In this retrospective, case-control study investigators will include all infants (0-1 year) with UTIs who were treated at Hamad General Hospital, pediatric division- PEC Doha, Qatar, using the electronic medical records from 1st January 2015 till January 1st, 2022, diagnosed by a positive urine culture. Investigators will look for the clinical manifestations, radiological and laboratory findings, renal scarring, ESBL-organisms, prevalence, median age, gender, and ethnic background. Participants are divided into two groups: early infancy and late infancy, ESBL UTIs and non-ESBL UTIs, and upper UTIs and lower UTIs. Finally, UTIs ESBL with COVID-19 and without COVID\_19.
