are bacteriuric at any time [6], so a positive urine culture has a low positive predictive value to diagnose symptomatic urinary infection [9]. About 40% of residents have oropharyngeal colonization with gram-negative organisms, compromising interpretation of sputum cultures [1], and pressure ulcers and other chronic skin lesions are uniformly colonized, frequently with potential pathogens [10]. Finally, measurements of outcomes and goals of interventions may differ from those in other populations (table 2). For example, for permanent residents, length of stay is not a useful measure of effectiveness of an intervention but maintenance of functional status likely is. Mortality will sometimes be a humane outcome, such as in the severely functionally impaired demented person who develops pneumonia [8]. Thus, infection prevention in the long-term care facility must be viewed within a framework of baseline medical and functional compromise of patients, diagnostic imprecision, and outcome measures relevant to this population. Infection-Control Programs The infection-control program is the organizational structure within which infection prevention is standardized and implemented. Over the past 2 decades, there has been substantial progress in the implementation and practice of infection-control programs within long-term care facilities [11, 12]. This was driven in part by regulatory requirements [11] and in part by the increasing appreciation of the frequency of infections in these facilities. Evidenced-based guidelines for recommendations for the structure and components of an infection-control program in long-term care facilities have been published as a Society for Healthcare Epidemiology of America/American Practitioners of Infection Control (SHEA/APIC) position paper [13]. Consensus definitions for surveillance of infection in long-term care facilities have been developed and are widely used [14]. Guidelines identifying minimal essential criteria for infection control in health care settings outside the acute care hospital, including long-term care facilities, conclude that the fundamental components of surveillance, policy development, employee health, and education are similar for long-term care facilities and for other health care delivery programs [15]. There are, however, several differences characterizinginfectioncontrol programs in acute and long-term care facilities [13]. In general, long-term care facilities have fewer resources in personnel, expertise, and diagnostic or support services. Persons responsible for infection control usually have multiple other responsibilities and may not have a level of training equivalent to that of practitioners in acute care facilities. Access to computers and secretarial support is limited. On-site laboratory or diagnostic imaging is infrequent, and diagnostic microbiological testing may not be available. There is less access to medical expertise for assessing and monitoring unstable patients because physician reimbursement practices usually restrict the frequency of physician attendance for patients in these facilities. The medical record is less complete and may not be useful for identification of infection. Finally, a major limitation for infection-control programs in long-term care facilities is the limited evidence to support the effectiveness of such programs or individual components of programs [13]. Although the Study on the Efficacy of Nosocomial Infection Control (SENIC) study has documented the effective- Table 2. Goals of infection prevention among residents of longterm care facilities. Decrease morbidity/mortality attributable to infections in residents Prevent and control outbreaks of infection Prevent acquisition of infection by staff members Limit costs of care attributable to infections Limit antimicrobial use Maintain resident functional status Maintain optimal social environment for residents

3 754 Nicolle CID 2000;31 (September) ness of infection-control programs in acute care facilities, similar evidence of program benefits to support commitment of resources in the long-term care facility is not available. In fact, a recent study was unable to show a decrease in endemic infection rates in nursing homes in which a program stressing hand washing, infection-control education, and environmental cleaning was undertaken, compared with rates in nursing homes used as controls [16]. Thus, there is an important need for further evaluation of infection-control programs in these settings, to ensure optimal effectiveness and cost-efficiency. Endemic Infections As mentioned earlier, the major determinants of endemic infection in residents of long-term care facilities are the associated comorbid conditions and impairment of functional status. For instance, asymptomatic bacteriuria is highly associated with the presence of bowel and bladder incontinence and dementia [6]. Although it might be feasible to decrease the occurrence of infection by limiting use of condom catheters or chronic indwelling catheters, these devices are appropriate and useful in the care of some patients [5]. Pneumonia, the only infection contributing significantly to mortality [1], is associated with poor or deteriorating health status, chronic obstructive lung disease, tracheostomy, and aspiration [7]. In general, these characteristics are not modifiable, and no studies have yet documented that alternate feeding strategies decrease the frequency or morbidity of pneumonia. Whereas pneumococcal vaccination is recommended for all nursing home residents, the impact of this intervention in altering overall morbidity and mortality in the institutionalized population is still unclear. Colonization and infection with antimicrobial-resistant organisms such as methicillin-resistant S. aureus is most common in the most highly functionally impaired residents [1, 3, 17]. Infected pressure ulcers can be prevented by optimal nursing care. However, most residents of long-term care facilities who have pressure ulcers acquire these in other facilities before transfer to long-term care [10]. Thus, many questions remain about