If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
Division of Infectious Diseases, Departments of Internal Medicine and Infection Control and Epidemiology, University of Michigan Health System, 3119 Taubman Center, 1500 East Medical Center Drive, Ann Arbor, MI 48109-5378, USA
Catheter-associated urinary tract infection (CAUTI) is common and costly and causes substantial patient morbidity, especially in the ICU setting.
•
CAUTI is often caused by hospital-based pathogens with a propensity toward antimicrobial resistance.
•
Duration of urinary catheterization is the predominant risk for CAUTI; preventive measures directed at limiting placement and early removal of urinary catheters significantly improve CAUTI rates.
•
Intervention bundles, collaboratives, and hospital leadership are powerful tools for implementing preventive measures for healthcare-associated infections, including CAUTI.
Introduction: magnitude of the problem
Healthcare-associated urinary tract infections (UTIs) account for up to 40% of infections in hospitals and 23% of infections in the intensive care unit (ICU).
The vast majority of UTIs are related to indwelling urinary catheters; approximately 70% of UTIs (and 95% of UTIs occurring in ICUs) develop in patients with urinary catheters.
The Centers for Disease Control and Prevention (CDC) estimated that in 2007, 139,000 CAUTIs occurred in US hospitals.
CAUTI has significant clinical and economic consequences. Catheter-associated bacteriuria may be associated with excess mortality, even after controlling for underlying factors such as severity of illness and comorbidities; hospital-onset bloodstream infection resulting from a urinary source has a case fatality of 32.8%.
The financial implication for hospitals is underscored by the fact that since October 2008, the Centers for Medicare and Medicaid Services (CMS) no longer reimburses hospitals for the extra costs of managing a patient with hospital-acquired CAUTI.
This article reviews the pathogenesis and epidemiology of CAUTI, with a focus on preventive measures for CAUTI among the critically ill.
Pathogenesis
Urinary catheters interfere with the normal innate defense mechanisms that prevent attachment and migration of pathogens into the bladder; these mechanisms include length of the urethra and micturition.
Biofilms, composed of clusters of microorganisms and extracellular matrix (primarily polysaccharide materials), form on both the internal lumen and external surfaces of urinary catheters.
Typically, the biofilm is composed of one type of microorganism, although polymicrobial biofilms are possible. Organisms in the biofilm grow slower than those in urine, and yet microorganisms in the biofilm may ascend the catheter in 1 to 3 days.
Microorganisms, such as Proteus sp, have the ability to hydrolyze urea in the biofilm and increase urinary pH. As a result, minerals may precipitate, causing mineral encrustations along the catheter or renal calculi. Biofilms are also important because they provide a protective environment from immune cells. Antimicrobials penetrate into biofilms poorly, and microorganisms grow more slowly in biofilms, decreasing the effects of many antimicrobials.
Most microorganisms causing CAUTI enter the bladder by ascending the urethra from the perineum. Usually (66% of the time), organisms migrate in the biofilm on the external surface of the catheter. These organisms are primarily endogenous organisms colonizing the patient's intestinal tract and perineum.
A smaller proportion of infections (34%) are acquired from intraluminal contamination of the collection system from exogenous sources, resulting from cross-transmission of organisms from the hands of healthcare personnel.
Rarely, organisms such as Staphylococcus aureus cause upper UTI from hematogenous spread.
In most instances, CAUTI is caused by microorganisms from the patient's own gastrointestinal tract; however, approximately 15% of episodes of health-care-associated bacteriuria occur in clusters because of intrahospital transmission from one patient to another.
Most of these hospital-based outbreaks have been associated with improper hand hygiene of healthcare personnel.
Epidemiology of catheter-associated urinary tract infections
CAUTIs make up approximately 40% of all hospital-acquired infections, but they account for a smaller proportion of healthcare-associated infections in the ICU setting. With interventions occurring across the country, rates of CAUTI in ICUs declined significantly between 1990 and 2007.
