See also

Febrile child
Sepsis
Suprapubic aspirate
Urinary samples

Key points

1. Signs and symptoms of urinary tract infection (UTI) are often non-specific in infants and young children
2. Urine dipstick is a useful screening test, but a positive urine culture with pyuria is required to confirm the diagnosis
3. Oral antibiotics are appropriate for most children with UTI. Children who are seriously unwell/septic, infants <6 months with structural abnormalities and infants <3 months usually require IV antibiotics
4. Ultrasound during the acute stage of illness is recommended for all children with atypical UTI, and in infants <6 months of age with recurrent UTI or who have not had antenatal monitoring to exclude renal tract abnormalities
5. Collecting urine to exclude UTI is not required if there is another clear focus of fever and the child is not systemically unwell

Background

A UTI is a bacterial infection of the bladder and urinary tract

• Recurrent UTI is either:
  • ≥2 episodes of acute upper UTI (pyelonephritis)
  • 1 episode of UTI with acute upper UTI and ≥1 episode of lower UTI (cystitis)
  • ≥3 episodes of UTI with lower UTI
• Atypical UTI:
  • seriously ill
  • septicaemia
  • lack of response to appropriate antibiotics within 48 hours
  • infection with organisms other than E coli
  • raised creatinine
  • poor urine flow
  • abdominal or bladder mass
• Signs and symptoms of UTI can be non-specific, and overlap with common viral illnesses, especially in younger children
• A urine sample is required to diagnose or exclude UTI when clinically suspected
• Consider UTI in any child if fever without focus persists after 48 hours

Assessment

History

• Infants and pre-verbal children often present with non-specific symptoms such as fever, vomiting, poor feeding, jaundice, lethargy, faltering growth (infants), and irritability
• Older children may present with more typical signs and symptoms such as dysuria, hesitancy, urinary frequency or new daytime accidents, haematuria, lower abdominal and loin pain
• Enquire about previous UTI, and previous imaging if applicable
• Risk factors include:
  • younger age
  • high-grade vesicoureteral reflux
  • congenital abnormalities of the urinary tract, or abnormal urinary stream.
  • instrumentation of the urinary tract (particularly indwelling bladder catheterisation)
  • renal stones
  • bowel and/or bladder dysfunction, including secondary to constipation and spina bifida

Examination

• Examination may be normal other than the presence of fever
• Lower abdominal or loin tenderness may be present
• Non-specific findings include dehydration and lethargy
• Check blood pressure

Assessment of severity

• Clinical distinction between cystitis and pyelonephritis can be difficult, especially in younger children
• Cystitis is suggested by features such as dysuria, frequency, urgency and lower abdominal discomfort
• Pyelonephritis is suggested by systemic features such as fever, rigors, malaise, vomiting and loin tenderness

Management

Investigation

Children with suspected UTI should have a urine sample collected; dipstick and microscopy screening can guide initial management. Check culture results after 24-48 hours to confirm or adjust management as appropriate

Urine samples should be collected prior to starting antibiotics (unless the child is seriously unwell and requires immediate IV therapy)

Urine collection:

• The perineal/genital area should be cleaned with saline-soaked gauze for 10 seconds before collecting clean catch urine. Do not use antiseptic solution. Be ready to collect urine sample opportunistically while cleaning
• Suprapubic aspirate (see SPA): gold standard in children up to 6 months (low risk of contamination)
• In/out catheter: useful if the bladder is underfilled, such as after a failed clean catch or SPA (discard first few drops of urine if possible, to reduce contamination) (low-medium risk of contamination)
• Midstream urine (MSU): preferred method for toilet-trained children who can void on request (medium risk of contamination)
• Clean catch: appropriate for pre-continent children who cannot void on request, but are not seriously unwell (medium risk of contamination)
  • Quick wee method: a method of obtaining a clean catch urine sample in infants. Stimulate the suprapubic area with sterile gauze soaked in cold saline for 5 minutes while simultaneously preparing to catch urine in a sterile specimen jar
• Bag urine: not recommended for culture due to high false positive rates (high risk of contamination)
• Specify method of collection on pathology request

