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Urinary-catheter-associated infections in the elderly
International Journal of Antimicrobial Agents 28S (2006) S78–S81
Urinary-catheter-associated infections in the elderly Calvin M. Kunin ∗ Department of Internal Medicine, Ohio State University, Columbus, OH, USA
Abstract The indwelling urinary catheter is the leading cause of complicated urinary tract infections and Gram-negative bacteraemia in this age group. It accounts for about 40% of life-threatening septicaemia. There is a progressive increase in mortality independently associated with the duration of catheterization. Polymicrobial bacteriuria is common. Urease-producing bacteria lead to encrusted and blocked catheters. The current challenges are to develop effective methods to sensitize healthcare workers to avoid the routine use of indwelling catheters, remove them when no longer needed, develop alternative methods for care of incontinence, employ non-invasive methods to measure urine output, and improve urine drainage systems. The research paradigm needs to focus on prevention of catheter-associated infections rather than on futile attempts to treat irreversible sepsis. © 2006 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved. Keywords: Urinary infection; Elderly; Long-term catheterization
1. Introduction The urinary catheter is an essential part of modern medical care. It is widely used to relieve anatomic or physiological obstruction, facilitate surgical repair of the urethra and surrounding structures, provide a dry environment for comatose or incontinent patients, and permit accurate measurement of urinary output in severely ill patients. Unfortunately, when used inappropriately or left in place too long, the catheter is a hazard to the very patients it is designed to protect [1]. The indwelling urinary catheter is the leading cause of nosocomial urinary tract infection (UTI) and Gram-negative bacteraemia [2]. Systemic antimicrobial therapy may temporarily reduce the bacterial count in the bladder urine, but cannot eradicate infections in patients with indwelling urinary catheters [3,4]. Inappropriate and excessive use of antimicrobial drugs in catheterized patients leads to the selection of antibiotic-resistant microorganisms and accounts for nosocomial outbreaks of infection with multiresistant strains. Catheters drain the bladder, but obstruct the urethra. Indwelling urethral catheters can produce urethral strictures, epididymitis, orchitis and prostatitis in males. The current challenges are to develop effective methods to ∗
Tel.: +1 614 488 3634; fax: +1 614 293 6890. E-mail address: [email protected].
sensitize the minds of healthcare workers to avoid the routine use of indwelling catheters, remove catheters when they are no longer needed, develop alternative methods for care of incontinence, employ non-invasive methods to measure bladder function and urine output, and improve urine drainage systems. About 5–10% of residents of long-term care facilities are managed with long-term indwelling catheters [5]. The urine of virtually all of these patients is persistently colonized with multiple species of microorganisms. It is therefore not surprising that the urinary tract accounts for 51–56% of episodes of often polymicrobial bacteraemia [6–8]. Long-term use of the urinary catheter is the most likely source of urosepsis in patients over 60 years of age [9]. Bacteraemia is complicated by septic shock in about one-third. The overall case fatality in bacteraemic patients ranges from ca. 18% to 21.5% [6–8]. Medicare administrative data show that the US rates of hospitalization for septicaemia increased between 1986 and 1997 from 3.42 to 7.42 per 1000 beneficiaries [10]. The rates were even higher (18.1 per 1000) among people aged >85 years in 1997. The urinary tract was the most common site, accounting for 40.1% of hospitalizations. The 30-day post-hospital mortality for all patients was 6.8% but rose to about 25% for those with septicaemia. The estimated annual cost to Medicare in 1997 for management of septicaemia was USD 1.8 billion. This did not include an additional 20% for physicians’
0924-8579/$ – see front matter © 2006 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved. doi:10.1016/j.ijantimicag.2006.05.013
C.M. Kunin / International Journal of Antimicrobial Agents 28S (2006) S78–S81
services and costs for out-patient care, home health agencies, skilled nursing homes and rehabilitation facilities. The typical cases are either a debilitated elderly woman with a urinary catheter who presents with altered mental status, dehydration, fever and hypotension, or an elderly man who has recently underwent a traumatic catheterization to relieve obstruction. The most common microorganisms are those associated with complicated UTI. Escherichia coli is most common, followed by Proteus mirabilis, Klebsiella pneumoniae and Pseudomonas aeruginosa.
