What is the definition and treatment of a complicated Urinary Tract Infection (UTI)?

From the Guidelines

A complicated urinary tract infection (UTI) is an infection that occurs in the presence of structural or functional abnormalities of the urinary tract, or in patients with underlying conditions that increase the risk of treatment failure or serious complications, and should be treated with empiric broad-spectrum antibiotics initially, followed by targeted therapy based on culture results, with a treatment duration of 7-14 days depending on severity, as recommended by the European Association of Urology guidelines 1. The definition of a complicated UTI includes infections that occur in patients with underlying conditions such as pregnancy, male gender, elderly patients, immunosuppression, diabetes, recent urinary tract instrumentation, indwelling catheters, renal insufficiency, or anatomical abnormalities.

• Key factors that contribute to the complexity of UTIs include:
  • Underlying structural or functional abnormalities of the urinary tract
  • Presence of underlying medical conditions that increase the risk of treatment failure or serious complications
  • Recent urinary tract instrumentation or indwelling catheters
  • Anatomical abnormalities such as cystoceles, bladder or urethral diverticula, fistulae, or urinary tract obstruction
• Treatment of complicated UTIs typically involves:
  • Empiric broad-spectrum antibiotics initially, such as fluoroquinolones (ciprofloxacin 400mg every 12 hours), third-generation cephalosporins (ceftriaxone 1-2g daily), or piperacillin-tazobactam (3.375g every 6 hours) for hospitalized patients
  • Targeted therapy based on culture results, with oral options including fluoroquinolones (ciprofloxacin 500mg twice daily), trimethoprim-sulfamethoxazole (160/800mg twice daily), or amoxicillin-clavulanate (875/125mg twice daily) for outpatient treatment
  • A treatment duration of 7-14 days depending on severity, as recommended by the European Association of Urology guidelines 1
• It is also important to address underlying anatomical or functional abnormalities to prevent recurrence, which might involve removing obstructions, managing diabetes, or replacing long-term catheters, as highlighted in the study by 1.
• Additionally, patients should increase fluid intake, complete the full antibiotic course even if symptoms improve, and follow up to ensure resolution, as recommended by the study 1.
• The European Association of Urology guidelines 1 provide strong recommendations for the treatment of complicated UTIs, including the use of a combination of antibiotics and the management of any urological abnormality and/or underlying complicating factors.
• The study by 1 also highlights the importance of considering the duration of treatment, with short-duration courses being appropriate for the management of complicated UTI and pyelonephritis, with appropriate diagnosis based on clinical response.
• Overall, the treatment of complicated UTIs requires a comprehensive approach that takes into account the underlying causes of the infection, the severity of the infection, and the need to prevent recurrence, as recommended by the European Association of Urology guidelines 1 and supported by the studies 1, 1.

From the FDA Drug Label

1.9 Complicated Urinary Tract Infections: 5 Day Treatment Regimen Levofloxacin tablets are indicated for the treatment of complicated urinary tract infections due to Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis 1.10 Complicated Urinary Tract Infections: 10 Day Treatment Regimen Levofloxacin tablets are indicated for the treatment of complicated urinary tract infections (mild to moderate) due to Enterococcus faecalis, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, or Pseudomonas aeruginosa

Definition of Complicated UTI: A complicated UTI is defined as a urinary tract infection that occurs in patients with an underlying condition that increases the risk of treatment failure, such as:

• Underlying renal diseases or conditions, like complete obstruction, surgery, transplantation, or congenital malformation.
• Concurrent infection.
• A UTI that is caused by a resistant pathogen.

Treatment of Complicated UTI: The treatment of complicated UTI typically involves the use of antibiotics, such as levofloxacin, for a duration of 5 to 10 days, depending on the severity of the infection and the causative pathogen.

• The 5-day treatment regimen is indicated for complicated UTIs due to Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis.
• The 10-day treatment regimen is indicated for complicated UTIs (mild to moderate) due to Enterococcus faecalis, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, or Pseudomonas aeruginosa. The choice of antibiotic and duration of treatment should be based on the results of culture and susceptibility testing, as well as the patient's clinical response to treatment 2.

From the Research

Definition of Complicated UTI

• A complicated Urinary Tract Infection (UTI) is defined as an infection that occurs in a patient with a structural or functional abnormality impeding urine flow, or in a host with altered defences 3.
• It can also be described as an infection that occurs in individuals with functional or structural abnormalities of the genitourinary tract 4.
• A complicated UTI is characterized by the presence of underlying abnormalities, such as anatomical abnormalities or significant medical or surgical comorbidities, which can increase the risk of infection and treatment failure 5.

Treatment of Complicated UTI

• The treatment of complicated UTIs often requires a prolonged course of antimicrobial therapy, and may need to be complemented with endoscopic and/or surgical intervention 3.
• The choice of antimicrobial regimen is determined by clinical presentation, patient tolerance, renal function, and known or anticipated infecting organisms 4.
• Levofloxacin is a fluoroquinolone antibacterial that has been used to treat complicated UTIs and pyelonephritis, but its use has been limited due to the emergence of fluoroquinolone resistance 6.
• Other antibiotics, such as ceftriaxone, may also be used to treat complicated UTIs, but their use can be associated with an increased risk of enterococcal re-infection and prolonged hospitalization 7.

Key Considerations

• The management of complicated UTIs is individualized depending on patient variables and the infecting organism 4.
• It is essential to collect a urine specimen for culture before antimicrobial therapy and to characterize the underlying genitourinary abnormality 4.
• Asymptomatic bacteriuria should not be treated except before an invasive genitourinary procedure 4.
• The treatment outcome and risk of complications can vary depending on the choice of antibiotic therapy and the presence of underlying abnormalities 7.