Urinary tract infection (UTI) is a common bacterial infectious disease in childhood. Especially UTI in infant and young children is associated with urinary tract anomalies such as hydronephrosis, vesicoureteral reflux. The aim of this study was to compare the clinical and laboratory characteristics, and uroradiologic findings of UTI caused by pathogens other than E. coli with UTI caused by E. coli in infant and young children.

We retrospectively reviewed medical records of 170 infants and children, who had been admitted for UTI to Il Sin Christian Hospital from January 2003 to December 2005. All patients were divided into two groups; E. coli and non- E. coli UTI, and they were compared for demographic data, clinical data (degree and duration of fever, time to defervescence, and length of hospital stay), underlying urinary tract anomalies (by history and ultrasonography), recurrent infection (by history and past medical records), and laboratory data [urinalysis, white blood cells (WBC) count in peripheral blood, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum creatinine level].

Of the 170 UTI patients, the number of non- E. coli UTI was 114 (67.1%) and E. coli UTI was 56 (32.9%). As compared to E. coli group, non- E. coli group was younger in age (0.52±0.59 years vs 0.84±1.39years, P <0.05), had higher rates of urinary tract anomalies [n=46 (82.1%) vs n=53 (46.5%), P <0.001], higher recurrence rate, shorter time to defervescence, less peripheral blood WBC count, lower level of CRP, lower level of ESR.

The characteristics of non- E. coli UTI compared to E. coli UTI was younger age, milder clinical symptoms and signs, higher rates of urinary tract anomalies and higher recurrence rate.