2. Illustrative case A 74 year-old widow with long-term diabetes and dementia was referred to an emergency department from a nursing home because of progressive obtundation, fever and dyspnoea. She had been incontinent of urine and stool and managed for over 1 year with an indwelling urinary catheter. She had several prior hospitalizations for sepsis, dehydration and poorly controlled diabetes. She had been treated numerous times for febrile episodes with a variety of antibiotics including ampicillin and ciprofloxacin. The diabetes was managed with oral drugs. On physical examination she was a cachectic, semicomatose elderly woman. Her skin was dry and pale. An ammonia-like odour was noted. Her blood pressure was 70/50 mmHg, temperature 97 ◦ F (36.1 ◦ C), respiration 30 breaths/min, and pulse 120 beats/min and regular. There were no abnormal findings in the head, chest, abdomen or extremities. There were no localizing neurological signs. Her neck was supple. The urinary catheter was removed. It was heavily encrusted and virtually blocked. Laboratory findings included a white blood cell count of 16 000, with 85% polymorphonuclear leucocytes, 6% band neutrophils and 40% haematocrit. The serum sodium was 156 mmol/L, potassium 5.6 mmol/L, creatinine 3.5 mg/dL, blood urea nitrogen 68 mg/dL and glucose 420 mEq/dL. Blood pH was 7.1. Her urine was loaded with white blood cells; there were 4+ bacteria, leucocyte esterase (+), nitrite (+), and pH was 8. The urine culture was reported to contain >105 colony-forming units/mL of Providencia stuartii, Enterococcus faecalis and E. coli. Blood cultures obtained from two separate venous sites were positive for E. coli. The chest X-ray showed clear lung fields without cardiomegaly. Renal ultrasound showed a massively enlarged right kidney with echogenic focus in the right renal pelvis. She was treated with intravenous fluids, pressors, insulin and the antibiotics ‘du jour’ (those available at the time). The abscess was drained percutaneously, but the stone was not removed because of her high surgical risk. She survived a prolonged hospitalization complicated by arrhythmias, pulmonary emboli and an intravenous line infection. The microorganisms were temporarily eradicated from the urine, but multi-antibiotic resistant strains of P. stuartii together with Candida albicans re-emerged during therapy. She was
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Table 1 Key points about the use of indwelling catheters in nursing homes [1] • Indwelling catheters are used in ca. 7.5–10% of patients in many facilities • Lower rates are achieved by use of prompted voiding and incontinence pads • All patients catheterized for more than 1 month will have a urinary tract infection • Antibiotics are overused in nursing homes and are inappropriate 50% of the time • Multiresistant polymicrobial bacteriuria is common in catheterized patients • Bacteraemia is often silent; occurring in 10% of patients with a catheter change • Fever is uncommon, transient and low grade, but is an important finding • Urosepsis is a common cause for hospitalization • Silent pyelonephritis is present at autopsy in ca. one-third of patients • Catheter-associated infections are an independent risk factor for death Table 2 Complications of indwelling catheters [1] • Urinary tract infection • Acute pyelonephritis • Bacteraemia and sepsis • Formation of encrustations and obstruction to flow • Urethral strictures, prostatitis and orchitis • Acquisition and spread of yeasts and multiresistant bacteria • Increased mortality among bacteriuric patients with long-term catheters • Prolonged hospital stay • Increased costs for antimicrobial agents and management of sepsis • Late sequelae include metastatic osteomyelitis and meningitis
returned to the nursing home. She was found dead 30 days later. An autopsy was not performed.
