Jeremy N. Reese, MD, MPH
Timothy D. Averch, MD, FACS
BASICS
DESCRIPTION
– Catheter-associated urinary tract infection (CAUTI/CA-UTI) is defined as an infection occurring in a person whose urinary tract is currently catheterized or has been catheterized within the previously 48 h.
– May refer to indwelling urethral or suprapubic catheters as well as routine intermittent catheter use.
• Catheter-associated asymptomatic bacteriuria (CA-ASB) is the presence of bacteria in the urinary tract without signs or symptoms of infection.
• CA-UTI and CA-ASB are often not distinguished from each other in reported cases of catheter associated bacteriuria and may result in inappropriate antibiotic use contributing to antimicrobial resistance and adverse event reporting to governmental agencies.
– UTIs are the most common type of healthcare-associated infection reported to the National Healthcare Safety Network (NHSN).
EPIDEMIOLOGY
Incidence
• CA-UTI is the most common nosocomial infection in the United States, accounting for 40% of hospital-acquired infections and over 80% of the 900,000 cases of bacteriuria annually.
• 15–25% of hospitalized patients have a urethral catheter inserted during their stay
• Incidence of CA-bacteriuria is thought to be 3–8% per catheter-day, with 3.1–7.4 CA-UTIs per 1000 urinary catheter days reported in US intensive care units
• Cost: $1006 per episode of CA-UTI
Prevalence
5–10% of long-term care facility patients are managed with indwelling or intermittent catheterization, accounting for >100,00 patients in the United States at any given time
RISK FACTORS
Duration of catheter use, placement outside operating room, open drainage system, female sex, diabetes mellitus, renal insufficiency, and inappropriate use (discussed below)
Genetics
N/A
PATHOPHYSIOLOGY
• Urethral catheterization is most important predisposing factor for nosocomial UTI
– Disrupted mucosa exposes new binding sites for bacteria allowing for growth of less virulent organisms
• Indwelling catheter may introduce bacteria at time of insertion, allowing ascension of uropathogens into bladder at time of insertion and then later via intra- and extra-luminal spread
– 2/3rd of identified pathogens are extraluminally acquired vs. 1/3rd intraluminally acquired
• Bacterial adhesions and production of exopolysaccharides allow for replication on the catheter surface and formation of biofilms
– Short-term catheter use tends to be associated with a single organism, whereas longer catheter use is associated with polymicrobial growth
– Biofilms protect bacteria from antimicrobials and host immune response, facilitating spread of antimicrobial resistance genes
• Escherichia coli is most common isolate, as well as Klebsiella, Serratia, Citrobacter, Enterobacter, Pseudomonas, Staphylococcus, and Enterococcus.
– Providencia, Morganella, and Proteus species more commonly isolated from long-term catheters
ASSOCIATED CONDITIONS
Spinal cord injury, neurogenic bladder, urinary incontinence, sacral or perineal wounds, prolonged immobilization
GENERAL PREVENTION
• Limiting use of urinary catheters, aseptic insertion, early discontinuation of catheter use, use of pre-sealed closed drainage systems, maintaining drainage bag below level of bladder (1)[A]
– Absolute indications include: urinary retention, accurate measurement of urine output in critically ill patients, prolonged general or spinal anesthetic, following selected urologic or gynecologic procedures, comfort care
• Application of institutional reminders such as nurse or electronic-based reminders, automatic stop-orders, use of reminder stickers or dated collection bags, requirement of physician order to place and maintain catheters
• No trials support use of: antimicrobial or chemical prophylaxis, routine catheter irrigation, antimicrobial use in drainage bag, antibiotic use at time of routine catheter exchange or removal
– Routine screening for CA-ASB should be avoided (1)[A]
• Alternatives to indwelling urethral catheters
– Condom catheters provide alternative to short-term catheter use in men with low-post void residuals
– Urethral and suprapubic catheters have similar rates of CA-UTI, although suprapubic catheters are often more comfortable, spare urethral catheterization, and are easier to exchange
– Intermittent catheterization significantly reduces rates of CA-ASB and is associated with higher patient satisfaction
• Healthcare providers should clean their hands with soap and water or use an alcohol-based hand rub before and after touching catheters.
• Avoid disconnecting the catheter and drain tube.