prevention strategies for endemic infection, and the feasibility of prevention of most of these infections is uncertain. Several randomized comparative clinical trials relevant to specific aspects of care of residents of long-term care facilities have been reported [18 20]. These not only provide information about the specific intervention evaluated but also serve as examples of the feasibility and usefulness of such trials. The role of malnutrition in infection is not well studied in this population, although it is frequently thought that these patients are malnourished and therefore at risk for infection. In one study, a randomized trial of supplementation with vitamin A did not decrease the frequency of infection in a group of residents in a long-term care facility [18]. Routine changes of gastric or jejunal feeding tubes did not decrease the occurrence of infection, compared with changes as circumstances required. In fact, routine changes were associated with an increased frequency of the feeding tube falling out [19]. Finally, residents with neurogenic bladders and voiding managed by intermittent catheterization had a similar frequency of urinary infection whether a clean or sterile catheterization technique was used [20]. Thus, observations from these studies have been uniformly negative with respect to effectiveness of the intervention in preventing endemic infection. Outbreaks Outbreaks of infection are common in long-term care facilities, and a wide variety have been reported (table 3) [1]. The most important organism, in terms of frequency and morbidity, is influenza A virus; gastrointestinal infections caused by Escherichia coli O157, Salmonella species, and caliciviruses and skin infestations with scabies are other important and relatively common problems. Outbreaks with 11 pathogen, including dual respiratory viruses, influenza A virus and a bacterial pathogen, and dual gastrointestinal pathogens, may occur. Effective outbreak management requires prior planning for an outbreak event, with issues unique to the most common and important pathogens specifically addressed [13, 15]. Effective Table 3. Organisms reported to cause outbreaks in long-term care facilities for the elderly. Type of organism Viruses Bacteria Parasites Ectoparasites Organism Influenza A virus Influenza B virus Parainfluenza virus Respiratory syncytial virus Adenovirus Rhinovirus Coronavirus Astrovirus Rotavirus Calicivirus Hepatitis B virus Haemophilus influenzae type b and nontypeable Legionella pneumophila Legionella sainthelense Streptococcus pneumoniae Bordetella pertussis Mycobacterium tuberculosis Salmonella species Shigella species Escherichia coli O157 Campylobacter jejuni Aeromonas hydrophila Bacillus cereus Clostridium perfringens Clostridium difficile Staphylococcus aureus (enterotoxin producing) Methicillin-resistant S. aureus Group A streptococci Extended-spectrum b-lactamase producing gram-negative organisms Vancomycin-resistant enterococci Giardia lamblia Entamoeba histolytica Cryptosporidium species Sarcoptes scabies hominis

4 CID 2000;31 (September) Infection Control in Long-Term Care 755 implementation of control programs should limit the occurrence and extent of outbreaks. An important element is ongoing surveillance to support early identification of outbreaks. Because limited laboratory testing is frequently the norm, decision points identifying clinical situations in which laboratory testing must be obtained are essential. These will vary with the institutional characteristics and resources but should include prompt identification of potential clusters of influenza and other respiratory illness, gastroenteritis, and skin infection. Restrictions in patient activity and visitor restrictions must also be addressed, and considerations relevant to resources, leadership, and authority must be delineated. Appropriate liaison with public health personnel and laboratories is essential. Outbreaks of influenza A virus may occur on a yearly basis and are associated with mortality rates as high as 10% 30% [2]. All long-term care facilities must have ongoing programs to minimize the impact of influenza epidemics. Key features of these programs include yearly influenza vaccination for both patients and staff, clinical and laboratory surveillance for early identification of potential influenza cases, and guidelines for provision of prophylaxis or treatment of cases once influenza is recognized in the facility. Both E. coli O157 and Salmonella species outbreaks have been associated with excess mortality in nursing home residents [1]. In one reported outbreak caused by E. coli O157:H7, the mortality of infected residents was 35%, and 120% developed hemolytic-uremic syndrome. The impact of an outbreak of this magnitude on a facility is substantial. Gastrointestinal outbreaks can be prevented with appropriate food-handling practices and appropriate hand washing and glove use in patient care, particularly with handling contaminated linen and patient excreta. Outbreaks caused by caliciviruses, such as the Norwalk agent, may cause disease in a high proportion of both patients and staff but have been associated with low mortality. Effective interventions to prevent or limit calicivirus outbreaks are not well established, because the explosive nature suggests transmission by routes other than contact. Policies must identify criteria for specimens from residents with diarrhea or gastroenteritis to be forwarded to the laboratory for stool culture or electron microscopy, so that outbreaks are rapidly identified and interventions promptly initiated. Scabies outbreaks have repeatedly occurred in long-term care facilities [1]. A common theme in these outbreaks is failure of early recognition of the index case as scabies. Both staff members and other residents subsequently become infected. Thus, each facility needs a policy specific for scabies that addresses the diagnosis of rashes, rapid treatment of infected residents, and management of contaminated linen. Antimicrobial Resistance A high rate of colonization with antimicrobial-resistant organisms has