Rates of CAUTIs reported through the National Healthcare Safety Network (NHSN) in 2010 ranged from 4.7 infections per 1000 catheter-days in burn ICUs to 1.3 infections per 1000 catheter-days in medical/surgical ICUs.
CAUTIs in pediatric ICUs occur at a rate of 2.2 to 3.9 UTIs per 1000 catheter-days. General care wards have rates of CAUTI equivalent to or higher than in the ICU setting, ranging from 0.2 to 3.2 per 1000 catheter-days; the highest rates occur in rehabilitation units.
Enterobacteriaceae are the most common pathogens associated with CAUTI, but in the ICU setting, Candida sp (18%), Enterococcus sp (10%), and Pseudomonas aeruginosa (9%) become more prevalent.
In addition, antimicrobial resistance in CAUTI isolates from patients in ICU has risen in recent decades. In data reported from the CDC's NHSN in 2006 to 2007, 24.8% of all Escherichia coli isolates from patients with CAUTIs were resistant to fluoroquinolones.
NHSN annual update: antimicrobial-resistant pathogens associated with healthcare-associated infections: annual summary of data reported to the National Healthcare Safety Network at the Centers for Disease Control and Prevention, 2006-2007.
Many members of Enterobacteriaceae produced extended-spectrum β-lactamases; 21.2% of Klebsiella pneumoniae and 5.5% of E. coli isolates from patients with CAUTIs were resistant to ceftriaxone or ceftazidime. Even more concerning is that during this same time, 10.1% of all K. pneumoniae isolates from patients with CAUTIs were resistant to carbapenems.
NHSN annual update: antimicrobial-resistant pathogens associated with healthcare-associated infections: annual summary of data reported to the National Healthcare Safety Network at the Centers for Disease Control and Prevention, 2006-2007.
Bacteriuria, the precursor to CAUTI, develops quickly at an average daily rate of 3% to 10% per day of catheterization. Almost 26% of patients with a catheter in place for 2 to 10 days develop bacteriuria, and virtually all patients catheterized for 1 month develop bacteriuria. Hence, catheterization for greater than 1 month is generally the definition for long-term catheterization.
Box 1 outlines the major risk factors for CAUTI. Females have a higher risk of bacteriuria than males, and heavy bacterial colonization of the perineum increases this risk. Other patient factors identified in one or more studies include rapidly fatal underlying illness, age greater than 50 years, nonsurgical disease, hospitalization in an orthopedic or urological service, catheter insertion after the sixth day of hospitalization, catheter inserted outside the operating room, diabetes mellitus, and serum creatinine level greater than 2 mg/dL at the time of catheterization. Nonadherence to aseptic catheter care recommendations have been associated with increased risk of bacteriuria, whereas systemic antimicrobial agents have a protective effect on bacteriuria (relative risk = 2.0–3.9).
Risk factors associated with catheter-associated urinary tract infection
Nonmodifiable, patient-level risk factors
Female sex
Severe underlying illness
Nonsurgical disease
Age greater than 50 years
Diabetes mellitus
Serum creatinine level greater than 2 mg/dL
Modifiable risk factors
Duration of catheterization
Adherence to aseptic catheter care
Catheter insertion after the sixth day of hospitalization
Catheter insertion outside the operating room
Risk factors for UTI-associated bacteremia are less clearly understood than for catheter-associated bacteriuria because catheter-associated bacteremia occurs in less than 4% of infections. Risk factors for bloodstream infections from a urinary source from early studies included infections due to Serratia marcescens, male sex, immunosuppressant therapy, history of malignancy, cigarette use in the past 5 years, and number of hospital-days before bacteriuria.
These predictors for hospital-onset urinary-tract-related bloodstream infection should aid in implementing appropriate preventive practices in patients at highest risk.
Surveillance for catheter-associated urinary tract infections
Clinical diagnosis of CAUTI remains challenging, as neither pyuria nor bacteriuria is a reliable indicator of symptomatic UTI in the setting of catheterization.