3. Complications of indwelling catheters in the elderly This case illustrates several key points about the use of indwelling catheters in the elderly (Table 1) [1]. The complications of long-term use of indwelling catheters are summarized in Table 2 [1]. This case also illustrates the ‘blocker’ phenomenon [11] that occurs in patients colonized with ureasplitting microorganisms (Tables 3 and 4) [1]. The patient was managed according to the principles outlined in Table 5, but died 30 days after discharge. The outcome in this case is not surprising in view of the high post-hospital mortality noted in the Medicare study cited above [10]. Table 3 Major urease-producing microorganisms [1] • Proteus mirabilis, Proteus vulgaris • Providencia stuartii • Morganella morganii • Staphylococcus saprophyticus • Corynebacterium urealyticum • Mycoplasma urealyticum
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C.M. Kunin / International Journal of Antimicrobial Agents 28S (2006) S78–S81
Table 4 Sequential dangers of urease production • Hydrolyses urea to CO2 and NH3 • Alkalinizes the urine to >pH 8.0 • Forms precipitates of struvite crystal (Mg2 , NH4 , phosphate) • Obstructs urinary catheters • Forms infection stones • Produces urinary obstruction • Leads to persistent infection
The effects of long-term urinary catheterization among elderly patients in long-term nursing home facilities are usually less dramatic than in the illustrative case. Catheterassociated UTIs are rarely symptomatic [12]. We conducted a 1-year prospective study of 1540 nursing home patients in a stratified sample of extended care facilities in Columbus, Ohio [13]. The indwelling urinary catheter was found to be an independent risk factor for death. There was a linear relationship between duration of catheterization and death after adjustment for confounding factors including age, activities of daily living, cancer, heart disease, diabetes and decubitus ulcers (Table 6). Patients who were catheterized for 76% or more of their days in the nursing homes were three times more likely to die within 1 year. The number of hospitalizations, duration of hospitalization and use of antimicrobial drugs among this group were three times greater than among noncatheterized patients.
Table 5 Management of sepsis in catheterized patients • Clues are altered mental status, anorexia, low-grade fever and hypotension • Remove the catheter and inspect for encrustations and blockage • Do not insert a new catheter unless there is obstruction • Obtain blood and urine cultures; find out what antimicrobial drugs were used recently • Suspect urease-producing bacteria – Proteus, Providencia and Morganella – with blocked catheters and alkaline urine • Gram stain the urine to determine Gram-positive and Gram-negative bacteria and yeasts • Replete fluids and electrolytes and use pressor drugs as necessary • Obtain an ultrasound of the kidneys and bladder for obstruction and stones • Assume the patient is infected with several multiresistant uropathogens. E. coli has special epidemic virulence • Initiate presumptive therapy with an extended-spectrum penicillin, cephalosporin or fluoroquinolone with optional use of an aminoglycoside. Add drugs effective against enterococci and yeasts if Gram-positive cocci in chains or yeasts are seen in the urine • Simplify therapy to a single drug as soon as susceptibility data are available • The optimum duration of therapy is unknown, but need not exceed 1 week • Re-evaluate the need for an indwelling catheter
Table 6 Effect of duration of catheterization on mortality among 1540 nursing home patients observed for 1 year after adjustment for all other risk factors [13] Days (%)
Deaths (%)
Adjusted OR
None 1–25 26–75 78–100
16.4 23.7 35.8 43.6
1.00 1.35 2.09 2.99
OR, odds ratio. For all durations P < 0.01.
4. The need for renewed attention to the indwelling urinary catheter One would expect that prevention of catheter-associated infection would have a very high priority for government- and healthcare-industry-sponsored research. The Centers for Disease Control and Prevention (CDC) and hospitals continue to emphasize surveillance. This documents the problem, but does not provide solutions. The CDC guidelines for prevention of catheter-associated infections have not been updated since 1983 [14]. The National Institutes of Health sponsors a great deal of research focused on molecular mechanisms of sepsis, but not the cause. Most of the innovations in this field have come from the equipment manufacturers. There has been very little motivation for true innovation except for the relatively recent development of antimicrobial-impregnated catheters [15], conformable catheters [16] and novel methods to prevent catheter encrustations [17]. Catheters and drainage bag systems are considered to be a commodity competing for the lowest expenditures hospitals will support. There