Urinary Tract Infections in Long-Term Care
Friday, February 19, 2010 - 11:54
Urinary tract infections (UTIs) are the most common cause of bacteremia in long-term care (LTC) patients and may present with subtle nonspecific symptoms. UTIs should be suspected in older adults in LTC who manifest a sudden problem with incontinence, decreased physical or cognitive function, or loss of appetite. When a UTI is suspected, empiric antibiotics should be started based on the local infection pattern. Typically, trimethoprim/sulfamethoxazole is the major first-line empiric agent. Antibiotic prophylaxis to prevent UTIs may be required in postmenopausal women with frequent recurrent UTIs, patients about to undergo urologic or gynecologic procedures, patients with spinal cord injury, and men with chronic bacterial prostatitis. Although the high incidence of bacteriuria exists with the use of indwelling catheters, antibiotic prophylaxis is not recommended. Because asymptomatic bacteriuria does not require treatment, there is no role for periodic urine cultures in the chronically catheterized patient. (Annals of Long-Term Care: Clinical Care and Aging 2010; 18:35-39) Introduction/Epidemiology Lower urinary tract infections (UTIs) are a major cause of morbidity and mortality for adults in long-term care (LTC).1 Community studies have shown prevalence rates of bacteriuria to be 11% in the elderly, 18% for those living in congregate living arrangements, and 25-50% for residents in nursing home environments.2-4 In fact, the most common cause of bacteremia in LTC residents is due to UTIs.1 The prevalence of UTI increases in both sexes with age, resulting in a female-to-male ratio of 2:1 in the elderly population. The annual incidence of symptomatic bacterial UTIs is estimated to be as high as 10%. For asymptomatic bacteriuria, the estimated cumulative prevalence is 30% in women and 10% in men. Interestingly, the female-to-male ratio in the incidence of UTI narrows in the elderly population, which is thought to be related to the fact that with increasing age, men develop an increase in residual urinary volume after voiding, which increases their risk of bacteriuria and UTI; women engage in less sexual activity with age, and thus have one less predisposing risk factor for introduction of bacteria into the urinary tract. Sign and Symptoms UTIs are defined as infections of the urethra, bladder, ureters, and/or kidneys. Infections of the urethra and bladder are considered lower UTIs, while infections of the ureters or kidneys are considered upper UTIs. These infections can be classified according to localization as urethritis (urethra), cystitis (bladder), or pyelonephritis (kidney). In men, infections of the prostate gland (prostatitis) can mimic or complicate UTIs. They typically present with a classic triad of dysuria, urinary frequency, and suprapubic pain or discomfort. Other symptoms include recent incontinence, flank pain, fever, and/or lethargy. In the LTC patient, UTIs present with subtle nonspecific symptoms such as decreased appetite and/or oral intake, decreased physical activity, increased agitation, and/or combativeness. LTC patients might demonstrate recent onset of functional decline, anorexia, nausea, vomiting, or mental confusion. UTIs may also be classified by the presence (symptomatic) or absence (asymptomatic) of symptoms. Asymptomatic bacteriuria is defined as 105 colony-forming units (CFUs)/mL or more without symptoms or other signs of infection. Only about 70% of asymptomatic patients with high colony counts in a single urine sample have true bacteriuria as confirmed on a second sample. While defined by a single occurrence of infection, UTIs may be identified as sporadic, relapsing, or a re-infection. Sporadic infections are defined as 3 or more (or 2 or more, according to some investigators) episodes of asymptomatic bacteriuria within 1 year. Relapsing UTIs are defined as infections in which urine is rendered partially or temporarily sterile by antimicrobial therapy, with subsequent recurrence within 2 weeks of completion of therapy. Re-infection UTIs are defined as infections that arise 4 or more weeks after the previous infection has been cured. UTIs may also be classified as uncomplicated (or simple) versus complicated. Presence of urinary calculi, abscess formation, presence of a urinary catheter, and obstructive uropathy are considered complicated UTIs. Pathophysiology The most common cause of a bacterial UTI in the LTC setting is infection by Escherichia coli. E. coli accounts for up to 70% of bacteriuria in elderly female outpatients with uncomplicated sporadic cystitis and for about 40% in patients with indwelling bladder catheters.5,6 However, polymicrobial infections occur more frequently in the LTC resident. Klebsiella