Background：Recently our institution noted a marked increase in the number of ExtendedSpectrum β-Lactamase(ESBL)-producing Escherichia coli isolated from children with urinary tract infections (UTI). The purpose of this study was to investigate frequency, risk factors and outcomes for pediatric UTI due to ESBL-producing E. coli.

Methods：We analyzed 27 children with UTI due to ESBL-producing E. coli (cases) and 27 children with UTI due to non-ESBL-producing E. coli (controls) in Ewha Womans University Hospital from July to December 2001.

Results：Of the total 434 E. coli isolates from urine, 32 (7.4%) produced ESBL and the prevalence of UTI due to ESBL-producing E. coli was higher in children (15.2%) than in adults (2.0%). Case patients had higher resistances to ampicillin/sulbactam, aztreonam, cefazolin, ceftriaxone, gentamicin, tobramycin, TMP-SXT and piperacillin/tazobactam than controls. No significant differences were noted in resistance to amikacin, ampicillin, cefoxitin, ciprofloxacin and imipenem (P>0.05). Case patients were younger and more frequently male than control patients. No significant differences were noted in prior UTI, prior antibiotic use, genitourinary abnormality, vesicoureteral reflux, urinary catheter, pyelonephritis or underlying diseases (P>0.05). No significant difference in cure rate was noted between both groups, but case patients had a significantly higher relapse (11/27) than control patients (1/27) (P<0.05).

Conclusions：ESBL-producing E. coli may be a causative agent of UTI in children without any specific risk factors. To eradicate ESBL-producing strains, new guidelines of detection and antibiotic therapy for pediatric UTI may be necessary through more evaluation. (Korean J Clin Microbiol 2003;6(2):132-138)