The term, bacteriuria, is often used interchangeably with UTI in the published literature, as many early studies used bacteriuria to define catheter-associated infection. However, the distinction is clinically important because asymptomatic catheter-associated bacteriuria rarely results in adverse outcomes and generally does not require treatment.
Diagnosis of UTI in patients with long-term urinary catheters is particularly problematic because bacteriuria is universally present unless antimicrobial therapy is given. Fever or other systemic symptoms may be the only clinical indication of UTI, especially in patients who have spinal cord injuries.
Clinical recognition of UTI remains important because a large proportion of antimicrobials in hospitalized patients is prescribed for treatment of UTI, most often asymptomatic bacteruria.
An essential element of any preventive program is to measure the prevalence of the condition and provide feedback of the results of interventions to the clinical care providers. The NHSN surveillance definition for healthcare-associated UTI allows for standardization and interhospital comparison of infection rates.
Centers of Disease Control and Prevention. NHSN manual: patient safety component protocols. Available at: http://www.cdc.gov/nhsn/TOC_PSCManual.html. Accessed July 23, 2012.
The NHSN symptomatic CAUTI rate (UTI per 1000 urinary catheter-days) is the most widely accepted measure of infection surveillance and is endorsed by the CDC, Infectious Diseases Society of America, Society for Healthcare Epidemiologists of America (IDSA-SHEA) compendium, and Association for Professionals in Infection Control and Epidemiology (APIC).
However, a population-based measure, in which 10,000 patient-days is used as the denominator, may be a better measure to assess quality improvement interventions at individual hospitals.
Surveillance for CAUTI was not a priority for most hospitals earlier, perhaps due to lack of resources required to perform full hospital surveillance and the low priority given to CAUTI, as compared with other healthcare-associated infections.
Hospital-acquired catheter-associated urinary tract infection: documentation and coding issues may reduce financial impact of Medicare’s new payment policy.
In addition, beginning in 2012, CMS has required, as a condition of participation, that hospitals submit ICU-level CAUTI rates to NHSN. Other process or proxy measures, such as rates of asymptomatic bacteriuria, percentage of patients with indwelling catheters, percentage of catheterization with accepted indications, and duration of catheter use, have been used in studies and collaboratives with good success.
General strategies are formulated for prevention of all healthcare-associated infections, whereas targeted strategies are focused at risk factors specific for CAUTI (Box 2).
Guideline for hand hygiene in health-care settings. recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA hand hygiene task force. Society for Healthcare Epidemiology of America/Association for Professionals in Infection Control/Infectious Diseases Society of America.
Most outbreaks of urinary pathogens have been linked to inadequate employee hand hygiene. The urinary tract of hospitalized patients, especially those in an ICU setting, represents a significant reservoir for multidrug-resistant organisms (MDRO). Indwelling devices, including urinary catheters, increase the risk of colonization with MDRO, and therefore, limiting their use is an important strategy for prevention of MDRO.
Reduction in use of broad-spectrum antimicrobials, as part of an overall antimicrobial stewardship program, is an important strategy to prevent development of antimicrobial resistance related to urinary catheters.
Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America guidelines for developing an institutional program to enhance antimicrobial stewardship.
Repeated antimicrobial treatment of bacteriuria during long-term catheterization is a significant risk for colonization with MDRO, yet some of this use may be inappropriate.
A recent study revealed that a 1-hour educational session reduced the inappropriate use of antibiotic therapy for inpatients with urine cultures positive for MDRO.
Does an educational session with an infectious diseases physician reduce the use of inappropriate antibiotic therapy for inpatients with positive urine culture results? A controlled before-and-after study.
A hospital-site controlled intervention using audit and feedback to implement guidelines concerning inappropriate treatment of catheter-associated asymptomatic bacteriuria.
Nevertheless, a 2005 nationwide survey identified that more than one-half of hospitals did not have a system for monitoring urinary catheters, three-quarters did not monitor duration of catheterization, and one-third did not conduct any surveillance for UTIs.