sp, especially K. pneumoniae, are the second most commonly isolated gram-negative, aerobic pathogens. The third most common organisms are Proteus mirabilis, P. vulgaris, P. inconstans, and Morganella morganii; these tend to be more common pathogens in men as compared to women. They are also seen more in patients with urinary calculi because the organisms tend to thrive in an alkaline milieu. Proteus species, Providencia species, and M. morganii are common isolates in patients with indwelling catheters. With recurrent infections, resistant gram-negative bacteria other than E. coli and gram-positive bacteria tend to predominate. Enterococcal super-infection often results from frequent use of antibiotics that are inactive against these organisms. Serratia, Citrobacter, Acinetobacter, Enterobacter, Enterococcus, and Pseudomonas aeruginosa are common isolates in nosocomial infections. Organisms such as lactobacilli, alpha-hemolytic Streptococcus, and anaerobes do not grow well in urine and are usually considered nonpathologic contaminants when isolated in urine. Risk Factors Certain age-related factors place older adults at greater risk for UTIs. Functional status, physical impairments, as well as genitourinary procedures, anatomy, and function predict how likely bacteriuria and UTIs are to develop. A number of anatomical and functional changes occur to the lower urinary tract with aging. In postmenopausal women, a decline in estrogen leads to an increase in vaginal pH, atrophy of pelvic structures, and urethral weakness, which leads to an increased susceptibility to UTIs. The vaginal epithelium becomes atrophied and dry, and may become inflamed, thus contributing to UTI. In men, prostatic hypertrophy can lead to large post-void residuals, with urine remaining stagnant and providing other opportunities for bacteriuria and UTI.7 Alterations in immune function may affect susceptibility to infection. Immobility, medications that affect bladder emptying such as anticholinergics, and poor perineal hygiene all may predispose the elderly patient to developing UTIs. Diagnosis Diagnosis of a symptomatic UTI can be challenging in the LTC setting. Any acute deterioration in stable chronic conditions may indicate the infection. To aid in the diagnosis of symptomatic UTI, the definition used by McGeer and MeSH may be helpful.8 To meet criteria used for LTC residents without an indwelling catheter, three of the following should be present: • Fever (an increase in temperature > 2° F [1.1° C] or rectal temperature > 99.5° F [37.5° C] or oral temperature > 100° F [37.8° C]) • New or increase in burning pain on urination, frequency, or urgency • New flank or suprapubic pain or tenderness • Change in the character of the urine (foul smell, amount, sediment, blood, etc) or new pyuria or hematuria • Worsening of mental or physical functioning (confusion, decreased appetite, unexplained falls, recent incontinence, lethargy, or decreased activity) In LTC residents with a catheter, two of the following should be present: • Fever or chills • New flank or suprapubic pain or tenderness • Change in the character of the urine (foul smell, amount, sediment, blood, etc) or new pyuria or hematuria • Worsening of mental or physical functioning (confusion, decreased appetite, unexplained falls, recent incontinence, lethargy, or decreased activity) To confirm the diagnosis of a UTI, a clean-catch urine specimen is required. Although technically challenging, a clean-catch urine specimen from incontinent, cognitively-impaired men and women is possible. Carefully cleaning the perineum and having the patient void into a disinfected collection device or “hat” for women and using condom catheters for men will usually suffice. When functional impairment inhibits the suitable collection of a urine specimen, in-and-out catheterization should be used. Rapid tests may be useful in determination of bacteriuria. The most reliable rapid test is the nitrite test, in which the conversion of nitrate to nitrite by bacteria in the urine is demonstrated by color change on dipstick analysis. This test has a high positive predictive value of 88.2% and specificity of 96.6%, but does not demonstrate bacteriuria caused by Pseudomonas, Staphylococcus, or Enterococcus, which are incapable of metabolizing nitrate.9 However, a positive nitrite or leukocyte esterase test alone does not prove that a patient has a UTI. Asymptomatic Bacteriuria Laboratory confirmation of 105 CFUs/mL or more is the standard definition of a positive urine culture by the Association for Professionals in Infection Control and Epidemiology (APIC). When a positive culture is identified in a patient without dysuria, frequency, incontinence, pain, fever, or other signs of infection, this is considered asymptomatic bacteriuria. The