Management of Urinary Tract Infections
The management of urinary tract infections requires a targeted antimicrobial approach based on infection classification, with first-line therapy for uncomplicated cystitis being nitrofurantoin (100mg twice daily for 5 days), fosfomycin (3g single dose), or trimethoprim-sulfamethoxazole (if local resistance <20%). 1
Classification of UTIs
UTIs are classified into:
Uncomplicated UTIs:
- Acute cystitis in non-pregnant women without anatomical or functional abnormalities
- Uncomplicated pyelonephritis
Complicated UTIs:
- Presence of anatomical/functional abnormalities
- Male gender
- Pregnancy
- Diabetes mellitus
- Immunosuppression
- Healthcare-associated infections
- Presence of multidrug-resistant organisms
- Catheter-associated UTIs
Treatment Algorithm
1. Uncomplicated Cystitis in Women
First-line options 1:
- Nitrofurantoin 100mg twice daily for 5 days
- Fosfomycin trometamol 3g single dose
- Trimethoprim-sulfamethoxazole 160/800mg twice daily for 3 days (only if local resistance <20%)
Second-line options:
- Cephalexin or cefixime
- Amoxicillin-clavulanate
- Fluoroquinolones (restricted use due to collateral damage concerns)
2. Uncomplicated Pyelonephritis
Oral treatment (mild to moderate cases) 1:
- Ciprofloxacin 500-750mg twice daily for 7 days
- Levofloxacin 750mg daily for 5 days
- Trimethoprim-sulfamethoxazole 160/800mg twice daily for 14 days
- Cefpodoxime 200mg twice daily for 10 days
- Ceftibuten 400mg daily for 10 days
Note: If fluoroquinolones are used empirically, an initial IV dose of a long-acting parenteral antimicrobial (e.g., ceftriaxone) should be administered.
Intravenous treatment (severe cases) 1:
- Ceftriaxone 1-2g daily
- Ciprofloxacin 400mg twice daily
- Levofloxacin 500mg daily
- Cefepime 1-2g twice daily
- Piperacillin-tazobactam 4.5g every 8 hours
3. Complicated UTIs
Treatment duration: 7-14 days (14 days for men when prostatitis cannot be excluded) 1
Empirical IV therapy options 1:
- Amoxicillin plus an aminoglycoside
- Second-generation cephalosporin plus an aminoglycoside
- Third-generation cephalosporin
Oral therapy options (after culture results):
- Based on susceptibility testing
- Duration should be related to treatment of underlying abnormality
4. Catheter-Associated UTIs
- Remove or change catheter if possible
- Treat only symptomatic infections
- Obtain cultures before initiating antibiotics
- Choose antibiotics based on local resistance patterns and prior culture data
Special Considerations
Antimicrobial Resistance
- ESBL-producing organisms: Consider nitrofurantoin, fosfomycin, carbapenems, or newer agents like ceftazidime-avibactam 2
- Carbapenem-resistant Enterobacteriaceae: Consider ceftazidime-avibactam, colistin, fosfomycin, or aminoglycosides 2
- MDR Pseudomonas: Consider ceftolozane-tazobactam, ceftazidime-avibactam, or carbapenems 2
Asymptomatic Bacteriuria
Do not screen or treat asymptomatic bacteriuria except in 1:
- Pregnant women
- Before urological procedures breaching the mucosa
Common Pitfalls to Avoid
Overtreatment of asymptomatic bacteriuria: Treating asymptomatic bacteriuria can lead to unnecessary antibiotic exposure and increased resistance.
Fluoroquinolone overuse: Restrict use due to increasing resistance rates and collateral damage (selection of multi-resistant pathogens) 1, 2.
Inadequate treatment duration: Ensure appropriate duration based on infection type and severity.
Failure to obtain cultures in complicated UTIs: Always obtain cultures before starting antibiotics in complicated UTIs to guide targeted therapy.
Neglecting to address underlying anatomical or functional abnormalities: Management of the underlying condition is essential for successful treatment of complicated UTIs 1.
By following this evidence-based approach to UTI management, clinicians can optimize outcomes while minimizing antimicrobial resistance and adverse effects.