• The catheter is secured to the leg to prevent pulling on the catheter.
• Avoid twisting or kinking the catheter.
• Keep the bag lower than the bladder to prevent urine from backflowing to the bladder.
• Empty the bag regularly. The drainage spout should not touch anything while emptying the bag.
DIAGNOSIS
HISTORY
• CA-UTI: Patients with signs and symptoms of UTI with current or recent (<48 h) indwelling urinary catheter or routine intermittent catheter use
– Symptoms may include chills, rigors, altered mental status, malaise, flank pain, and pelvic discomfort
– Patients with a recently removed catheter may report dysuria, urinary urgency and/or frequency
– Spinal cord injury patients may report increased spasticity, autonomic dysreflexia and/or sense of uneasiness
PHYSICAL EXAM
• A few physical exam findings are reliable to diagnose CA-UTI but may include suprapubic and/or costovertebral angle tenderness, hematuria, or fever
• Foul-smelling and/or cloudy urine have not been shown to be significant clinical predictors of CA-UTI
– Encourage hydration if no other clinical indicators of infection and reassess thereafter
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• CA-UTI: Patients with signs and symptoms of UTI with current or recent (<48 h) indwelling urinary catheter or routine intermittent catheter use with cultures growing >103 cfu/mL (1)[A]
• CA-ASB is defined as cultures growing >105 cfu/mL WITHOUT signs or symptoms or UTI (1)[A]
• Urine specimen should be sent for culture prior to initiation of antimicrobials (1)[A]
• Catheters should be replaced, if still indicated, and a culture should obtained from newly placed catheter (1)[A]
• If catheter can be discontinued, a midstream voided specimen should be used for culture (1)[A]
• Pyuria on urinalysis is not sufficient to diagnose CA-UTI or CA-ASB, but its absence can exclude infection (1)[A]
Imaging
• Not routinely indicated
• May be necessary in cases of suspected complicated UTI such as concern for urolithiasis, foreign body, abscess, emphysematous infection, or vesicoureteral reflux
Diagnostic Procedures/Surgery
• Not routinely indicated
• Urodynamic studies may be useful to determine necessity of routine catheterization, particularly in spinal cord injury (SCI) population
• For patients with long-term catheter use (eg, SCI, neurogenic bladder population), routine cystoscopy has been suggested for cancer detection due to increased risk of both transitional cell and squamous-cell carcinomas
– Lifetime bladder malignancy incidence ranges from 0.39% to 2.4% in published retrospective reviews of SCI patients
Pathologic Findings
Pathology is not routinely performed
DIFFERENTIAL DIAGNOSIS
• In patients presenting with fever, rigors, altered mental status, and other non-specific symptoms, all other sources of infection must be ruled out as CA-ASB is diagnosed in >85% of patients with long-term catheter use
• Bladder tumor: Hematuria must be worked up, given increased risk of malignancy from long-term catheter use
• Bladder calculus: Associated with chronic urinary stasis
• Local inflammation: Vaginitis, urethritis, interstitial cystitis
TREATMENT
GENERAL MEASURES
• Prevention through early removal of urinary catheters is best preventative treatment
• Routine screening for and treatment of CA-ASB should be avoided (1)[A]
• Optimal duration of therapy is unknown, but typically ranges from 3 to 21 days depending on severity of symptoms (eg, cystitis, pyelonephritis, associated abscess, or bacteremia)
– Most literature suggests 7–14 days of therapy for CA-UTI (1)[A]
– 3-day regimen suggested in younger woman (<65 yr) in whom a catheter was recently removed (1)[B]
• Catheters placed >2 wk prior should be exchanged at time of diagnosis (prior to cultures being sent) to improve antimicrobial penetration and reduce bacterial concentrations (1)[A]
• When possible, antibiotic therapy should be culture driven to avoid exposure to additional antimicrobial agents
MEDICATION
First Line (2,3)
• Given incidence of polymicrobial colonization as well as involvement of both gram-positive and -negative organisms, no 1st-line agent can be recommended.
• Serious infections must be covered with broad-spectrum antibiotics and narrowed based on culture sensitivity patterns.