appears to be minimal oversight by the Food and Drug Administration. The only effective control is competition among manufacturers and the efforts of a small cadre of devoted clinical investigators. The mechanisms by which indwelling catheters produce infection are now well established. These consist initially of ascending colonization of the urine within the catheter lumen and eventually along the space between the urethra and catheter surface [1,15]. The technological requirements to design better catheters and drainage systems are fairly well known [18]. Dukes demonstrated the efficacy of closed drainage to block ascending infection in 1928 [19]. Disposable closed drainage systems became widely available almost 40 years ago [20]. None of the numerous attempts to improve the system have been shown to be more effective than simple closed drainage. Attempts to block the periurethral route by coating catheters with antimicrobial agents are currently receiving considerable attention. However, even if this were effective in the short term, they would be ineffective after the acquisition of bacteriuria in extended care settings. Catheters are fairly rigid structures. They drain the bladder, but block the urethra. The challenge is to produce an instrument that matches as closely as possible the normal physiological and mechanical characteristics of the voiding system. This requires construction of a thin-walled, continuously lubricated, collapsible (conformable) catheter to pro-
C.M. Kunin / International Journal of Antimicrobial Agents 28S (2006) S78–S81
tect the integrity of the urethra; a system to hold the catheter in place without a balloon; and to imitate the intermittent washing of the bladder urine. The efficacy of each component of the system will need to be evaluated in carefully conducted, controlled clinical trials. There is also a major need for better fitting male condom catheters and for external urine collection devices for incontinent females. Catheters of the future may be more expensive, but may be well worth the investment if used in the appropriate population. There is no need to wait for a mechanical or chemical answer to the problem of nosocomial UTIs. The culprit is unnecessary and prolonged use of catheters when these are no longer needed [21–23]. Improvements in catheter and drainage systems are welcome, but cannot substitute for thoughtful care. The major reasons for the use of indwelling urinary catheters in nursing homes are incontinence and management of decubitus ulcers. There are now several methods to deal with incontinence including prompted voiding, pharmacological agents and oestrogen therapy [24,25]. Hebel and Warren pointed out many years ago that ‘because urethral catheterization may be used as a management technique for decubitus ulcers, prevention of the latter may diminish the use of urethral catheters and their subsequent complications’ [26]. We must ask ourselves on daily rounds, ‘Is this catheter really necessary? When can I take it out? Are there alternative measures? Can a portable ultrasound help determine when a catheter may be required?’
Acknowledgment This article is based on a presentation at the 24th International Congress of Chemotherapy, held in Manila, The Philippines, 4–6 June 2005. The author has no conflicts of interest.
References [1] Kunin CM. Urinary tract infections. Detection, prevention and management. 5th ed. Baltimore: Williams & Wilkins; 1997. [2] Centers for Disease Control (CDC). Public health focus: surveillance, prevention, and control of nosocomial infections. MMWR Morb Mortal Wkly Rep 1992;41:783–7. [3] Britt MR, Garibaldi RA, Miller WA, Hebertson RM, Burke JP. Antimicrobial prophylaxis for catheter-associated bacteriuria. Antimicrob Agents Chemother 1977;11:240–3. [4] Warren JW, Anthony WC, Hoopes JM, Muncie Jr HL. Cephalexin for susceptible bacteriuria in afebrile, long-term catheterized patients. J Am Med Assoc 1982;248:454–8. [5] Nicolle LE. Urinary tract infection in long-term-care facility residents. Clin Infect Dis 2000;31:757–61.
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[6] Setia U, Serventi I, Lorenz P. Bacteremia in a long-term care facility. Spectrum and mortality. Arch Intern Med 1984;144:1633–5. [7] Muder RR, Brennen C, Wagener MM, Goetz AM. Bacteremia in a long-term-care facility: a five-year prospective study of 163 consecutive episodes. Clin Infect Dis 1992;14:647–54. [8] Mylotte JM, Tayara A, Goonough S. Epidemiology of bloodstream infection in nursing home residents: evaluation in a large cohort from multiple homes. Clin Infect Dis 2002;35:1484–90. [9] Rosser CJ, Bare RL, Meredith JW. Urinary tract infections in the critically ill patient with a urinary catheter. Am J Surg 1999;177:287– 90. [10] McBean M, Rajamani S. Increasing rates of hospitalization due to septicemia in the US elderly population, 1986–1997. J Infect Dis 