Nosoeotnial infections are those that are acquired m hospitals or institutions. Many conditions commonly experienced by the elderly predispose them to infecttion, including immune system changes, congestive heart failure, diabetes: mellitus, emphysema, and cancer. Changes in the immune system that are associated with aging are listed in the Table.
Immobility, dehydration, malnutrition, and impaired mental status also predispose to infectious -disease...1' Malnutrition, specifically deficiencies In vitamin Bg and folate, is second only to the changes related to aging as a canse of impaired imrnnaity in adults^23 The incidence of nosocomial Infection will likely increase because of the growing number of elderly requiring long-term care, and the. severity of illness in residents of long-term care facilities (LTCFs) related to earlier hospital -to-LTCF transfer. Because of these problems, gerontological nurses must be particularly alert to the dangers of nosocomial infections as described in this "article.
One study of 1,220 nosocomial infections over a 2 -year period reported that 64% of the victims were over age 60, although this population represented only 23% of the total number of hospitalized patients.4 Another recent report noted a nosocomial infection rate of 3.86 per 1000 patient days in an intermediate care facility for veterans.5 Saviteer, Samsa, and Rutala found that the daily infection rates were 0.59% in patients over age 60 and 0.40% in younger persons.6 They also recorded the daily incidence of urinary tract infections, respiratory infections, and septicemias, which increased in the elderly, with risk ratios of 2.78, 2.07, and 1 .36, respectively. Elderly patients developed significantly more nosocomial infections for each day after the seventh day of hospitalization, suggesting the deleterious effects of immobility in this population.
Reservoirs for infectious organisms are numerous in LTCFs and hospitals. Most infections result from the elderly person's own flora of the perineum, skin, or nasopharynx. Visitors or staff may also carry agents causing infection in elders, such as influenza and upper respiratory viruses. Cross infection through contact is also a cause of nosocornial infection. Food and water may provide vehicle transmission of infection, and the air may disseminate droplets containing infectious agents. In LTCFs, transmission of infection is accentuated by defective handwashing practices and isolation facilities. Education about the transmission of infectious disease is frequently neglected, or addressed only in yearly inservice presentations. The Figure depicts the process of nosocomial infections.
Smith reports that epidemics occur frequently in LTCFs.7 Upper respiratory tract infections, diarrhea, conjunctivitis, and antibiotic-resistant bacteriuria have been noted most frequently.8 This article briefly examines the most common nosocomial infections, those of the respiratory tract, gastrointestinal and genitourinary tract, and the integumentary system.
The increase in nosocomial pneumonias is three times greater for persons in their 70s and 80s than for persons in their 20s.2·3 Pneumonia, described a century ago by Sir William Osier as the "special enemy of old age," has resulted in higher mortality rates in the elderly than in younger adults.9 The most common cause of communityacquired pneumonia is Streptococcus pneumoniae, which is identified as a nosocomial pathogen in elderly patients. In a 5-year study of 56 cases of elderly persons with pneumococcal bacteremia, 41% were found to be nosocomial and 59% community-acquired. Mortality rates for pneumonia acquired in the LTCF are significantly higher than pneumonia acquired in the community.1 In nursing homes and hospitals, gram-negative enteric bacilli, Klebsiella pneumoniae in particular, causes this infection. The elderly are especially susceptible to pneumonia from Legionella, Branhamella catarrhalis, group B ß-hemolytic streptococci, and mixed aerobic bacteria.10 And yet, pneumonias may be difficult to detect because of atypical presentations. Pneumonia should be suspected in the elderly if the respiration rate is more than 26 breaths per minute or unexplained tachycardia occurs.3 In 15% to 20% of elderly patients with pneumonia, no symptoms such as fever, cough, or pain are present, with confusion and coma due to anoxia being the only symptoms.2 Aspiration pneumonia is also common in LTCFs. Gram-negative bacteria, frequently found in the mouth and from dental caries or gingivitis, may cause pneumonitis when aspirated.1
THE EFFECT OF AGE ON THE IMMUNE SYSTEM3
Hemophilus influenzae is becoming increasingly common in the elderly. Twenty-five to sixty percent of institutionalized elderly contract influenza with fatality rates of approximately 10%. n The elderly, especially those who are institutionalized, experience significantly more viral upper respiratory diseases than younger persons.