Surprisingly, even after enactment of the CMS nonpayment rule, in 2009, only 1 CAUTI prevention practice, use of bladder ultrasonography, was used in more than 50% of hospitals.
Even when focusing on ICUs, where the risk of CAUTI is highest, only a small proportion of ICUs have policies supporting bladder ultrasonography (26%), catheter removal reminders (12%), or nurse-initiated catheter discontinuation.
The collaborative approach to implementation of prevention measures, as detailed later, has begun to systematic changes in adoption of prevention practices.
Hospital-acquired catheter-associated urinary tract infection: documentation and coding issues may reduce financial impact of Medicare’s new payment policy.
Indwelling urinary catheters are the primary risk factor for healthcare-associated UTIs, therefore, the most effective strategy for CAUTI prevention is limitation or avoidance of catheterization.
Catheter use rates vary by ICU type but range from 0.16 urinary catheter-days per patient-days in pediatric medical ICUs to 0.80 urinary catheter-days per patient-days in trauma ICUs.
The first step toward decreasing catheter use is limiting placement of indwelling urinary catheters; catheters should be inserted only for appropriate indications (see Box 3). Despite these recommendations, studies indicate that urinary catheters are placed for inappropriate indications in 21% to 50% of catheterized patients.
Healthcare institutions should develop written policies and criteria for indwelling urinary catheterization based on these widely accepted indications.
Physician orders should be required for insertion of any urinary catheter, and institutions should implement a system for documenting placement of catheters.
Interventions for limiting placement of urinary catheter targeted at hospital locations where initial placement usually occurs, such as emergency departments and operating rooms, have the most impact.
A multifaceted approach including several types of education, system redesign, rewards, and feedback managed by a dedicated nurse resulted in a marked decrease in daily prevalence of urinary catheter-days.
Once catheters are placed, strategies for early removal become essential. Urinary catheter management based on physicians' orders alone may be inadequate because physicians are frequently unaware that their patient has a urinary catheter. In one study, 28% of physicians were unaware that their patient had a catheter, with the lack of awareness increasing with the level of training.
A nurse-based reminder to physicians to remove unnecessary urinary catheters in a Taiwanese hospital resulted in a reduction in CAUTI from 11.5 to 8.3 per 1000 catheter-days.
Such interventions are easy to implement and may consist of either a written notice or a verbal contact with the physician regarding the presence of a urinary catheter and alternative options. The feasibility of this type of intervention was demonstrated in a statewide effort that resulted in significant decrease in catheter use and increase in appropriate indications of catheters.
However, computerized physician order entry systems may offer a more cost-effective and efficient system to reduce both placement of catheters and duration of catheterization. Cornia and colleagues
found that a computerized reminder reduced the duration of catheterization by 3 days. A systematic review and meta-analysis reports that urinary catheter reminder systems and stop orders seem to reduce the mean duration of catheterization by 37% and CAUTI by 52%.
Systematic review and meta-analysis: reminder systems to reduce catheter-associated urinary tract infections and urinary catheter use in hospitalized patients.
In reality, the actual number of CAUTIs decreased, but because of a decline in the denominator (catheter-days), the rate increased. This observation has led some experts to recommend that the rate of UTI per 10,000 patient-days be used as a more appropriate outcome measure for quality improvement interventions surrounding urinary catheters.
Specific protocols for the management of postoperative urinary catheters are important for reducing urinary catheterization use. CMS has now included removal of urinary catheters within 24 hours of surgery as one of the Surgical Care Improvement Project (SCIP) measures that are reported by all hospitals.
Approximately, 85% of patients admitted for major surgical procedures had perioperative indwelling catheters; patients with duration of catheterization greater than 2 days were significantly more likely to develop UTIs and were less likely to be discharged home.
Older surgical patients were particularly at risk for prolonged catheterization; 23% of surgical patients older than 65 years were discharged to skilled nursing facilities with an indwelling catheter in place and were substantially more likely to have rehospitalization or death within 30 days.
