Urine specimens should be obtained for urinalysis and urine culture prior to antibiotic therapy. In febrile children with signs of UTI, antibiotic therapy should be started as early as possible to eradicate the infection, prevent bacteremia, improve clinical outcome, and reduce the likelihood of acute phase renal damage and the risk of renal scarring. If a child has a febrile UTI without a previous normal US, a urinary US should be performed within 24 hours to rule out obstructive nephropathy, depending on the clinical situation. Asymptomatic bacteriuria If ABU is not associated with leukocyturia, antibiotic therapy should be avoided unless the UTI is causing complications or the patient intends to have surgical treatment. A Swedish screening study found that 0.9% of boys <1 year of age and 2.5% of girls had ABU by SPA testing. near the time of testing, one boy and one girl each of these infants developed pyelonephritis symptoms; the others remained asymptomatic. The mean duration of bacteriuria for girls and boys was 2 and 1.5 months, respectively. Therefore, screening for ABU for therapeutic purposes is not recommended, regardless of the method used to collect urine. Cystitis in children 3 months of age Although there appears to be an advantage to >1-2 days of treatment for these children, the data on antibiotic regimens in this setting are controversial. Therefore, a minimum of 3-4 days of oral therapy is required for patients with uncomplicated cystitis. Febrile children: route of administration These factors need to be considered when choosing oral or parenteral therapy: patient age; clinically suspected urinary sepsis; severity of illness; refusal of fluid, food, and/or oral administration; vomiting; diarrhea; noncompliance; and complicated febrile UTI (e.g., upper urinary tract dilatation). Parenteral antibiotic therapy is recommended for neonates and infants <2 months of age with an increased incidence of urinary sepsis and severe pyelonephritis. Severe electrolyte imbalance may occur in such cases. And this life-threatening hyponatremia and hyperkalemia is derived from pseudoaldosteronism. Combined treatment with ampicillin and an aminoglycoside (e.g., tobramycin or gentamicin) or a third-generation cephalosporin can be very efficacious. A single daily dose of an aminoglycoside is as safe and effective as twice a day. The incidence of antibiotic resistance in uropathogenic E. coli varies markedly among countries, with high rates of resistance in Iran and Vietnam. An upcoming study reports UTI in children caused by ultra broad-spectrum beta-lactamase (ESBL)-producing E. coli. a Turkish study showed that 49% of children <1 year of age and 38% of children >1 year of age carried ESBL-producing bacteria. Of these, 83% were resistant to methicillin/sulfamethoxazole, 18% were resistant to furantoin, 47% were resistant to quinolones, and 40% were resistant to aminoglycosides. Fortunately, for children it appears that these results are similar to those of non-ESBL-producing bacteria. However, one study concluded that initial empirical intravenous antibiotic therapy was inappropriate. Drug selection is also based on the type of local antimicrobial susceptibility and is later adjusted based on isolated uropathogen susceptibility testing. Not all available antibiotics are approved by national health authorities for the treatment of the pediatric population, especially infants. Regimen of febrile urinary tract infections The regimen of parenteral agents remains controversial. The consensus of the guideline expert panel and the recommendation of the AAP is this: parenteral antibiotic therapy should be used until the child is free of fever, after which oral antibiotic therapy should be continued for 7 to 14 days. If outpatient treatment is chosen after the infant, adequate monitoring and medical supervision needs to be ensured and treatment adjusted if necessary. During the initial phase of treatment, the physician should maintain close contact with the child’s family. For complicated UTI caused by uropathogens other than E. coli, treatment with parenteral broad-spectrum antibiotics is recommended. For obstructive nephropathy, temporary urinary diversion is required depending on clinical status and/or response to antibiotic therapy.