The Influence of Non-E. Coli or Extended-Spectrum β-Lactamase-Producing Bacterial Growth on the Follow-Up Procedure of Infants with the First Febrile Urinary Tract Infection

Objective To evaluate the effects of non- E. coli or extended-spectrum β-lactamase–positive (ESBL-positive) microorganism growth in the first febrile urinary tract infection (UTI) of infants on laboratory findings or renal parenchymal damage presenting the severity of inflammation, anatomic abnormalities defined by imaging studies, and recurrent UTIs in the follow-up period. Methods The data of patients aged between 2 and 24 mo and followed up for at least 6 mo with febrile UTI guideline of the authors’ pediatric-nephrology clinic, were retrospectively analyzed. Ultrasonography was performed in all the cases at the time of UTI and dimercaptosuccinic-acid (DMSA) at least 4 mo after the infection. Voiding cystourethrography (VCUG) was performed only if ultrasonography findings were abnormal, the uptake deformity was detected in DMSA scan, or the patients experienced recurrent UTIs. The patients were grouped concerning E. coli or non- E. coli and ESBL-PB or non-ESBL-BP growth in the urine cultures. Results There were 277 infants followed up for 28.55 ± 15.24 (6–86) mo. The causative microorganisms were non- E. coli in 73 (26.4%) and ESBL-PB in 58 (20.9%) cases. CRP values, pyuria, and leukocyte-esterase positivity were significantly higher in UTIs caused by E. coli compared to non-E. coli bacteria. All clinical and laboratory findings were similar between the ESBL-PB and non-ESBL groups, but abnormal ultrasonography findings were more common in non- E. coli group. Conclusion E. coli causes more severe inflammation, but non- E. coli infections are more frequently associated with ultrasound abnormalities. However, ESBL production did not affect either laboratory or radiological findings in the present cohort.