In a large prospective trial of patients undergoing orthopedic procedures, a multifaceted protocol for perioperative catheter management resulted in a two-thirds reduction in the incidence of UTI. The protocol consisted of limiting catheterization to surgeries longer than 5 hours or to total hip and knee replacements, removal of urinary catheters on postoperative day 1 after total knee arthroplasty, and postoperative day 2 after total hip arthroplasty.
This group has significance because it is at risk of requiring recatheterization (see Fig. 1). Patients who developed postoperative retention were more likely to be older men, undergoing knee, hip, or colon surgery. It will be important to focus future studies on interventions to prevent urinary retention in this higher-risk group.
Alternatives to indwelling urinary catheters
Compared with indwelling urinary catheterization, intermittent urinary catheterization reduces the risk of bacteriuria and UTI. Patients with neurogenic bladder and long-term urinary catheters, in particular, may benefit from intermittent catheterization.
A recent meta-analysis reported a reduced risk of asymptomatic and symptomatic bacteriuria with the use of intermittent catheterization in patients after hip or knee surgery compared with indwelling catheterization.
Alternatively, condom catheters may be considered in place of indwelling catheters in appropriately selected male patients without urinary retention or bladder outlet obstruction. A randomized trial demonstrated a decrease in bacteriuria, symptomatic UTI, or death in patients with condom catheters, when compared with those with indwelling catheters; the benefit was primarily seen in men without dementia.
Aseptic techniques for insertion and maintenance of urinary catheters
If urinary catheterization is necessary, aseptic catheter insertion and maintenance is essential for prevention of CAUTI. Urinary catheters should be inserted by a trained healthcare professional using aseptic technique.
Cleaning the meatus before catheter insertion is recommended, but ongoing daily meatal cleaning using an antiseptic has not shown clear benefit and may increase rates of bacteriuria compared with routine care with soap and water.
Closed urinary catheter collection systems reduce the risk of CAUTI and have been the standard of care in the United States for many years. Opening the closed system should be avoided; sampling urine may be performed aseptically from a port or from the drainage bag when large samples are required.
Prophylactic instillation of antiseptic agents or irrigation of the bladder with antimicrobial or antiseptic agents has been shown to increase infection and is not recommended.
Reduction in bacteriuria associated with exchange of catheters is only transient, therefore routine exchange of urinary catheters is not recommended, except for mechanical reasons.
Antimicrobial catheters are typically coated with nitrofurazone, minocycline, or rifampin, but other agents are being evaluated in newer catheters.
In a large meta-analysis, silver alloy catheters were found to significantly reduce the incidence of asymptomatic bacteriuria in adult patients catheterized for less than 7 days, but the effect was diminished in those catheterized for greater than 7 days.
Similarly, antibiotic-impregnated catheters were found to decrease the rate of asymptomatic bacteriuria in those catheterized for less than 7 days but demonstrated no benefit when the duration of catheterization was greater than 7 days.
Few studies have evaluated antiseptic-coated and antibiotic-coated catheters in long-term urinary catheterization; thus, no conclusion can be drawn on use of anti-infective catheters in this setting.
The use of anti-infective catheters may be considered when the rates of CAUTI remain persistently high despite adherence to other evidence-based practices or in patients deemed to be at high risk for CAUTI or its complications.
Despite the fact that anti-infective urinary catheters seem to reduce bacteriuria in patients with short-term urinary catheterization, there is no convincing evidence that use of these catheters prevents CAUTI, UTI-related bloodstream infection, or mortality. Therefore, there is no recommendation for routine use of anti-infective urinary catheters to prevent CAUTI.
A national mixed-methods study revealed that in 2009, 45% of nonfederal and 22% of Veteran Affairs hospitals used antimicrobial catheters; hospitals using anti-infective catheters often based their decisions on hospital-specific pilot studies.
However, because of issues of cost, potential adverse effects, and possible selection for MDRO, systemic antimicrobial therapy specifically for the purpose of preventing CAUTI is not recommended.
Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America guidelines for developing an institutional program to enhance antimicrobial stewardship.
Implementation: the role of bundles and collaboratives
Recently, “bundles” of interventions have been used with resounding success for prevention of several types of healthcare-associated infections. An example of a bundle applied to CAUTI prevention is the memory aide “ABCDE” outlined in Box 4.
Finally, the important role of local hospital leadership and followership for ensuring effective implementation of preventive initiatives has recently been highlighted.
The “ABCDE” for preventing catheter-associated urinary tract infection
•
Adherence to general infection control principles (eg, hand hygiene, surveillance and feedback, aseptic insertion, proper maintenance, education) is important.
•
Bladder ultrasound may avoid indwelling catheterization.
•
Condom catheters or other alternatives to an indwelling catheter such as intermittent catheterization should be considered in appropriate patients.
•
Do not use the indwelling catheter unless you must!
•
Early removal of the catheter using a reminder or nurse-initiated removal protocol appears warranted.
Summary
CAUTIs are common, costly, and cause significant patient morbidity, especially in the ICU setting. CAUTIs are associated with hospital pathogens with a high propensity toward antimicrobial resistance. Despite studies showing benefit of interventions for prevention on CAUTI, many US healthcare facilities have not adopted these practices. Duration of urinary catheterization is the predominant risk for CAUTI; preventive measures directed at limiting placement and early removal of urinary catheters have a significant impact on decreasing CAUTI. Intervention bundles, collaboratives, and hospital leadership are powerful tools for implementation of preventive measures for healthcare-associated infections, including CAUTI.
CAUTIs account for approximately 40% of all healthcare-associated infections. As urinary catheters account for most healthcare-associated UTIs, the most important interventions are directed at avoiding placement of urinary catheters and promoting early removal when appropriate. Alternatives to indwelling catheters such as intermittent catheterization and condom catheters should be considered. If indwelling catheterization is appropriate, proper aseptic practices for catheter insertion and maintenance and a closed catheter collection system is essential for prevention of CAUTI. The use of anti-infective catheters may also be considered when the rates of CAUTI remain persistently high despite adherence to other evidence-based practices or in patients deemed to be at high risk for CAUTI or its complications. Attention toward prevention of CAUTI will likely increase because CMS and other third-party payers no longer reimburse for hospital-acquired UTIs.
NHSN annual update: antimicrobial-resistant pathogens associated with healthcare-associated infections: annual summary of data reported to the National Healthcare Safety Network at the Centers for Disease Control and Prevention, 2006-2007.
Centers of Disease Control and Prevention. NHSN manual: patient safety component protocols. Available at: http://www.cdc.gov/nhsn/TOC_PSCManual.html. Accessed July 23, 2012.
Hospital-acquired catheter-associated urinary tract infection: documentation and coding issues may reduce financial impact of Medicare’s new payment policy.
Guideline for hand hygiene in health-care settings. recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA hand hygiene task force. Society for Healthcare Epidemiology of America/Association for Professionals in Infection Control/Infectious Diseases Society of America.
Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America guidelines for developing an institutional program to enhance antimicrobial stewardship.
Does an educational session with an infectious diseases physician reduce the use of inappropriate antibiotic therapy for inpatients with positive urine culture results? A controlled before-and-after study.
A hospital-site controlled intervention using audit and feedback to implement guidelines concerning inappropriate treatment of catheter-associated asymptomatic bacteriuria.
Systematic review and meta-analysis: reminder systems to reduce catheter-associated urinary tract infections and urinary catheter use in hospitalized patients.
Disclosures: C.E.C.—none and S.S.—honoraria and speaking fees from academic medical centers, hospitals, specialty societies, state-based hospital associations, and nonprofit foundations (eg, Michigan Health and Hospital Association, Institute for Healthcare Improvement) for lectures about catheter-associated urinary tract infection.
00082-6&id=gr1.jpg){kind=link}