Treatment of Urinary Tract Infections (UTIs)
For uncomplicated UTIs in otherwise healthy adult non-pregnant females, first-line empiric therapy should be a 5-day course of nitrofurantoin, a 3-g single dose of fosfomycin, or a 5-day course of pivmecillinam. 1
Classification of UTIs
UTIs are categorized according to:
- Location: Upper (pyelonephritis) vs. lower (cystitis) urinary tract
- Severity: Uncomplicated vs. complicated
- Uncomplicated UTIs: Occur in healthy non-pregnant women with no structural/functional abnormalities
- Complicated UTIs: Occur in men, pregnant women, patients with structural/functional abnormalities, immunocompromised patients, or those with bacteremia 1
First-Line Treatment Options for Uncomplicated UTIs
| Antibiotic | Dose | Duration |
|---|---|---|
| Nitrofurantoin | 100 mg twice daily | 5 days |
| Fosfomycin | 3g single dose | - |
| Pivmecillinam | 400 mg twice daily | 5 days |
Second-Line Treatment Options for Uncomplicated UTIs
| Antibiotic | Dose | Duration |
|---|---|---|
| Trimethoprim-sulfamethoxazole | 160/800 mg twice daily | 3 days |
| Amoxicillin-clavulanate | 500/125 mg twice daily | 3-7 days |
| Cephalexin | 500 mg four times daily | 5-7 days |
Treatment for Complicated UTIs
The European Association of Urology recommends the following for complicated UTIs with systemic symptoms 2:
Strong recommendation: Use a combination of:
- Amoxicillin plus an aminoglycoside
- A second-generation cephalosporin plus an aminoglycoside
- An intravenous third-generation cephalosporin
Treatment duration: 7-14 days (depending on resolution of symptoms and underlying factors) 2
Special Considerations
Fluoroquinolones
- Only use ciprofloxacin if local resistance rate is <10% 2
- Do not use fluoroquinolones for empirical treatment in patients from urology departments or when patients have used fluoroquinolones in the last 6 months 2
- Levofloxacin is FDA-approved for uncomplicated UTIs due to E. coli, K. pneumoniae, or S. saprophyticus 3
Pregnant Women
- Avoid trimethoprim-sulfamethoxazole in first and third trimesters 1
- Nitrofurantoin or cephalexin are recommended as first-line treatments 1
Recurrent UTIs
- Before antimicrobial prophylaxis, confirm eradication of previous UTI with negative urine culture 1-2 weeks after treatment 2
- Consider continuous antimicrobial prophylaxis when non-antimicrobial measures have been unsuccessful 2
- Post-coital antimicrobial prophylaxis may be effective for women with post-coital infections 2, 1
Treatment of Resistant Pathogens
Extended-Spectrum β-Lactamases (ESBL)-producing Enterobacteriales
- Oral options: nitrofurantoin, fosfomycin, pivmecillinam 4
- Parenteral options: carbapenems, ceftazidime-avibactam, ceftolozane-tazobactam, aminoglycosides 4
Carbapenem-Resistant Enterobacteriales (CRE)
- Options include: ceftazidime-avibactam, meropenem/vaborbactam, imipenem/cilastatin-relebactam, colistin, fosfomycin, aminoglycosides 4
Multidrug-Resistant Pseudomonas
- For DTR-PA (difficult-to-treat P. aeruginosa): colistin monotherapy or combination therapy, ceftolozane/tazobactam, ceftazidime/avibactam, or imipenem/cilastatin/relebactam 2
Common Pitfalls to Avoid
Overuse of fluoroquinolones: Increasing resistance rates limit their empirical use 4, 5
Inadequate treatment duration:
- Too short for complicated UTIs may lead to treatment failure
- Too long for uncomplicated UTIs increases risk of adverse effects and antimicrobial resistance 1
Treating asymptomatic bacteriuria: This promotes resistance without clinical benefit 1
Failing to obtain urine cultures: Especially important before initiating antibiotics in complicated UTIs or recurrent infections 1
Performing surveillance urine cultures in asymptomatic patients: Not recommended 1
Non-Antibiotic Approaches for Prevention
- Increased fluid intake 1
- Cranberry products (modest effect) 2, 1
- D-mannose 1
- Vaginal estrogen with or without lactobacillus probiotics for postmenopausal women 1
- Methenamine hippurate 1
UTIs remain one of the most common bacterial infections requiring antibiotic treatment. With rising antimicrobial resistance, judicious antibiotic use following current guidelines is essential to preserve antibiotic effectiveness while ensuring optimal patient outcomes.