Approach to managing UTI in neonates and children younger than 3 months

In neonates (children younger than 1 month), treat suspected UTI as for sepsis or septic shock of unknown source, until differential diagnoses (including meningitis) are excluded. To find the right empirical antibiotic regimen, see Choice of empirical antibiotic regimen for sepsis or septic shock in neonates and children younger than 2 months.

In children 1 month to younger than 3 months who have fever (38°C or higher) or are unwell (eg irritable, not tolerating oral feeds), treat suspected UTI as for sepsis or septic shock of unknown source, until differential diagnoses (including meningitis) are excluded. To find the right empirical antibiotic regimen for:

Children 1 month to younger than 3 months with suspected UTI who are afebrile and well (eg tolerating oral feeds, not irritable) can be treated with oral antibiotics and close follow-up. Because it can be difficult to distinguish pyelonephritis and cystitis in young children, treat with an oral antibiotic regimen for acute pyelonephritis.

If available, modify treatment based on the results of investigations, including susceptibility testing.

For neonates, intravenous antibiotic therapy is usually recommended for the full duration of treatment. However, evidence suggests that adequate blood concentrations of antibiotics can be achieved for neonates treated with oral antibioticsHikmat, 2022Keij, 2019. Oral antibiotics can be used to complete therapy for UTI in neonates who significantly improve on initial intravenous therapy and in whom intravenous access is challenging.

For children 1 month to younger than 3 months who are initially treated with intravenous therapy, consider switching to oral therapy to complete the course when the child is clinically improved and can tolerate and absorb oral therapy (eg tolerating oral feeds).