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

Treatment of Urinary Tract Infections

For uncomplicated cystitis in women, first-line treatment is fosfomycin 3g single dose, nitrofurantoin 100mg twice daily for 5 days, or pivmecillinam 400mg three times daily for 3-5 days, with fluoroquinolones reserved only for complicated infections. 1

Uncomplicated Cystitis in Women

First-Line Antibiotics

• Fosfomycin trometamol: 3g single dose for 1 day 1
• Nitrofurantoin: 100mg twice daily for 5 days (multiple formulations available including macrocrystals or monohydrate) 1, 2
• Pivmecillinam: 400mg three times daily for 3-5 days 1

These agents are preferred because they maintain high efficacy against E. coli (the causative organism in >90% of uncomplicated UTIs) while minimizing resistance development 3, 4.

Second-Line Options (When First-Line Contraindicated)

• Trimethoprim: 200mg twice daily for 5 days (avoid in first trimester pregnancy) 1
• Trimethoprim-sulfamethoxazole (TMP-SMX): 160/800mg twice daily for 3 days (avoid in last trimester pregnancy) 1, 5, 2
• Cephalosporins (e.g., cefadroxil): 500mg twice daily for 3 days, only when local resistance patterns favor them 1

Critical Pitfall: Fluoroquinolones should NOT be used as first-line therapy for uncomplicated cystitis and must be reserved for complicated infections or when resistance patterns necessitate their use 1.

When to Obtain Urine Culture

Urine culture is NOT needed for typical uncomplicated cystitis but should be obtained in: 1

• Suspected acute pyelonephritis
• Symptoms not resolving or recurring within 4 weeks after treatment
• Atypical symptoms
• Pregnancy
• Recurrent UTIs

Alternative Approach for Mild Symptoms

For women with mild to moderate symptoms, symptomatic therapy with ibuprofen can be considered as an alternative to immediate antibiotics, reducing antibiotic exposure and resistance development 1.

Uncomplicated UTI in Men

Men require longer treatment duration (7 days minimum) due to potential prostatic involvement. 1

Recommended Regimens

• TMP-SMX: 160/800mg twice daily for 7 days 1
• Fluoroquinolones: According to local susceptibility testing for 7 days 1
• Nitrofurantoin: For 7 days 2

Important Consideration: Always consider urethritis and prostatitis in men presenting with UTI symptoms, as these require different management approaches 2. If prostatitis cannot be excluded, extend treatment to 14 days 6.

Acute Uncomplicated Pyelonephritis

Outpatient Oral Therapy

For patients who can be managed as outpatients: 6

• Ciprofloxacin: 500-750mg twice daily for 7 days (if local fluoroquinolone resistance <10%) 6
• Levofloxacin: 750mg once daily for 5 days 6
• TMP-SMX: 160/800mg twice daily for 14 days 6
• Cefpodoxime: 200mg twice daily for 10 days 6
• Ceftibuten: 400mg once daily for 10 days 6

Key Point: If using oral cephalosporins empirically, administer an initial intravenous dose of a long-acting parenteral antimicrobial (e.g., ceftriaxone) first 6.

Inpatient Parenteral Therapy

For patients requiring hospitalization: 6

• Ciprofloxacin: 400mg IV twice daily 6
• Levofloxacin: 750mg IV once daily 6
• Ceftriaxone: 1-2g IV once daily 6
• Cefepime: 1-2g IV twice daily 6
• Piperacillin/tazobactam: 2.5-4.5g IV three times daily 6
• Gentamicin: 5mg/kg IV once daily (with or without ampicillin) 6

Carbapenems and novel broad-spectrum agents should ONLY be used when early culture results indicate multidrug-resistant organisms. 6

Complicated UTIs

Complicated UTIs require 7-14 days of treatment, with the longer duration (14 days) recommended for men when prostatitis cannot be excluded. 6

Factors Defining Complicated UTI

Any of the following make a UTI "complicated": 6

• Obstruction at any site in urinary tract
• Foreign body (catheter, stent)
• Incomplete voiding
• Vesicoureteral reflux
• Recent instrumentation
• Male sex
• Pregnancy
• Diabetes mellitus
• Immunosuppression
• Healthcare-associated infection
• ESBL-producing or multidrug-resistant organisms

Empirical Treatment Approach

• Combination therapy: Amoxicillin plus aminoglycoside, OR second-generation cephalosporin plus aminoglycoside, OR intravenous third-generation cephalosporin 6
• Mandatory: Obtain urine culture and susceptibility testing before starting treatment 6
• Mandatory: Address underlying urological abnormality or complicating factor 6

The microbial spectrum is broader than uncomplicated UTIs, commonly including E. coli, Proteus spp., Klebsiella spp., Pseudomonas spp., Serratia spp., and Enterococcus spp., with higher antimicrobial resistance rates 6.

Treatment Failure Management

If symptoms do not resolve by end of treatment or recur within 2 weeks: 1

1. Obtain urine culture and antimicrobial susceptibility testing
2. Retreat with a 7-day regimen using a different antibiotic class
3. Consider evaluation for underlying urological abnormality, especially with rapid recurrence of the same organism

Do NOT obtain routine post-treatment cultures in asymptomatic patients, as this leads to overtreatment of asymptomatic bacteriuria. 1

Special Populations

Peri- and Post-Menopausal Women with Recurrent UTIs

Vaginal estrogen therapy should be recommended to reduce future UTI risk if no contraindication exists. 6 This is distinct from systemic estrogen therapy, which has not been shown to reduce UTI risk 6.

Recurrent UTI Prevention (Non-Antibiotic)

• Cranberry products: May be offered in formulations that are available and tolerable (juice or tablets), though evidence is limited by product variability 6
• Increased fluid intake: Can help prevent recurrence 2
• Methenamine hippurate: Can prevent recurrent infections 2

Catheter-Associated UTIs

These represent a distinct entity with 3-8% daily incidence of bacteriuria with indwelling catheters 6. Treatment duration and approach follow complicated UTI guidelines, with catheter removal or replacement being critical 6.