Best oral empirical treatment for pyelonephritis in children: Do we need to differentiate between age and gender?

BACKGROUND: Pyelonephritis is a common infection in childhood and may cause renal scarring. The aim was to determine an effective oral antibiotic treatment of first time pyelonephritis in children.

METHODS: The study is a retrospective analysis of positive urine cultures collected at a Danish paediatric department from 2010-2013. Urine samples from 378 children aged 0-15.9 years, without renal anomalies and treated for first time pyelonephritis, were included. The urine pathogens and antimicrobial susceptibilities were analysed.

RESULTS: The most common aetiologic agents found were Escherichia coli (85%), Klebsiella species and other Enterobacteriaecea (9.7%) and Enterococcus species (5.3%). Escherichia coli was significantly more common in girls than in boys (90% vs 74%, p < 0.001) and in children older than 6 months (89% vs 77%, p < 0.001). Children younger than 6 months had a higher prevalence of other Gram-negative rods (16% vs 7%, p < 0.001). These differences may be due to boys representing 63% of patients in the youngest age group compared to 16% of older children (p < 0.001). For all urine isolates, piv-mecillinam and amoxicillin-clavulanate had the lowest resistance rates of 6.9% and 7.2%, respectively, and 6% for both antimicrobials in patients older than 6 months. Uropathogens from boys above 6 months of age were more resistant to piv-mecillinam compared to girls (25% vs 2.4%, p < 0.001).

CONCLUSION: This study recommends piv-mecillinam or amoxicillin-clavulanate as empirical treatment of first time pyelonephritis in Danish children from 6 months of age. Age and gender of patients should be taken into consideration when initiating empirical treatment.