Is combination antimicrobial therapy required for urinary tract infection in children?

This retrospective study examined the characteristics of 338 pediatric patients presenting with a first episode of symptomatic urinary tract infection at Taichung Veterans General Hospital from November 1996 to December 2001. Escherichia coli was the most common pathogen (72.5%), followed by Proteus mirabilis (8.3%), Enterococcus (5.6%), and Klebsiella pneumoniae (4.7%). They were more susceptible to first-generation cephalosporin in comparison with other first-line antimicrobial agents such as trimethoprim/sulfamethoxazole, ampicillin, and gentamicin. Two hundred and eighty-seven (84.9%) of the 338 patients were divided into 3 groups according to the type of antibiotic treatment received, and the susceptibility rate and the averaged day of defervescence after effective antibiotic therapy were compared among the groups. Group 1 consisted of those patients treated with cefazolin or cephalexin alone (95%, 2.1 days); Group 2, cefazolin plus gentamicin (88.9%, 2.8 days); and Group 3, ampicillin plus gentamicin (76.1%, 2.3 days). A total of 38 (13.2%) cases from the 3 antibiotic groups did not respond to empiric antibiotics. For non-susceptible infections, when the antibiotic regimen was switched from cefazolin plus gentamicin to ampicillin alone, only 4 (20%) strains became susceptible, compared with 10 strains (62.5%) becoming susceptible after switching from ampicillin plus gentamicin to cefazolin alone (p < 0.01). The results indicated that first-generation cephalosporin alone is an appropriate treatment for pediatric cases of community-acquired urinary tract infection and suggest that antimicrobial combinations should be reserved for serious or critical cases.