2001;183:596–603. [11] Kunin CM, Chin QF, Chambers S. Formation of encrustations on indwelling catheters in the elderly: a comparison of different types of catheter materials in “blockers” and “nonblockers”. J Urol 1987;138:899–902. [12] Tambyah PA, Maki DG. Catheter-associated urinary tract infection is rarely symptomatic: a prospective study of 1,497 catheterized patients. Arch Intern Med 2000;160:678–82. [13] Kunin CM, Douthitt S, Dancing J, Anderson J, Moeschberger M. The association between the use of urinary catheters and morbidity and mortality among elderly patients in nursing homes. Am J Epidemiol 1992;135:291–301. [14] Wong ES. Guidelines for prevention of catheter-associated urinary tract infections. Am J Infect Control 1983;11:28–33. [15] Maki DG, Tambyah PA. Engineering out the risk for infection with urinary catheters. Emerg Infect Dis 2001;7:342–7. [16] Brocklehurst JC, Hickey DS, Davies I, Kennedy AP, Morris JA. A new urethral catheter. Br Med J (Clin Res Ed) 1988;296: 1691–3. [17] Strickler DJ, Jones GL, Russell AD. Control of encrustation and blockage of Foley catheters. Lancet 2003;361:1435–7. [18] Kunin CM. Can we build a better catheter? N Engl J Med 1988;319:365–6. [19] Dukes C. Urinary infections after excision of the rectum: their cause and prevention. Proc R Soc Med 1928;22:256–67. [20] Kunin CM, McCormack RC. Prevention of catheter-induced urinarytract infections by sterile closed drainage. N Engl J Med 1966;274:1155–61. [21] Jain P, Parada JP, David A, Smith LG. Overuse of the indwelling urinary tract catheter in hospitalized medical patients. Arch Intern Med 1995;155:1425–9. [22] Saint S, Lipsky BA, Goold SD. Indwelling urinary catheters: a onepoint restraint? Ann Intern Med 2002;137:125–7. [23] Huang WC, Wann SR, Lin SL, et al. Catheter-associated urinary tract infections in intensive care units can be reduced by prompting physicians to remove unnecessary catheters. Infect Control Hosp Epidemiol 2004;25:974–8. [24] Stern JA, Hsieh YC, Schaeffer AJ. Residual urine in an elderly female population: novel implications for oral estrogen replacement and impact on recurrent urinary tract infection. J Urol 2004;171:768–70. [25] Ouslander JG. Management of overactive bladder. N Engl J Med 2004;350:786–99. [26] Hebel JR, Warren JW. The use of urethral, condom, and suprapubic catheters in aged nursing home patients. J Am Geriatr Soc 1990;38:777–84.
Urinary-catheter-associated infections in the elderly Calvin M. Kunin ∗ Department of Internal Medicine, Ohio State University, Columbus, OH, USA
Abstract The indwelling urinary catheter is the leading cause of complicated urinary tract infections and Gram-negative bacteraemia in this age group. It accounts for about 40% of life-threatening septicaemia. There is a progressive increase in mortality independently associated with the duration of catheterization. Polymicrobial bacteriuria is common. Urease-producing bacteria lead to encrusted and blocked catheters. The current challenges are to develop effective methods to sensitize healthcare workers to avoid the routine use of indwelling catheters, remove them when no longer needed, develop alternative methods for care of incontinence, employ non-invasive methods to measure urine output, and improve urine drainage systems. The research paradigm needs to focus on prevention of catheter-associated infections rather than on futile attempts to treat irreversible sepsis. © 2006 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved. Keywords: Urinary infection; Elderly; Long-term catheterization
1. Introduction The urinary catheter is an essential part of modern medical care. It is widely used to relieve anatomic or physiological obstruction, facilitate surgical repair of the urethra and surrounding structures, provide a dry environment for comatose or incontinent patients, and permit accurate measurement of urinary output in severely ill patients. Unfortunately, when used inappropriately or left in place too long, the catheter is a hazard to the very patients it is designed to protect [1]. The indwelling urinary catheter is the leading cause of nosocomial urinary tract infection (UTI) and Gram-negative bacteraemia [2]. Systemic antimicrobial therapy may temporarily reduce the bacterial count in the bladder urine, but cannot eradicate infections in patients with indwelling urinary catheters [3,4]. Inappropriate and excessive use of antimicrobial drugs in catheterized patients leads to the selection of antibiotic-resistant microorganisms and accounts for nosocomial outbreaks of infection with multiresistant strains. Catheters drain the bladder, but obstruct the urethra. Indwelling urethral catheters can produce urethral strictures, epididymitis, orchitis and prostatitis in males. The current challenges are to develop effective methods to ∗
Tel.: +1 614 488 3634; fax: +1 614 293 6890. E-mail address: [email protected].