clinical significance of asymptomatic bacteriuria in the elderly is unclear. The vast majority of elderly patients with bacteriuria are asymptomatic, and when questioned about symptoms of incontinence, frequency, or urgency, no significant differences have been found between patients with and without bacteriuria. The majority of data indicate that asymptomatic bacteriuria in the elderly does not lead to renal damage.3 Bacteriuria clears spontaneously or occurs intermittently in the majority of patients. Asymptomatic bacteriuria in the elderly is a benign condition that does not require treatment. Treatment reduces neither morbidity nor mortality but may increase the likelihood of drug-resistant microorganisms and adverse reactions to antibiotics. Exceptions to this principle are patients who are scheduled for a genitourinary procedure or who have obstructive uropathy, infectious stones, or a history of recurrent symptomatic infections. Prevention Some situations require antibiotic prophylaxis to prevent UTIs. Postmenopausal women with frequent recurrent UTIs, patients about to undergo urologic or gynecologic procedures, persons with spinal cord injury, and men with chronic bacterial prostatitis may benefit from antibiotic prophylaxis.10,11 Other behaviors that may have potential effects on the development of UTIs have been less thoroughly investigated and include increased fluid intake, increased voiding, and micturition after intercourse.11 In women, local treatment with topical estrogens significantly reduces the pH of the vagina, reduces colonization with gram-negative bacilli, and decreases the incidence of UTIs. Some research suggests that ingestion of commercially available cranberry juice or vitamin C in moderate amounts may be useful in preventing UTIs, mostly through effects on urinary pH.12 These agents have actually been found to be useful in the treatment of UTI through their effects on urinary pH; however, when used in the absence of a UTI or bacteriuria they could induce urinary frequency and urgency. Management Managing UTIs in LTC can present a variety of challenges. The unique features of UTIs in elderly LTC patients have led to the development of recommendations on management. The American Medical Directors Association has released guidelines on the management of UTIs in LTC, which can be accessed at http://www.amda.com/tools/cpg/infections.cfm. Pharmacologic Management If prevention fails and infection occurs, the ideal management for acute UTIs is to identify the causative organism and administer systemic antibiotics to treat the infection. However, treatment should not be delayed pending the results of a urine culture. Once the suspicion of a UTI has reached the treatment threshold, empiric antibiotics should be considered.13 The choice of agent should be guided by the local prevalence of a causative organism or general prevalence data. If the local prevalence is unknown, trimethoprim/sulfamethoxazole 160/800 mg twice daily for 3-7 days is generally recommended for empiric treatment of simple uncomplicated UTI. Symptomatic infections should be promptly treated after a Gram stain and appropriate cultures of the urine are obtained. Clinically unstable patients or patients who appear severely ill should be hospitalized and treated with parenteral antibiotics. If patients are able to receive treatment in a nursing home but require parenteral antibiotics, second- and third-generation cephalosporins may be administered intramuscularly. Noncatheterized patients who are able to receive treatment with oral agents can be treated with trimethoprim/sulfamethoxazole, amoxicillin, amoxicillin-clavulanic acid, second-generation cephalosporins, or fluoroquinolones. Duration of antibiotic therapy is generally 10-14 days in the elderly; shorter treatment regimens of 3-5 days are not satisfactory in the elderly patient. In the elderly patient it may be difficult to differentiate re-infection from relapse. When possible, an attempt to distinguish between the two is useful because relapse may require further evaluation. Relapse in elderly patients may result from incomplete bladder emptying caused by neuropathy from diabetes mellitus, uterine prolapse, or prostatic hypertrophy. Genitourinary evaluation should include determination of renal function, quantitation of postvoid residuals, ultrasound, and urologic evaluation to determine if obstructive uropathy or other genitourinary abnormalities are present. After resolution of symptoms and/or completion of the antibiotic treatment, a follow-up urine specimen should be collected to validate the eradication of UTI after completion of the course of antibiotics. In men for whom relapse UTI is found to be as a result of bacterial prostatitis, antimicrobial therapy with an oral