Tuberculosis (TB) has also been on the increase among the elderly. In 1953, 13.8% of persons with TB were over age 65, but in 1979, that figure rose to 28.6%, while infection rates in the general population have risen only from 8.7% to 11.2% over the same period.12 One study reports that TB is an important risk for nursing home patients and that much care should be taken to detect and treat new infections before the disease has spread.13
Urinary tract infections and bacteremias are five times more frequent in elderly persons in their 70s and 80s than for those between ages 20 and 40, with asymptomatic bacteriuria being extremely common.2 This can be caused by prostatic hypertrophy in men, perineal soiling in women, bladder dysfunction, loss of hormonedependent protection in women, fecal incontinence, and loss of bactericidal prostatic secretions in men, as well as genitourinary instrumentation. Treatment should always be sought for infections that have symptoms. However, bacteria found in urine samples of institutionalized elderly are generally more resistant to oral antibiotics than the corresponding bacteria found in community-dwelling elders.14,15
DEVELOPMENT OF NOSOCOMIAL INFECTION3
Foley catheters are often the culprit in urinary tract infections in the elderly. It is important to adhere to basic principles of catheter care when a catheter is in place, and also to use catheters only as a last resort to avoid urinary retention and skin breakdown. Urinary tract infections, even without symptoms, can cause bacteremia in the elderly, especially with gram-negative organisms.16 Bacteremia is a potentially fatal risk, and gerontological nurses must be diligent to prevent its development by astute observation of the elder's physical condition and assessment of any symptoms. A significant challenge is that die majority of geriatric patients with urinary tract infections have no symptoms.3
Outbreaks of diarrhea occurring in LTCFs can usually be blamed on viral infections, bacteria, or preformed toxins.3 The pathogenic organisms implicated in viral diarrhea tend to be rotavirus and parvovirus. Viral diarrhea is exhibited by an abrupt onset and lasts from 1 to 5 days. Abdominal cramping, malaise, anorexia, and nonbloody watery stools are seen. The danger of dehydration, especially in debilitated elderly clients, is paramount.3
Causative organisms in bacterial diarrhea include shigellosis, salmonellosis, or Campylobacter diarrhea. The onset of bacterial diarrhea tends to be less abrupt, with accompanying fever, bloody stools, and tenesmus (ineffective straining at stool).3
Toxin-induced diarrhea frequently follows the use of certain antibiotics (erythromycin, clindamycin, tetracycline, and occasionally ampicillin) causing the overgrowth of Clostridium difficile. Staphylococcus aureus also produces an enterotoxin, resulting in diarrhea.3
Careful infection control measures, assessing the incidence and symptoms of diarrhea, are imperative. Handwashing by all persons who handle food is essential in all settings, but particularly in LTCFs. Gerontological nurses must also be alert to the gastrointestinal consequences of antibiotic use and take measures to minimize secondary infections, including diarrhea, by reporting occurrences and instituting proper treatment. Treatment can include antidiarrheal medications, changes in diet texture, and pushing fluid intake.
The incidence of nosocomial wound infections is twice as great for individuals over age 70 as for those between ages 20 and 40.2 Infection of pressure ulcers is also common, which can cause complications of sepsis, osteomyelitis, or cellulitis.16 Cases of tetanus and amyloidosis have also been reported.16 Not only do pressure sores represent enormous health-care costs and patient discomfort, but they can increase mortality from sepsis as well.2
Other infections of the integumentary system include conjunctivitis, scabies, herpes zoster, herpes simplex, and cellulitis. The incidence of these diseases vary from institution to institution and the exact frequency is unknown.
IMPLICATIONS FOR PRACTICE
A number of geographically diverse studies have shown that LTCFs have regular infection control meetings, but systematic surveillance for infections and the conduct of regular inservice programs on infection control were lacking.8,17"19 Most facilities have policies in place, but the implementation of employee and resident health programs and isolation procedures is inconsistent.8·17-19
With the Omnibus Budget Reconciliation Act (OBRA '87) regulations in effect in October 1990, renewed interest in infection control in the elderly has emerged in LTCFs. OBRA '87 regulations require mat all nursing facilities institute infection control programs either alone or in conjunction with quality assurance programs. The functions of the infection control program include the investigation, control, and prevention of infections in the facility; deciding what procedures, such as isolation, should be applied to an individual resident; and maintaining a record of incidents and corrective actions related to infection. Wim infection control programs, emphasis is placed on the development of policies and procedures geared to the prevention of infection and its spread, as well as surveillance of infection and staff education. It is anticipated that a wellfunctioning infection control program will significantly reduce the incidence of nosocomial infections in LTCFs.
In the surveillance of infections, information is collected to plan control mechanisms. If infections are noted early, epidemics may be thwarted and therapeutic interventions instituted. The National Nosocomial Infections Surveillance (NNIS) system is used in hospitals for infection control,20 although there are currently no such standards for infections in LTCFs. NNIS definitions depend heavily on laboratory data and medical record review; however, in LTCFs these services are often unavailable and are sparsely documented, especially in physician notes. Modified criteria specific for LTCFs have been suggested,7·21 but to date, clear-cut criteria have not been widely accepted for the diagnosis of nosocomial infections in LTCFs.
With the advent of formal infection control programs and associated quality assurance activities, effective surveillance of infections can occur by monitoring the incidence of elevated temperatures, results of laboratory cultures, and antibiotic use. Although these data are not as sophisticated as the information routinely provided in acute care settings, they can be useful in pinpointing the incidence and prevalence of infections.
