 This study was created by the GPIPACTIV network with 24 pediatric centers pediatric and emergency department working with their microbiology departments throughout France. Between March 2014 and March 2017, they enrolled all children treated for UTI by E-ESBL in this prospective observational study. These hospitals were located in 7 regions Ile de France, Nord-Pas-de-Calais-Picardie, Provence-Alpes-Côte dAzur, Seine-Maritime, Rhône and Loire-Atlantique. For this hospital-based active surveillance, a clinical investigator in each participating ward completed a standardized data form sent by electronic or postal mail to the investigating center. All data were validated by a scientific committee. 