What is the empiric treatment for pediatric Urinary Tract Infections (UTI)?

Empiric Treatment of Pediatric Urinary Tract Infections

For empiric treatment of pediatric UTIs, amoxicillin-clavulanate, trimethoprim-sulfamethoxazole, or a third-generation cephalosporin should be selected based on patient age, severity of infection, and local resistance patterns. The choice between oral and parenteral therapy depends on the child's clinical status rather than efficacy, as both routes are equally effective when appropriately selected.

Age-Based Treatment Algorithm

Newborns and Infants <6 months:

• First-line therapy: Parenteral treatment with:
  • Ampicillin plus aminoglycoside (gentamicin 7.5 mg/kg/day divided every 8 hours) OR
  • Third-generation cephalosporin (ceftazidime 100-150 mg/kg/day divided every 8 hours) 1

Children 6 months to 24 months:

• For uncomplicated pyelonephritis: Third-generation cephalosporin (oral cefixime 8 mg/kg/day once daily or parenteral ceftriaxone 75 mg/kg/day once daily) 1
• For complicated pyelonephritis: Ceftazidime plus ampicillin, or aminoglycoside plus ampicillin 1
• For lower UTI: Oral amoxicillin-clavulanate (20-40 mg/kg/day in 3 doses) or trimethoprim-sulfamethoxazole (6-12 mg/kg trimethoprim and 30-60 mg/kg sulfamethoxazole per day in 2 doses) 1, 2

Children >2 years:

• For uncomplicated UTI: Oral therapy with:
  • Amoxicillin-clavulanate (20-40 mg/kg/day in 3 doses) OR
  • Trimethoprim-sulfamethoxazole (6-12 mg/kg trimethoprim component per day in 2 doses) OR
  • Cephalexin (50-100 mg/kg/day in 4 doses) 1, 2, 3

Route of Administration Considerations

• Parenteral therapy is indicated when:

  • Child appears toxic
  • Unable to tolerate oral intake
  • Compliance with oral medication is uncertain
  • Suspected urosepsis 1

• Transition from parenteral to oral therapy can occur once clinical improvement is observed (usually within 24-48 hours) 1

Duration of Treatment

• Lower UTI: 7 days
• Pyelonephritis/Upper UTI: 7-14 days 1

Important Considerations for Antibiotic Selection

Local Resistance Patterns

• Trimethoprim-sulfamethoxazole resistance has increased significantly (up to 24% nationally), making it a poor empiric choice in many regions 4
• E. coli resistance to ampicillin is high across all pediatric age groups (40.6-52.8%) 5
• First-generation cephalosporins and nitrofurantoin have maintained low resistance rates for E. coli 4

Age-Specific Pathogen Distribution

• E. coli is the predominant pathogen in females (83%) but accounts for only 50% of infections in males 4
• Males have higher rates of Enterococcus (17%), Proteus mirabilis (11%), and Klebsiella (10%) 4

Medication-Specific Considerations

• Nitrofurantoin: Effective for lower UTIs but should not be used for febrile UTIs/pyelonephritis as it doesn't achieve adequate serum or renal parenchymal concentrations 1
• Fluoroquinolones: Generally avoided in pediatric patients due to potential adverse effects and increasing resistance 1, 2

Common Pitfalls to Avoid

1. Using nitrofurantoin for pyelonephritis: Despite low resistance rates, nitrofurantoin achieves inadequate serum and parenchymal concentrations for treating upper UTI/pyelonephritis 1

2. Relying on trimethoprim-sulfamethoxazole without local susceptibility data: Resistance rates have increased significantly, with studies showing up to 31% resistance in male patients 4

3. Treating asymptomatic bacteriuria: This may be harmful and contribute to antimicrobial resistance 1

4. Inadequate duration of therapy: Short courses (1-3 days) are inferior to 7-14 day regimens for febrile UTIs 1

5. Not adjusting empiric therapy based on culture results: Initial empiric therapy should be adjusted once urine culture and susceptibility results are available 2

By following these evidence-based recommendations and considering local resistance patterns, clinicians can optimize empiric treatment of pediatric UTIs while minimizing the risk of treatment failure and antimicrobial resistance.