fluoroquinolone or trimethoprim/sulfamethoxazole should be used for at least 4 weeks.13 Special Considerations Complicated (Persistent) UTI Distinction between uncomplicated and complicated UTI is important because of the implications regarding pretreatment and posttreatment evaluation, type and duration of antimicrobial regimens, and extent of evaluation of the urinary tract. Complicated or persistent UTI refers to infections that fail to resolve or recur within 2 weeks after standard therapy. These UTIs are associated with bacteremia or sepsis and are associated with periurethral abscess, obstructions, and pyelonephritis. Complicated UTIs occur in patients with structurally or functionally abnormal urinary tracts and may involve antibiotic-resistant pathogens. Structural complications that precipitate complicated UTI include intrinsic abnormalities such as renal stones, prostatic hypertrophy, neurogenic bladder, or the presence of external devices such as indwelling urethral catheters. Patients with a complicated UTI should be evaluated for structural and functional abnormalities with an ultrasound or intravenous pyelogram and voiding cystourethrogram. Patients with impaired renal function can be evaluated with a radionuclide renal scan or an ultrasound. Elderly men should be evaluated for prostatic enlargement. The presence of infected stones is associated with urease-producing bacteria, most frequently Proteus species. Treatment consists of stone removal and culture-specific antibiotics. Once the stone is removed, the urine should be kept sterile by continuous antibiotic therapy for 1 month.14 Periurethral abscess is an uncommon but life-threatening infection of the male urethra and periurethral tissue. Periurethral abscess is usually associated with the presence of Foley catheters. Symptoms include fever, positive urinalysis, scrotal/labial or penile swelling, and erythema. Therapy requires combination intravenous antibiotics with a cephalosporin and aminoglycoside for 10-14 days. Catheter-Associated Bacteriuria and UTIs Most patients with short-term indwelling catheters will be residents of acute care institutions. Most long-term indwelling catheters are used in patients in a nursing home setting. When necessary, the use of clean intermittent catheterization is preferred over the use of long-term indwelling catheters. Condom catheters may also be appropriate for some men, especially since condom catheters are more comfortable than indwelling catheters.15 Bacteriuria is an inevitable event in patients requiring indwelling catheters, with virtually every patient developing colonization within 1 month of catheter placement.16 Indwelling urinary catheters are the leading cause of nosocomial UTIs and the most common predisposing factor in hospital-acquired, fatal gram-negative sepsis. Because of this high rate of morbidity, the Centers for Medicare & Medicaid Services have a revision to their Guidance to Surveyors that focuses on urinary incontinence and UTIs under Tag F315.17 Section 483.25(d) number 2 states that “a resident who is incontinent of bladder receives appropriate treatment and services to prevent urinary tract infections and to restore as much normal bladder function as possible.” Both APIC and the Centers for Disease Control and Prevention have developed recommendations to prevent catheter-associated UTIs. Adherence to sterile technique for catheter insertion and the use of a continually closed drainage system are the cornerstones of preventing catheter-associated UTIs.18 Maintenance of unobstructed urine flow to a bag below the level of the bladder, properly securing the catheter to prevent movement and urethral traction, and removal of catheters when no longer needed are important steps to prevent catheter-associated UTIs. Interventions such as topical meatal antimicrobials, disinfectants added to the urinary drainage bag, antimicrobial coatings for catheters, and antimicrobial irrigations have not been shown to decrease the incidence of infection. Additional complications of long-term catheterization include nonbacterial urethritis, nephrolithiasis, cystolithiasis, chronic renal inflammation, chronic pyelonephritis, bacteremia, and death. Although the high incidence of bacteriuria exists with the use of indwelling catheters, antibiotic prophylaxis is not recommended.10 Prophylaxis may be associated with the development of antibiotic-resistant microbes. Because asymptomatic bacteriuria does not require treatment, there is no role for periodic urine cultures in the chronically catheterized patient. Catheterized residents who have active UTIs will generally not have classic symptoms. In these patients, fever, cognitive impairment, functional changes, changes in appetite, tachypnea, tachycardia, and hypotension are more