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

Treatment of Urinary Tract Infections

For uncomplicated UTIs in adult women, use nitrofurantoin 100 mg twice daily for 5 days as first-line therapy, followed by trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days or fosfomycin 3 g single dose as alternatives based on local resistance patterns. 1

First-Line Antibiotic Selection for Adults

The choice of empiric therapy depends critically on local antibiogram data and patient-specific factors:

Primary Options for Uncomplicated Cystitis in Women

• Nitrofurantoin monohydrate/macrocrystals: 100 mg twice daily for 5-7 days, with clinical efficacy of approximately 93% 1, 2
• Trimethoprim-sulfamethoxazole (TMP-SMX): 160/800 mg twice daily for 3 days, with clinical efficacy of approximately 93%, but only if local resistance rates are <20% 1, 2
• Fosfomycin trometamol: 3 g single dose, with clinical efficacy of approximately 91% 1, 2

Important Caveat on Fluoroquinolones

• Avoid fluoroquinolones (ciprofloxacin, levofloxacin) for uncomplicated UTIs due to resistance concerns and adverse effects, reserving them only for complicated infections or pyelonephritis 1, 3
• Fluoroquinolones should be considered second-line agents despite their effectiveness 2

Second-Line Options

• β-lactam agents (amoxicillin-clavulanate 20-40 mg/kg per day in 3 doses, cephalexin 50-100 mg/kg per day in 4 doses) are less effective as empirical first-line therapy but may be used when first-line agents are contraindicated 4, 2

Treatment Duration

Treat acute cystitis episodes with as short a duration as reasonable, generally no longer than 7 days. 4

• 3-day courses are appropriate for TMP-SMX 1, 2
• 5-7 day courses for nitrofurantoin 1, 2
• Single-dose therapy for fosfomycin 1, 2
• Evidence shows 1-3 day courses for febrile UTIs are inferior and should be avoided 4

Special Populations

Febrile Infants and Children (2-24 months)

Most children can be treated orally, but those appearing "toxic" or unable to retain oral intake require parenteral antibiotics. 4

Oral Options for Pediatric Patients:

• Amoxicillin-clavulanate: 20-40 mg/kg per day in 3 doses 4
• Cephalosporins (cefixime 8 mg/kg per day in 1 dose, cefpodoxime 10 mg/kg per day in 2 doses) 4
• TMP-SMX: 6-12 mg/kg trimethoprim and 30-60 mg/kg sulfamethoxazole per day in 2 doses 4

Parenteral Options for Pediatric Patients:

• Ceftriaxone: 75 mg/kg every 24 hours 4
• Cefotaxime: 150 mg/kg per day divided every 6-8 hours 4
• Gentamicin: 7.5 mg/kg per day divided every 8 hours 4

Critical pediatric consideration: Nitrofurantoin should NOT be used in febrile infants because it does not achieve adequate parenchymal and serum concentrations to treat pyelonephritis or urosepsis 4

Total treatment duration for febrile pediatric UTIs should be 7-14 days, transitioning from parenteral to oral once clinical improvement occurs (typically 24-48 hours) 4

Men with Acute Cystitis

• Treat for 7-14 days based on limited observational data 2
• Use the same first-line agents as for women (nitrofurantoin, TMP-SMX, fosfomycin) 2

Women with Diabetes

• Treat similarly to women without diabetes if no voiding abnormalities are present 2
• Use standard first-line agents for the same duration 2

Postmenopausal Women with Recurrent UTIs

• Consider vaginal estrogen replacement as preventive therapy in addition to acute treatment 1
• Follow the same acute treatment regimens as younger women 1

Recurrent UTIs (≥3 UTIs in 1 year or ≥2 in 6 months)

Obtain urine culture with sensitivity testing prior to initiating treatment with each symptomatic episode. 4, 1

Management Algorithm:

• Document positive cultures with each symptomatic episode to confirm true recurrence 4
• Consider patient-initiated treatment (self-start) for select reliable patients while awaiting culture results 4
• Treat each acute episode with first-line agents for standard durations 4
• Implement preventive strategies: increased fluid intake, vaginal estrogen (postmenopausal women), cranberry products, probiotics 1

Antimicrobial Stewardship Principles

Always check local antibiogram data before selecting empiric therapy, as resistance patterns vary substantially by geographic region. 4, 3

• Avoid broad-spectrum antibiotics when narrow-spectrum agents are effective 4
• TMP-SMX and fluoroquinolones have high resistance rates in many communities, precluding their empiric use 3, 5
• Recent antibiotic exposure increases resistance risk; avoid recently used agents 3

Diagnostic Considerations

Obtain urinalysis and urine culture before initiating treatment in patients with recurrent UTIs. 4, 1

• For uncomplicated first-time cystitis in young healthy women, diagnosis can be made clinically without office visit or culture based on focused history of dysuria, frequency, urgency, and absence of vaginal discharge 1, 2
• If initial specimen is suspect for contamination, obtain catheterized specimen 4
• Do not treat asymptomatic bacteriuria in non-pregnant adults, as treatment may be harmful 4

Resistant Organisms

For culture-proven resistance to oral antibiotics:

• Treat with culture-directed parenteral antibiotics for as short a course as reasonable, generally no longer than 7 days 4
• For ESBL-producing organisms, oral options include nitrofurantoin, fosfomycin, and pivmecillinam 3
• Parenteral options for ESBL organisms include carbapenems, piperacillin-tazobactam (E. coli only), ceftazidime-avibactam 3

Common Pitfalls to Avoid

• Never use nitrofurantoin for febrile UTIs or pyelonephritis in any age group due to inadequate tissue penetration 4
• Avoid empiric fluoroquinolones for uncomplicated cystitis; reserve for complicated infections 1, 3
• Do not use β-lactams as first-line empiric therapy due to inferior efficacy compared to nitrofurantoin, TMP-SMX, or fosfomycin 2
• Do not delay treatment awaiting culture results in symptomatic patients; initiate empiric therapy immediately 2