- Primary pathogens (Escherichia coli · Klebsiella species · Proteus mirabilis · Enterococcus species (less common))
- Age and terminology (Febrile UTI is mainly used in infants and young children · AAP guideline population: 2–24 months · in older children with fever and upper tract signs, use acute pyelonephritis)
First-line therapy
Ceftriaxone • i.v. • 50–75 mg/kg/day • 1×/day
Max 2000 mg/day · Duration: 7–10 days · Total IV plus oral course; AAP cites 7–14 days for initial febrile UTI — extend if slow response
Enter weight on Kids to calculate doses
Gentamicin • i.v./i.m. • 5–7.5 mg/kg/day • 1×/day
Duration: 7–10 days · Extended-interval once daily (CPS 5–7.5 mg/kg/day); monitor levels if >48 h; often with ampicillin
- • Gentamicin: CPS 5–7.5 mg/kg/day i.v./i.m. once daily (extended interval); often combined with ampicillin — alternative divided regimen 2–2.5 mg/kg/dose i.v. 3×/day (7.5 mg/kg/day total).
- • Cefixime: oral step-down when culture confirms susceptibility; AAP/CPS support oral initial therapy in nontoxic children able to tolerate p.o.
- • Amoxicillin/clavulanate: step-down when E. coli is susceptible; covers beta-lactamase producers per local antibiogram.
- • AAP: oral and parenteral routes are equally effective for initial therapy — choose based on clinical severity and practical considerations.
- • Neonates and infants <2 months: use different empiric regimens per local protocol (e.g. cefotaxime ± gentamicin) — not this first-line cephalosporin tier.
Enter weight on Kids to calculate doses
Clinical notes
- • AAP guideline applies to febrile infants and children 2–24 months; neonates and infants <2 months require separate empiric protocols.
- • Diagnosis (AAP): pyuria plus ≥50 000 CFU/mL of a single uropathogen from catheter or suprapubic aspirate — bag urine is for screening only.
- • Urine culture: obtain by catheter or SPA before antibiotics when UTI is suspected; mandatory if antimicrobial therapy will start without delay.
- • Blood culture: obtain when ill-appearing, age <2–3 months, or when bacteremia cannot be excluded — before antibiotics in febrile infants without a clear source.
- • Hospital admission: toxic appearance, dehydration, vomiting, age <2–3 months (per local protocol), failed outpatient therapy, or inability to ensure follow-up and oral intake.
- • AAP — Urinary Tract Infection Clinical Practice Guideline (2–24 months) (2011)
- • AAP Reaffirmation — Febrile UTI in infants and young children (2016)
- • AAP Red Book — Urinary Tract Infections (2024)
+ 4 more
- • Canadian Paediatric Society — Urinary tract infections in children (2024)
- • ESPU / EAU Guidelines on Paediatric Urology (UTI sections) (2024)
- • NICE NG111 — Urinary tract infection (principles applicable) (2018)
- • WHO Pocket Book of Hospital Care for Children (2022)