Switch to amoxicillin-clavulanate oral therapy in urinary tract infection caused by extended-spectrum beta-lactamase-producing Escherichia coli: Assessment by chronic phase technetium-99m dimercaptosuccinic acid renal Scintigraphy images.

The incidence of urinary tract infection (UTI) caused by extensive beta-lactamase-producing Escherichia coli (ESBL-EC) is increasing, including in children. However, the available oral antibiotic treatment options for ESBL-EC are limited. Herein, we report the cases of two children diagnosed with UTI caused by ESBL-EC (ESBL-UTI) who were switched from empirical intravenous antibiotics in UTI to amoxicillin-clavulanic acid (AMPC/CVA) (14:1) after the causative organism was found to be ESBL-EC. A 3-month-old infant and an 8-month-old infant were admitted to our hospital with the chief complaint of fever. In both cases, UTI was suspected based on urinalysis results, and intravenous cefotaxime was started as an empiric antibiotic. In both cases, ESBL-EC was detected in urine culture, and the diagnosis of ESBL-UTI was confirmed. Results of antimicrobial susceptibility testing showed resistance to cefotaxime, but fever resolution was obtained in both cases following administration of intravenous cefotaxime. Since fever resolution was achieved, the antimicrobial was switched to oral AMPC/CVA (14:1) monotherapy with reference to antimicrobial susceptibility testing, and the two patients were discharged on days 5-6 of hospitalization. Antimicrobials were administered intravenously and orally for a total of 2 weeks. Chronic-phase technetium-99m dimercaptosuccinic acid renal scintigraphy showed no renal scarring. ESBL-UTI may require 2 weeks of intravenous antibacterial therapy, but in this case, both patients could be treated without renal scarring after conversion to oral AMPC/CVA alone. Since this is important to shorten the length of hospital stay, we will study the effect of this treatment modality in more cases in the future.