• Treatment of minor infections should be delayed until culture sensitivities are available to guide antimicrobial selection
Second Line
N/A
SURGERY/OTHER PROCEDURES
Rarely indicated, but may be necessary in cases of encrusted catheters, emphysematous, or abscess forming infections (see Section I: UTI, complex, adult)
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
N/A
Complementary & Alternative Therapies
• Antimicrobial coated catheters may delay detection of CA-ASB in short-term catheter use (<1 wk) (1)[B].
• Methenamine salts may reduce CA-ASB and CA-UTI in short-term catheter use (<1 wk) (1)[C].
• Cranberry products have not been shown to be effective in the prevention or treatment of infection in CA-UTI population (1)[A].
• Catheter irrigation has not been shown to prevent or treat CA-ASB or CA-UTI (1)[A].
ONGOING CARE
PROGNOSIS
• Generally good (4)
• Patient hospitalization lengths and costs are elevated when diagnosed with CA-ASB or CA-UTI
• Mortality rate among hospitalized patients with bacteremic UTI is ∼13%; however, <1% of CA-ASB results in bacteremia.
COMPLICATIONS
Patients with indwelling catheter experience increased rates of bacteremia, upper tract inflammation and infection, catheter obstruction, urinary stone formation, fistula formation, urethral erosion, incontinence, and bladder cancer
FOLLOW-UP
Patient Monitoring
• Institutional education on indications for catheter use and reminder systems for early catheter removal such as nursing protocols, electronic reminders, chart and collection bag stickers
• Attention to and staff education to urologically essential catheters (eg, radical prostatectomy, etc)
Patient Resources
Medline Plus: Catheter Related UTI. http://www.nlm.nih.gov/medlineplus/ency/article/000483.htm
REFERENCES
1. Hooten TM, Bradley SF, Cardenas DD, et al. Diagnosis, Prevention, and Treatment of Catheter-Associated Urinary Tract Infections in Adults: 2009 International Clinical Practice Guidelines from the Infectious Disease Society of America. Clin Infect Dis. 2010;50:625–663.
2. Tambyah PA, Oon J. Catheter-associated urinary tract infection. Curr Opin Infect Dis. 2012;25:365–370.
3. Conway LJ, Larson EL. Guidelines to prevent catheter-associated urinary tract infectiorn: 1980 to 2010. Heart & Lung. 2011;41:271–283.
4. Gould CV, Umscheid CA, Agarwal RK, et al. ; Healthcare Infection Control Practices Advisory Committee. Guideline for prevention of catheter-associated urinary tract infections 2009. Infect Control Hosp Epidemiol.2010;31:319–326.
ADDITIONAL READING
• CDC Health Care Associated Infections (HAIs) website: http://www.cdc.gov/HAI/ca_uti/uti.html
• Niel-Weise BS, van den Broek PJ, da Silva EM, et al. Urinary catheter policies for long-term bladder drainage. Cochrane Database Syst Rev. 2012;8:CD004201.
• Siddiq DM, Darouiche RO. New strategies to prevent catheter-associated urinary tract infections. Nat Rev Urol. 2012;9:305–314.
See Also (Topic, Algorithm, Media)
• Cystitis, General Considerations
• Pyelonephritis
• Urinary Tract Infection (UTI), Adult Female
• Urinary Tract Infection (UTI), Adult Male
• Urinary Tract Infection (UTI), Complicated, Adult
• Urinary Tract Infection (UTI), Pediatric
CODES
ICD9
• 041.49 Other and unspecified Escherichia coli [E. coli]
• 599.0 Urinary tract infection, site not specified
• 996.64 Infection and inflammatory reaction due to indwelling urinary catheter
ICD10
• B96.20 Unsp Escherichia coli as the cause of diseases classd elswhr
• N39.0 Urinary tract infection, site not specified
• T83.51XA Infect/inflm reaction due to indwell urinary catheter, init
CLINICAL/SURGICAL PEARLS
• Advise against routine screening for CA-ASB due to increasing antimicrobial resistance and inappropriate use.
• Most important prevention is adherence to indications for catheter use and prompt removal when no longer indicated.
• When catheter use is unavoidable, it should be aseptically inserted, maintained with closed drainage system and removed as early as possible.
• When infection is suspected, culture specimen should be sent from a newly placed catheter or midstream voided specimen.
• Treatment should be driven by culture sensitivities and typically last 7–14 days.