Is a repeat urine culture useful during antibiotic therapy for febrile urinary tract infection?

To evaluate the cost-effectiveness of a repeat urine culture after a few days of antibiotic therapy in childhood urinary tract infection (UTI) in southern Thailand.

A retrospective review of the medical record of children diagnosed with UTI aged less than 15 years in Songklanagarind Hospital from January 1995 to December 2004 was performed. Patient demographics were collected. The results of repeat urine culture after starting antibiotic were evaluated. The risk factors that indicated positive repeat urine culture were determined.

Four hundred and forty-nine patients (245 boys and 204 girls) with 533 UTI episodes were analyzed, of which 49 (9.2%) had a repeat urine culture with significant growth. Multivariate analysis showed that age less than 1 year, aetiological agents Enterococci spp., fever of more than 72 h, inappropriate antibiotics and kidney, ureter and bladder anomalies were the most significant risk factors for a positive repeat culture, while sex, vesicoureteral reflux and recurrent UTI episodes were not significant risk factors. If the treatment protocol during the study period had indicated that children with at least one of the above risk factors should receive a repeat urine culture, then only 356 cases (66.8% +/- 2.0%) would have received a repeat test and $US 655 would have been saved, while five positive repeat urine cultures would have been missed.

The present study in a group of Thai children indicates that a repeat urine culture during antibiotic therapy should still be recommended.