sensitize the minds of healthcare workers to avoid the routine use of indwelling catheters, remove catheters when they are no longer needed, develop alternative methods for care of incontinence, employ non-invasive methods to measure bladder function and urine output, and improve urine drainage systems. About 5–10% of residents of long-term care facilities are managed with long-term indwelling catheters [5]. The urine of virtually all of these patients is persistently colonized with multiple species of microorganisms. It is therefore not surprising that the urinary tract accounts for 51–56% of episodes of often polymicrobial bacteraemia [6–8]. Long-term use of the urinary catheter is the most likely source of urosepsis in patients over 60 years of age [9]. Bacteraemia is complicated by septic shock in about one-third. The overall case fatality in bacteraemic patients ranges from ca. 18% to 21.5% [6–8]. Medicare administrative data show that the US rates of hospitalization for septicaemia increased between 1986 and 1997 from 3.42 to 7.42 per 1000 beneficiaries [10]. The rates were even higher (18.1 per 1000) among people aged >85 years in 1997. The urinary tract was the most common site, accounting for 40.1% of hospitalizations. The 30-day post-hospital mortality for all patients was 6.8% but rose to about 25% for those with septicaemia. The estimated annual cost to Medicare in 1997 for management of septicaemia was USD 1.8 billion. This did not include an additional 20% for physicians’
0924-8579/$ – see front matter © 2006 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved. doi:10.1016/j.ijantimicag.2006.05.013
C.M. Kunin / International Journal of Antimicrobial Agents 28S (2006) S78–S81
services and costs for out-patient care, home health agencies, skilled nursing homes and rehabilitation facilities. The typical cases are either a debilitated elderly woman with a urinary catheter who presents with altered mental status, dehydration, fever and hypotension, or an elderly man who has recently underwent a traumatic catheterization to relieve obstruction. The most common microorganisms are those associated with complicated UTI. Escherichia coli is most common, followed by Proteus mirabilis, Klebsiella pneumoniae and Pseudomonas aeruginosa.
2. Illustrative case A 74 year-old widow with long-term diabetes and dementia was referred to an emergency department from a nursing home because of progressive obtundation, fever and dyspnoea. She had been incontinent of urine and stool and managed for over 1 year with an indwelling urinary catheter. She had several prior hospitalizations for sepsis, dehydration and poorly controlled diabetes. She had been treated numerous times for febrile episodes with a variety of antibiotics including ampicillin and ciprofloxacin. The diabetes was managed with oral drugs. On physical examination she was a cachectic, semicomatose elderly woman. Her skin was dry and pale. An ammonia-like odour was noted. Her blood pressure was 70/50 mmHg, temperature 97 ◦ F (36.1 ◦ C), respiration 30 breaths/min, and pulse 120 beats/min and regular. There were no abnormal findings in the head, chest, abdomen or extremities. There were no localizing neurological signs. Her neck was supple. The urinary catheter was removed. It was heavily encrusted and virtually blocked. Laboratory findings included a white blood cell count of 16 000, with 85% polymorphonuclear leucocytes, 6% band neutrophils and 40% haematocrit. The serum sodium was 156 mmol/L, potassium 5.6 mmol/L, creatinine 3.5 mg/dL, blood urea nitrogen 68 mg/dL and glucose 420 mEq/dL. Blood pH was 7.1. Her urine was loaded with white blood cells; there were 4+ bacteria, leucocyte esterase (+), nitrite (+), and pH was 8. The urine culture was reported to contain >105 colony-forming units/mL of Providencia stuartii, Enterococcus faecalis and E. coli. Blood cultures obtained from two separate venous sites were positive for E. coli. The chest X-ray showed clear lung fields without cardiomegaly. Renal ultrasound showed a massively enlarged right kidney with echogenic focus in the right renal pelvis. She was treated with intravenous fluids, pressors, insulin and the antibiotics ‘du jour’ (those available at the time). The abscess was drained percutaneously, but the stone was not removed because of her high surgical risk. She survived a prolonged hospitalization complicated by arrhythmias, pulmonary emboli and an intravenous line infection. The microorganisms were temporarily eradicated from the urine, but multi-antibiotic resistant strains of P. stuartii together with Candida albicans re-emerged during therapy. She was