Urine dipstick

• Urine dipstick is a useful screening test to guide initial management
• The presence of leukocytes and nitrites is suggestive of a UTI
• Dipstick results are less reliable in neonates and young infants, particularly due to false negatives

Guide to urine dipstick interpretation

Send urine samples for culture if:

• under 3 months old
• positive dipstick result for leukocyte esterase or nitrite
• child thought to have acute upper UTI
• recurrent UTI
• not responding to treatment within 24 to 48 hours
• clinical symptoms and signs of UTI without suggestive dipstick findings

Urine microscopy and culture

• Laboratory microscopy can complement dipstick results to guide initial management
• Bacteria and leukocytes on microscopy are suggestive of UTI. See Additional notes
• Epithelial cells (squames) suggest skin contamination and a poorly collected sample. Consider recollection if indicated
• A positive culture with sufficient growth and pyuria confirms UTI
• Growth of a single organism at >10⁸ CFU/litre (>10⁵ CFU/mL) from any collection method suggests infection
• Growth of a single organism at lower counts of 10^6-8 CFU/litre (>10^3-5 CFU/mL) from catheter suggests infection, and from clean catch or MSU may indicate early infection
• Growth of any amount from SPA suggests infection

Other investigations

• Febrile and unwell infants <4 weeks of age: FBE, blood culture, LP (and admit for IV antibiotics)
• Blood culture at any age, if sepsis suspected
• Consider LP if meningitis suspected at any age
• All children with atypical UTI (see criteria above) and infants <6 months of age with recurrent UTI or who have not had antenatal monitoring to exclude renal tract abnormalities
• Consider STI screen in sexually active young people

Treatment

• Any child who is seriously unwell and infants <3 months should be admitted for initial IV antibiotics. Oral antibiotics are usually appropriate for other children with uncomplicated UTI
• 3-5 day course for children with cystitis
• 7–10 day course for children with pyelonephritis

Antimicrobial recommendations may vary according to local antimicrobial susceptibility patterns; please refer to local guidelines

Oral treatment

• Cystitis: Cefalexin 20 mg/kg (max 750 mg) oral tds
• Pyelonephritis:
  • <12 months Cefalexin 25 mg/kg (max 1.5 g) oral qid
  • ≥12 months Cefalexin 45 mg/kg (max 1.5 g) oral tds

IV treatment

• Do not delay antibiotic therapy for a child who is seriously unwell, even if a urine sample has not been obtained
• Recommended empiric IV antibiotics: gentamicin + benzylpenicillin (check gentamicin levels and renal function as per local guidelines if continuing gentamicin beyond 48 hours)
• Switch to oral antibiotics when clinically improved and/or tolerating oral

Follow up

• Most children do not require an ultrasound for a first UTI. A non-urgent renal ultrasound should be arranged for children who have recurrent UTIs
• Routine antibiotic prophylaxis is not generally recommended. Specialist follow-up should be arranged for children with recurrent UTI or known renal anomalies

Consider consultation with local paediatric team when

• under 6 months of age
• known renal tract anomalies
• not responding to initial therapy
• seriously unwell

Consider transfer when

Any child requiring care beyond the level of comfort of the treating hospital

For emergency advice and paediatric or neonatal ICU transfers, see Retrieval Services.

Consider discharge when

Tolerating oral fluids and antibiotics

Parent information

Children's Health Queensland: Urinary tract infection

Kids Health Information: Urinary tract infection

The Sydney Children's Hospitals Network: Urinary tract infection

Children's Health Queensland: How to collect a clean urine specimen

Kids Health Information: Urine Tests

Additional notes

Interpreting urine test results

• Blood and protein are not reliable markers of UTI
• Nitrites are not produced by all urinary organisms. Absence of nitrites on dipstick does not exclude UTI
• Leukocytosis can occur with other febrile illnesses (e.g. viral infections, appendicitis). Leukocytosis alone on microscopy does not confirm UTI
• Leukocytosis may be absent in early infection or very young children
• Leukocytes and bacteria seen on microscopy are suggestive of UTI, but a positive culture is required to confirm the diagnosis
• Pure growth at low colony counts (CFU) may indicate early infection. Consider sample recollection or empiric treatment if the child remains unwell

Last updated October 2025