The cause of urinary tract infection is usually bacteria originating in the gastrointestinal tract and reaching the urinary tract via the ascending urethra. In the neonatal period, on the other hand, the infection usually spreads via the bloodstream. The most common pathogen causing UTIs is E.coli.

The symptoms and clinical course of a urinary tract infection vary depending on the age of the patient.

In infants:

• fever,
• vomiting,
• lethargy/irritability,
• lack of appetite/weight gain,
• jaundice,
• septicaemia,
• foul-smelling urine,
• febrile convulsions.

In older children:

• painful urination,
• frequent urination,
• abdominal or lumbar pain,
• fever,
• drowsiness
• lack of appetite,
• vomiting,
• diarrhoea,
• haematuria,
• cloudy urine with unpleasant odour,
• secondary bed-wetting.

The primary diagnostic test is a thorough analysis of the urine passed. In children who urinate into nappies, the urine can be collected by direct 'catching' into a sterile container after the nappy has been removed (recommended method). In older children, urine is collected from the midstream. It is necessary to ensure sterile conditions - washing the child thoroughly to prevent contamination of the urine with bacteria of the genital area skin. Ideally, microscopic and bacteriological examination is performed immediately after collection. This is recommended for all children with suspected UTIs under 3 years of age. If this is not possible, the urine should be stored in the refrigerator. The diagnosis can be confirmed with almost certainty when an increase in homogeneous bacterial flora with a titre of > 105 colonies in 1 ml of a properly collected urine sample is observed. A urinalysis should be performed in any infant with fever>38°C of unclear cause.

If urinary tract infections are recurrent since birth, the cause should be sought in urinary tract defects.

For patients under 3 months of age with suspected urinary tract infection or in severe condition, immediate hospitalisation is indicated. Intravenous antibiotic therapy must be implemented until the fever subsides. Older children and patients with acute pyelonephritis can be treated with oral antibiotics. The choice of antibiotic must be adapted to the sensitivity of the cultured bacterial flora.

For the prevention of UTIs, it is important to take in large amounts of fluids, take care to empty the bladder regularly, remember proper and thorough perineal toileting, use so-called double micturition - emptying the bladder again 1-2 min after the end of urination to avoid urine retention, and use probiotics colonising the gut to reduce colonies of pathogenic flora that may be a potential source of infection.