What is the recommended treatment for an inpatient with a urinary tract infection (UTI)?

Treatment of Inpatient Urinary Tract Infections

For inpatients with urinary tract infections (UTIs), the recommended empirical treatment is an intravenous third-generation cephalosporin, or a combination of amoxicillin plus an aminoglycoside, or a second-generation cephalosporin plus an aminoglycoside. 1

Classification and Initial Assessment

• UTIs in hospitalized patients are typically classified as complicated UTIs (cUTIs), which are more challenging to eradicate compared to uncomplicated infections 1

• Common factors associated with complicated UTIs include:

  • Obstruction at any site in the urinary tract 1
  • Foreign body presence (including urinary catheters) 1
  • Incomplete voiding or vesicoureteral reflux 1
  • Recent history of instrumentation 1
  • Male gender 1
  • Pregnancy, diabetes mellitus, or immunosuppression 1
  • Healthcare-associated infections 1
  • Presence of multidrug-resistant organisms 1

• Always obtain urine culture and susceptibility testing before initiating antibiotics to guide targeted therapy 1

Empirical Treatment Recommendations

First-line Options (Strong Recommendation)

• For patients with systemic symptoms:

  • An intravenous third-generation cephalosporin (e.g., ceftriaxone 1-2g daily) 1
  • OR amoxicillin plus an aminoglycoside (e.g., gentamicin 7.5 mg/kg/day divided every 8 hours) 1, 2
  • OR a second-generation cephalosporin plus an aminoglycoside 1

• For catheter-associated UTIs:

  • Similar regimens as above, with consideration of broader coverage due to higher risk of resistant organisms 1
  • Monitor for signs of systemic infection as CA-UTIs are the leading cause of secondary healthcare-associated bacteremia 1

Alternative Options

• Ciprofloxacin (400 mg IV twice daily) should only be used if:

  • Local resistance rate is <10% 1
  • The patient does not require hospitalization 1
  • The patient has anaphylaxis to β-lactam antimicrobials 1
  • The patient has not used fluoroquinolones in the last 6 months 1

• Cefepime (1-2g IV every 12 hours) for severe uncomplicated or complicated UTIs, particularly when Pseudomonas is suspected 3

Duration of Therapy

• Treatment for 7-14 days is generally recommended 1
• For male patients where prostatitis cannot be excluded, 14 days of treatment is recommended 1
• When the patient is hemodynamically stable and has been afebrile for at least 48 hours, a shorter treatment duration (e.g., 7 days) may be considered 1
• For gram-negative bacteremia from a urinary source, 7 days of treatment is recommended 1

Special Considerations

• Microbial spectrum: E. coli, Proteus spp., Klebsiella spp., Pseudomonas spp., Serratia spp., and Enterococcus spp. are the most common species found in cultures of cUTIs 1
• Antimicrobial resistance: Resistance is more likely in cUTIs compared to uncomplicated UTIs 1
• Underlying abnormalities: Appropriate management of any urological abnormality or underlying complicating factor is mandatory 1
• Avoid ceftriaxone monotherapy in patients with risk factors for enterococcal infections, as it may lead to enterococcal re-infections and prolonged hospitalization 4

Transition to Oral Therapy

• Once culture results are available and the patient shows clinical improvement, transition to an appropriate oral agent based on susceptibility testing 1
• Patients should be hemodynamically stable and able to retain oral medications before switching to oral therapy 1

Pitfalls and Caveats

• Do not use agents that are excreted in the urine but do not achieve therapeutic concentrations in the bloodstream (e.g., nitrofurantoin) for treating inpatient UTIs, as parenchymal and serum antimicrobial concentrations may be insufficient to treat pyelonephritis or urosepsis 1
• Fluoroquinolone use should be restricted due to increased rates of resistance and should not be used as first-line empiric treatment for complicated UTIs in patients from urology departments 1, 5
• For patients with indwelling catheters, a negative urinalysis can rule out CAUTI, but a positive urinalysis does not necessarily indicate infection due to its low specificity in catheterized patients 1
• Carbapenems and novel broad-spectrum antimicrobial agents should only be considered in patients with early culture results indicating the presence of multidrug-resistant organisms 1, 6

By following these evidence-based recommendations, clinicians can effectively manage inpatient UTIs while minimizing the risk of treatment failure and antimicrobial resistance.