What is the recommended management for complicated Urinary Tract Infections (UTI)?

Management of Complicated Urinary Tract Infections

For complicated UTIs, obtain a urine culture before initiating empiric antibiotics, address any underlying urological abnormalities, and treat for 7-14 days (14 days for men when prostatitis cannot be excluded) with regimens targeting multidrug-resistant organisms based on local resistance patterns. 1, 2

Defining Complicated UTI

Complicated UTIs occur when specific host or anatomic factors make infection harder to eradicate compared to uncomplicated infections. 1 Key defining factors include:

• Obstruction at any site in the urinary tract 1
• Foreign body (including catheters) 1
• Incomplete voiding or vesicoureteral reflux 1
• UTI in males (always considered complicated) 1, 3
• Recent instrumentation 1
• Pregnancy, diabetes mellitus, or immunosuppression 1
• Healthcare-associated infections 1
• ESBL-producing or multidrug-resistant organisms isolated 1, 2

The microbial spectrum is broader than uncomplicated UTIs, with E. coli, Proteus spp., Klebsiella spp., Pseudomonas spp., Serratia spp., and Enterococcus spp. being most common, and antimicrobial resistance is more likely. 1, 2

Initial Management Steps

Always obtain urine culture and susceptibility testing before starting antibiotics to guide targeted therapy. 1, 2 This is critical because failing to obtain pre-treatment cultures complicates management if empiric therapy fails. 3

Address the underlying urological abnormality or complicating factor—this is mandatory for successful treatment. 1 Optimal antimicrobial therapy alone is insufficient without correcting anatomic or functional problems.

Empiric Antibiotic Selection

First-Line Parenteral Options (for severe illness or hemodynamic instability):

• Carbapenems: Imipenem/cilastatin 0.5g three times daily, meropenem 1g three times daily, or meropenem-vaborbactam 2g three times daily 2
• Newer β-lactam/β-lactamase inhibitor combinations: Ceftolozane/tazobactam 1.5g three times daily, ceftazidime/avibactam 2.5g three times daily, or cefiderocol 2g three times daily 2
• Aminoglycosides: Gentamicin 5mg/kg once daily, amikacin 15mg/kg once daily, or plazomicin 15mg/kg once daily (especially with prior fluoroquinolone resistance) 2
• Ceftriaxone 2g daily: Appropriate as initial long-acting parenteral antimicrobial with excellent urinary concentrations 2

Oral Step-Down Options (when clinically improved):

• Fluoroquinolones (only if local resistance <10%): Ciprofloxacin 500-750mg twice daily for 7 days or levofloxacin 750mg once daily for 5 days 1, 2, 4, 5
• Trimethoprim-sulfamethoxazole: 160/800mg twice daily for 14 days 1, 2, 4
• Oral cephalosporins: Cefpodoxime 200mg twice daily for 10 days, ceftibuten 400mg once daily for 10 days, or cefuroxime 500mg twice daily for 10-14 days 1, 2

If using oral agents empirically, administer an initial intravenous dose of a long-acting parenteral antimicrobial (e.g., ceftriaxone) first. 1

Treatment Duration

Standard duration is 7-14 days, with specific considerations: 1, 2

• 14 days for men when prostatitis cannot be excluded (which is often the case in initial presentations) 1, 3, 2
• 7 days may be considered when the patient is hemodynamically stable and has been afebrile for at least 48 hours 1, 2
• However, recent evidence shows 7-day ciprofloxacin was inferior to 14-day therapy for short-duration clinical cure in men with complicated UTI (86% vs. 98%) 3

Duration should be closely related to treatment of the underlying abnormality. 1

Tailoring Therapy Based on Culture Results

Once culture and susceptibility results are available:

• If organism is susceptible to current therapy: Continue to complete appropriate duration 2
• If organism shows resistance: Switch to appropriate agent based on sensitivities 2
• For multidrug-resistant organisms: Consider ceftazidime-avibactam 2.5g three times daily or meropenem-vaborbactam 2g three times daily for 14 days 3

Special Considerations for Catheter-Associated UTI

• Replace indwelling catheters that have been in place ≥2 weeks at onset of treatment to hasten symptom resolution and reduce recurrence risk 2
• Remove urinary catheters as soon as clinically appropriate to reduce infection risk 2
• Do not treat asymptomatic bacteriuria in catheterized patients as this leads to inappropriate antimicrobial use and resistance 2

Monitoring and Follow-Up

• Reassess patients at 72 hours if no clinical improvement with defervescence 2
• Extended treatment and urologic evaluation may be needed for delayed response 2
• Obtain follow-up urine culture after completion of therapy to ensure resolution of infection 2

Critical Pitfalls to Avoid

• Failing to obtain urine culture before initiating antibiotics complicates management if empiric therapy is ineffective 3
• Using fluoroquinolones when other effective options are available, especially given resistance concerns 3
• Inadequate treatment duration can lead to persistent or recurrent infection, particularly if prostate involvement is present 3
• Ignoring underlying urological abnormalities that contribute to infection or recurrence 3
• Failing to replace long-term catheters at treatment initiation can reduce treatment efficacy 2
• Using moxifloxacin for UTI treatment due to uncertainty regarding effective urinary concentrations 2