been reported in many nursing homes. This is not, however, a universal observation, and some nursing homes have not yet experienced this problem. The epidemiology of methicillin-resistant S. aureus and vancomycin-resistant enterococci have been the most completely studied [3, 4]. Patients generally acquire methicillin-resistant S. aureus or vancomycin-resistant enterococci in the acute care facility and remain colonized for extended periods once transferred to a long-term care facility [21, 22]. Transmission from resident to resident within the long-term care facility is infrequent, although occasional outbreaks have been described. In the case of methicillin-resistant S. aureus and vancomycin-resistant enterococci, the prevalence of colonization may be high but infection is uncommon, and excess morbidity directly attributable to these resistant organisms has not been documented. Although methicillin-resistant S. aureus and vancomycin-resistant enterococci frequently contaminate the immediate patient environment (e.g., bed rails and tables), environmental cultures from common patient areas, such as the dining area, are seldom positive [21, 23]. The use of intensive barrier and isolation precautions has not been shown to be more beneficial than gloving or hand washing in limiting the frequency of colonization or infection [24, 25]. In selected circumstances, such as a patient with extensive skin lesions colonized with methicillin-resistant S. aureus or incontinence of stool and diarrhea with vancomycin-resistant enterococci, stricter precautions may be necessary [3]. Most efforts at decolonization of patients infected by methicillin-resistant S. aureus that make use of antimicrobial therapy have been ineffective and are not associated with a decreased occurrence of infection in a facility [3]. Thus, recommendations for general screening or intense isolation for residents colonized with these resistant organisms in the long-term care facility cannot be justified on the basis of current evidence. There is also no evidence to support nonadmission of residents to the long-term care facility on the basis of being colonized or infected by resistant organisms. In fact, available evidence is consistent with prevention of acquisition in acute care facilities being the most effective strategy to decrease the prevalence of colonization by methicillin-resistant S. aureus and vancomycin-resistant enterococci in the long-term care facility. Much less is known about colonization by penicillin-resistant pneumococci or extended-spectrum b-lactamase producing gram-negative organisms in residents of long-term care facilities. Ciprofloxacin-resistant gram-negative organisms are reported to be increasing in frequency in some facilities. In this case, the intensity of use of quinolone antimicrobials in the long-term care facility appears to be an important variable [26]. Antimicrobial use is an important issue relevant to antimicrobial resistance in long-term care facilities. There is intense use of antimicrobials in these facilities and, as in any other population, a substantial proportion of this is inappropriate use [8]. Many factors drive this inappropriate use. The most important is diagnostic uncertainty, which means that most antibiotic use is empirical. Recommendations for improving

5 756 Nicolle CID 2000;31 (September) antimicrobial use have included development of a formulary and continuing review of antimicrobial use and prevalence of antimicrobial resistance in cultures obtained from patients with suspected infection [13]. However, to address the large problem of intense antimicrobial use in long-term care facilities, relevant clinical trials that define the utility of diagnostic testing as well as outcomes with different empirical therapies and, in fact, with no antimicrobial therapy are needed. Although recommendations for ongoing monitoring of antimicrobial use in long-term care facilities have been made, the extent to which these have been implemented and their utility are currently unknown. The Future The spectrum of care delivered to patients in long-term care facilities is changing, as it is throughout the health care system. Some facilities are moving toward a patient mix that may be more consistent with acute care, with patients with multiple invasive devices, including those on respirators, undergoing dialysis, or with central catheters in place. Other facilities may provide a domicile but little direct care of relatively well elderly residents. Facilities will have a different experience with infections and, likely, will require different approaches to infection control depending on the patient mix. The different risks of infection and appropriate approaches to infection prevention need to be described for the full spectrum of long-term care facilities. Over the next decade, further evaluation of the utility of infection-control programs, particularly for endemic infections, needs to be achieved. In addition, a critical assessment of how to ensure optimal antimicrobial use in these populations is necessary. Reviewing the advances in knowledge and practice in infection control in long-term care facilities over the last 15 years gives reason for optimism. Many complex, interesting, and important questions remain, however. The changing demographics in developed countries with increasing numbers of elderly residents warrants continued resources directed toward resolving problems of infection control in long-term care facilities. The goal is to optimize care of our elderly institutionalized population and respond effectively to the evolution of health care in long-term care facilities. References 1. Nicolle LE, Garibaldi R, Strausbaugh LJ. Infections and antibiotic resistance in nursing homes. Clin Microbiol Rev 1996;9: Bradley SF, Long Term Care Committee of the Society for Health Care Epidemiology of America. Prevention of influenza in long term care facilities. Infect Control Hosp Epidemiol 1999;20: Strausbaugh LJ, Crossley KB, Nurse BA, Thrupp LD, SHEA Long Term Care Committee. 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