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Table 1 Key points about the use of indwelling catheters in nursing homes [1] • Indwelling catheters are used in ca. 7.5–10% of patients in many facilities • Lower rates are achieved by use of prompted voiding and incontinence pads • All patients catheterized for more than 1 month will have a urinary tract infection • Antibiotics are overused in nursing homes and are inappropriate 50% of the time • Multiresistant polymicrobial bacteriuria is common in catheterized patients • Bacteraemia is often silent; occurring in 10% of patients with a catheter change • Fever is uncommon, transient and low grade, but is an important finding • Urosepsis is a common cause for hospitalization • Silent pyelonephritis is present at autopsy in ca. one-third of patients • Catheter-associated infections are an independent risk factor for death Table 2 Complications of indwelling catheters [1] • Urinary tract infection • Acute pyelonephritis • Bacteraemia and sepsis • Formation of encrustations and obstruction to flow • Urethral strictures, prostatitis and orchitis • Acquisition and spread of yeasts and multiresistant bacteria • Increased mortality among bacteriuric patients with long-term catheters • Prolonged hospital stay • Increased costs for antimicrobial agents and management of sepsis • Late sequelae include metastatic osteomyelitis and meningitis
returned to the nursing home. She was found dead 30 days later. An autopsy was not performed.
3. Complications of indwelling catheters in the elderly This case illustrates several key points about the use of indwelling catheters in the elderly (Table 1) [1]. The complications of long-term use of indwelling catheters are summarized in Table 2 [1]. This case also illustrates the ‘blocker’ phenomenon [11] that occurs in patients colonized with ureasplitting microorganisms (Tables 3 and 4) [1]. The patient was managed according to the principles outlined in Table 5, but died 30 days after discharge. The outcome in this case is not surprising in view of the high post-hospital mortality noted in the Medicare study cited above [10]. Table 3 Major urease-producing microorganisms [1] • Proteus mirabilis, Proteus vulgaris • Providencia stuartii • Morganella morganii • Staphylococcus saprophyticus • Corynebacterium urealyticum • Mycoplasma urealyticum
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C.M. Kunin / International Journal of Antimicrobial Agents 28S (2006) S78–S81
Table 4 Sequential dangers of urease production • Hydrolyses urea to CO2 and NH3 • Alkalinizes the urine to >pH 8.0 • Forms precipitates of struvite crystal (Mg2 , NH4 , phosphate) • Obstructs urinary catheters • Forms infection stones • Produces urinary obstruction • Leads to persistent infection
The effects of long-term urinary catheterization among elderly patients in long-term nursing home facilities are usually less dramatic than in the illustrative case. Catheterassociated UTIs are rarely symptomatic [12]. We conducted a 1-year prospective study of 1540 nursing home patients in a stratified sample of extended care facilities in Columbus, Ohio [13]. The indwelling urinary catheter was found to be an independent risk factor for death. There was a linear relationship between duration of catheterization and death after adjustment for confounding factors including age, activities of daily living, cancer, heart disease, diabetes and decubitus ulcers (Table 6). Patients who were catheterized for 76% or more of their days in the nursing homes were three times more likely to die within 1 year. The number of hospitalizations, duration of hospitalization and use of antimicrobial drugs among this group were three times greater than among noncatheterized patients.