The requirement that facilities conduct an infection control inservice has been in effect, but many facilities experience great turnover in personnel, especially nursing assistants. This makes it difficult to deliver an effective infection control educational program. Ongoing educational programs on a formal and informal basis are highly recommended. Improved infection control activities have been shown to be a direct result of an effective, coordinated educational program involving infection control.22 Specifically, these programs have increased written definitions of infection, employee influenza vaccine usage, and resident influenza vaccine usage. Educational programs in LTCFs must include content on effective handwashing, which is the single most important component of an infection control program. As noted earlier, education in this area should be done frequently on an informal basis, and reinforced formally in orientation programs.
To be effective, infection control must include appropriate policies and procedures. Isolation procedures must be clear and up-to-date as well as easily implemented. Treatment procedures must be current. For example, are Foley catheters being irrigated routinely? This treatment is outmoded and has been found to cause infection, yet many LTCFs continue to follow this practice. The use of alcohol as a disinfectant has been found to be ineffective in killing many microorganisms, yet facilities continue to use alcohol in the absence of more current infection control policies and procedures.
Employee health programs are also important in LTCFs. OBRA '87 regulations mandate that all employees be free of infectious disease. Therefore, physicals, including a tuberculous screen, should be required for all new employees and at least every 4 years thereafter. The primary purpose of the physical examination is to determine that the employee is free of communicable disease. It is also important to enforce regulations that prohibit employees from working who have an active infection, such as the flu, open wounds on the skin, or lesions such as burns and herpes simplex. Because of staffing shortages, it is tempting for management to permit employees to work while infectious, but the longterm consequences can be disastrous.
Employee health programs should also include vaccination programs for influenza. Most cases of influenza are brought into the facility by employees, so it is logical that it would be cost effective for administration to provide vaccinations for employees free of charge. Many health-care employers also offer hepatitis vaccines for nurses to prevent the spread of hepatitis B. Again, when one compares the cost of the consequences of infection with hepatitis B, the cost of offering vaccines to employees is minimal.
Health programs for residents are also important. Residents of LTCFs must have physicals upon admission and periodically thereafter to certify that they are free of infectious disease, including tuberculosis. Vaccination programs that include yearly influenza vaccinations and lifetime pneumonia immunity are invaluable. The pneumococcal vaccine is the most important preventive measure for pneumonia. Frequent assessment of residents by skilled gerontological nurses, whether in the community or in LTCFs, is essential. Nurses must learn to recognize signs of infection in the elderly and understand that because of suboptimal antibody response and normal aging changes, the elderly will frequently not exhibit symptoms most commonly associated with infection in younger persons.
An effective infection control program is the most important defense against nosocomial infection. By providing current policies, presenting effective educational programs, and instituting employee and resident health programs, infections can be prevented and perhaps eradicated. Infection control must be a top priority for all nurses who work with the elderly, because the end result of even a minor infection can be devastating.
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- 2. Gleckman RA, Gantz NM. Infections in the Elderly. Boston: Little, Brown & Co; 1983.
- 3. Smith PW. Infection Control in Long-Term Care Facilities. New York: John Wiley & Sons; 1984.
- 4. Gross PA, Rapuano C, Adringnolo A, Shaw B. Nosocomial infections: Decade-specific risk. Infection Control. 1983; 4: 1 45- 1 47.
- 5. Alvarez S, Shell CG, Wooley TW, Berk SL, Smith JK. Nosocomial infections in longterm facilities. J Gerontol. 1988; 43(1 ):M9M17.
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- 7. Smith PW. Nursing home acquired infections, what to do about control and treatment. Postgrad Med. 1987;81:55-66.
- 8. Garibaldi RA, Brodine S, Matsumiya S. Infections among patients in nursing homes - Policies, prevalence and problems. N Engl J Med. 1981;305:731-735.
- 9. Osier W. Principles and Practice of Medicine. New York: Appleton Davies; 1982.
- 10. Verghese A, Berk S. Bacterial pneumonia in the elderly. Medicine. 1983; 62:271-285.
- 11. Center for Disease Control. Impact of influenza on a nursing home population - New York. MAiWA. 1983;32(2):32-34.
- 12. Powell KE, Farer LS. The rising age of the tuberculosis patient: A sign of success and failure. J Infect Dis. 1980; 142:946-948.
- 13. Stead WW, Lofgren WE, Thomas C. Tuberculosis as an endemic and nosocomial infection among the elderly in nursing homes. N Engl J Med. 1 985; 3 1 2: 1 483- 1487.
- 14. Daly PB, Smith PW, Rusnak PG. Nursing home urinary catheter bacteria: Isolates and antibiotic sensitivities. Abstract presented at the 15th Annual APIC Educational Conference; May 1988; Dallas.
- 15. Warren JW, Tenney JH, Hoopes JM. A prospective microbiologic study of bacteriuria in patients with chronic indwelling urethral catheters. J Infect Dis. 1982; 146:719-723.
- 16. Berk SL, Alvarez S. Bacterial infections in the elderly. Postgrad Med. 1985; 77:168179.
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- 21. Vlahov D, Tenney JH, Cervino KW. Routine surveillance for infections in nursing homes: Experience at two facilities. Am J Infect Control. 1987; 15:47-53.
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THE EFFECT OF AGE ON THE IMMUNE SYSTEM3