likely to be the presenting symptoms. When the patient with an indwelling catheter does develop symptoms of a UTI, a common practice is to insert a new catheter for collecting a urine sample for identification of the organism, although data do not exist to support this practice. Urinary infections in patients with indwelling catheters are often polymicrobial and may include such organisms as Pseudomonas, Proteus, Klebsiella, and Enterococci. Among short-term catheterized patients, E. coli remains the most frequent bacteriuric species isolated.15 When a UTI is suspected, empiric antibiotics should be started. Once the particular pathogen is identified, the antibiotic should be adjusted. The selection of empiric antibiotics should be based on knowledge of common organisms in the care unit because the majority of the bacteria-causing, catheter-associated bacteriuria are from the patient’s own colonic flora, including those recently acquired from a hospital environment. Because of the possibility of polymicrobial infection, appropriate empiric treatment should include a parenteral or oral regimen that is effective against both gram-negative bacilli and Enterococci. Seriously ill or septic patients require a two-drug combination such as ampicillin and a third-generation cephalosporin (eg, fluoroquinolone, aztreonam, or an aminoglycoside). Duration of antibiotic therapy is generally 10-14 days. Candiduria Yeast in the urine may be isolated when antibiotics are used frequently. Candiduria may develop in catheterized patients, and its incidence is directly related to duration of catheterization.16 Removal of the catheter results in the disappearance of candiduria in one-third of patients.16 Patients in whom candiduria persists or who are symptomatic can be treated with oral fluconazole. Only two catheter hygiene principles are universally recommended to prevent infections in chronically catheterized patients: One is to keep the catheter system closed, obtaining urine specimens by needle and syringe without opening the catheter-collection tube; and the second principle is to remove the catheter as soon as medically possible.16 Methicillin-Resistant Staphylococcus aureus and Vancomycin-Resistant Enterococcus Patients in LTC environments are at risk for colonization with resistant organisms such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). For VRE, urine is the most common source.19 Often, when detected by urine cultures, these infections represent asymptomatic bacteruria with an approach to management that has been discussed previously. An important concern regarding the management of these resistant infections is to prevent other LTC residents from being exposed to them. Unfortunately, no evidence demonstrates that the use of barrier methods prevents illness or death from MRSA and VRE in LTC facilities.20 Moreover, many interventions have failed to show a decrease in morbidity from these infections in LTC.21 Yet it is still recommended that the following precautions be applied: 1. LTC patients colonized or infected with MRSA or VRE should wash hands after any personal hygiene activities and prior to leaving their rooms for group activities; 2. Employees should wear gloves when providing care that involves any personal contact with the resident or contaminated equipment or supplies. During the course of providing care, if hands have become soiled with potentially infectious material or body excretions, gloves should be changed and hands washed before further contact with clean surfaces or other persons; 3. Appropriate hand technique should be followed with care taken to avoid touching environmental surfaces, equipment, or supplies, or other persons after caring fora resident colonized or infected with VRE and prior towashing hands; 4. Cover gowns should be worn if the provider’s clothing is likely to have substantial contact with the body fluids known to be colonized or infected with VRE. Gowns should be removed immediately following such care.19 Conclusion Lower UTIs are an important cause of morbidity and mortality in LTC patients. These infections are the leading cause of septicemia in the nursing home population. Since the symptoms of UTIs are often subtle, clinicians should have a high index of suspicion in residents who have an unexplained sudden decline in function.21 For these patients, a clean-catch urine specimen demonstrating pathogenic microorganisms is diagnostic and indicates a need to initiate treatment. Prompt treatment can avoid untoward outcomes and sometimes reverse any decline associated with UTIs. The authors report no relevant financial relationships. From the Department of Community and Family Medicine, Howard University College of Medicine, Washington, DC.
Related Articles‹ Previous articleNext article ›