Table 5 Management of sepsis in catheterized patients • Clues are altered mental status, anorexia, low-grade fever and hypotension • Remove the catheter and inspect for encrustations and blockage • Do not insert a new catheter unless there is obstruction • Obtain blood and urine cultures; find out what antimicrobial drugs were used recently • Suspect urease-producing bacteria – Proteus, Providencia and Morganella – with blocked catheters and alkaline urine • Gram stain the urine to determine Gram-positive and Gram-negative bacteria and yeasts • Replete fluids and electrolytes and use pressor drugs as necessary • Obtain an ultrasound of the kidneys and bladder for obstruction and stones • Assume the patient is infected with several multiresistant uropathogens. E. coli has special epidemic virulence • Initiate presumptive therapy with an extended-spectrum penicillin, cephalosporin or fluoroquinolone with optional use of an aminoglycoside. Add drugs effective against enterococci and yeasts if Gram-positive cocci in chains or yeasts are seen in the urine • Simplify therapy to a single drug as soon as susceptibility data are available • The optimum duration of therapy is unknown, but need not exceed 1 week • Re-evaluate the need for an indwelling catheter
Table 6 Effect of duration of catheterization on mortality among 1540 nursing home patients observed for 1 year after adjustment for all other risk factors [13] Days (%)
Deaths (%)
Adjusted OR
None 1–25 26–75 78–100
16.4 23.7 35.8 43.6
1.00 1.35 2.09 2.99
OR, odds ratio. For all durations P < 0.01.
4. The need for renewed attention to the indwelling urinary catheter One would expect that prevention of catheter-associated infection would have a very high priority for government- and healthcare-industry-sponsored research. The Centers for Disease Control and Prevention (CDC) and hospitals continue to emphasize surveillance. This documents the problem, but does not provide solutions. The CDC guidelines for prevention of catheter-associated infections have not been updated since 1983 [14]. The National Institutes of Health sponsors a great deal of research focused on molecular mechanisms of sepsis, but not the cause. Most of the innovations in this field have come from the equipment manufacturers. There has been very little motivation for true innovation except for the relatively recent development of antimicrobial-impregnated catheters [15], conformable catheters [16] and novel methods to prevent catheter encrustations [17]. Catheters and drainage bag systems are considered to be a commodity competing for the lowest expenditures hospitals will support. There appears to be minimal oversight by the Food and Drug Administration. The only effective control is competition among manufacturers and the efforts of a small cadre of devoted clinical investigators. The mechanisms by which indwelling catheters produce infection are now well established. These consist initially of ascending colonization of the urine within the catheter lumen and eventually along the space between the urethra and catheter surface [1,15]. The technological requirements to design better catheters and drainage systems are fairly well known [18]. Dukes demonstrated the efficacy of closed drainage to block ascending infection in 1928 [19]. Disposable closed drainage systems became widely available almost 40 years ago [20]. None of the numerous attempts to improve the system have been shown to be more effective than simple closed drainage. Attempts to block the periurethral route by coating catheters with antimicrobial agents are currently receiving considerable attention. However, even if this were effective in the short term, they would be ineffective after the acquisition of bacteriuria in extended care settings. Catheters are fairly rigid structures. They drain the bladder, but block the urethra. The challenge is to produce an instrument that matches as closely as possible the normal physiological and mechanical characteristics of the voiding system. This requires construction of a thin-walled, continuously lubricated, collapsible (conformable) catheter to pro-
C.M. Kunin / International Journal of Antimicrobial Agents 28S (2006) S78–S81
tect the integrity of the urethra; a system to hold the catheter in place without a balloon; and to imitate the intermittent washing of the bladder urine. The efficacy of each component of the system will need to be evaluated in carefully conducted, controlled clinical trials. There is also a major need for better fitting male condom catheters and for external urine collection devices for incontinent females. Catheters of the future may be more expensive, but may be well worth the investment if used in the appropriate population. There is no need to wait for a mechanical or chemical answer to the problem of nosocomial UTIs. The culprit is unnecessary and prolonged use of catheters when these are no longer needed [21–23]. Improvements in catheter and drainage systems are welcome, but cannot substitute for thoughtful care. The major reasons for the use of indwelling urinary catheters in nursing homes are incontinence and management of decubitus ulcers. There are now several methods to deal with incontinence including prompted voiding, pharmacological agents and oestrogen therapy [24,25]. Hebel and Warren pointed out many years ago that ‘because urethral catheterization may be used as a management technique for decubitus ulcers, prevention of the latter may diminish the use of urethral catheters and their subsequent complications’ [26]. We must ask ourselves on daily rounds, ‘Is this catheter really necessary? When can I take it out? Are there alternative measures? Can a portable ultrasound help determine when a catheter may be required?’
Acknowledgment This article is based on a presentation at the 24th International Congress of Chemotherapy, held in Manila, The Philippines, 4–6 June 2005. The author has no conflicts of interest.
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