Antibiotic Management for Pediatric Urinary Tract Infections
First-Line Oral Antibiotics for Uncomplicated UTI
For children with uncomplicated UTI, use amoxicillin-clavulanic acid, trimethoprim-sulfamethoxazole, cephalexin, or nitrofurantoin as first-line oral therapy, with selection based on local resistance patterns. 1, 2
Age-Specific Treatment Recommendations
Neonates (<28 days)
- Hospitalize all neonates with febrile UTI 3
- Start parenteral ampicillin PLUS either cefotaxime or an aminoglycoside (gentamicin) 1, 3
- After 3-4 days of IV therapy with clinical improvement, transition to oral antibiotics to complete 14 days total 3
- Concomitant bacteremia occurs in 4-36% of neonatal UTIs, justifying aggressive parenteral therapy 1
Infants (28 days to 3 months)
- Clinically ill/toxic-appearing: Hospitalize and give parenteral third-generation cephalosporin (ceftriaxone or cefotaxime) OR gentamicin 1, 3
- Non-toxic appearing: May treat as outpatient with daily parenteral ceftriaxone or gentamicin until afebrile for 24 hours, then oral antibiotics 3
- Complete 14 days total therapy 3
Children >6 months with Pyelonephritis
- Uncomplicated pyelonephritis: Use oral third-generation cephalosporin OR parenteral ceftriaxone/gentamicin daily until afebrile 24 hours, then oral antibiotics 1, 3
- Complicated pyelonephritis: Hospitalize, give parenteral ceftriaxone or gentamicin until clinically improved and afebrile 24 hours 3
- Complete 10-14 days total therapy 2, 3
Children with Lower UTI (Cystitis)
- Moderately to severely symptomatic: Start oral antibiotics immediately with amoxicillin-clavulanic acid, trimethoprim-sulfamethoxazole, cephalexin, or nitrofurantoin 1, 2
- Mildly symptomatic: May wait for culture results before treating 3
- Complete 5-7 days of therapy for uncomplicated cystitis 3, 4
Critical Antibiotic Selection Considerations
Avoid These Common Errors
Do NOT use amoxicillin alone - E. coli resistance to amoxicillin is 75% globally (range 45-100%), making it inappropriate for empiric therapy 1, 2
Do NOT use nitrofurantoin for febrile UTI or pyelonephritis - inadequate tissue penetration makes it unsuitable for upper tract infections 2
Do NOT use fluoroquinolones in children - serious safety concerns affecting tendons, muscles, joints, and nervous system 1, 2
Do NOT use third-generation cephalosporins (cefixime) for uncomplicated cystitis - reserve broader-spectrum agents for pyelonephritis to reduce resistance 5
Preferred First-Line Agents
- Cephalexin: Narrow-spectrum, highly effective for uncomplicated UTI with excellent safety profile 5
- Amoxicillin-clavulanic acid: Maintains high susceptibility against urinary E. coli isolates 1, 2
- Trimethoprim-sulfamethoxazole: Equivalent efficacy to broader agents when local resistance <20% 1
- Nitrofurantoin: Excellent for lower UTI only, minimal resistance development 1
Route of Administration Decision Algorithm
Oral therapy is appropriate when:
- Child can retain oral intake 2
- Not clinically toxic-appearing 2
- Reliable follow-up and medication compliance 2
Parenteral therapy is required when:
- Age <28 days (all cases) 3
- Clinically toxic or septic appearance 2, 3
- Unable to retain oral medications (vomiting) 2
- Uncertain compliance with oral regimen 2
- Complicated pyelonephritis 3
Treatment Duration
- Neonates and young infants (<3 months): 14 days total 3
- Pyelonephritis (uncomplicated): 10-14 days 2, 3
- Lower UTI/cystitis: 5-7 days 3, 4
Essential Clinical Pitfalls to Avoid
Do NOT treat asymptomatic bacteriuria - treatment may be harmful and promotes resistance 2
Do NOT diagnose UTI with polymicrobial growth - this indicates contamination, not true infection; 58% of inappropriately diagnosed UTIs had polymicrobial cultures 6
Do NOT prescribe antibiotics before confirming UTI - requires pyuria (>5 WBC/hpf or positive leukocyte esterase) PLUS positive culture (≥50,000 CFU/mL catheterized or ≥100,000 CFU/mL clean catch) PLUS symptoms 6
Initiate treatment within 48 hours of fever onset - delays beyond 48 hours increase risk of renal scarring 7
Verify local antibiogram data - resistance patterns vary significantly by region; empiric choices should reflect local susceptibility rates <10% for pyelonephritis and <20% for cystitis 1