Nickan Research Institute Journal of Renal Injury Prevention 2345-2781 11 1 2022 03 01 Clinical and laboratory differences between extended-spectrum β-lactamase-positive and extended-spectrum β-lactamase-negative bacteria in febrile urinary tract infection in pediatrics e2 e2 10.34172/jrip.2022.02 EN Manijeh Kahbazi https://orcid.org/0000-0002-7824-8132 Parsa Yousefichaijan https://orcid.org/0000-0003-1196-1264 Danial Habibi https://orcid.org/0000-0003-4080-1809 Somaie Nejabat https://orcid.org/0000-0003-1513-0222 Amirreza Najmi https://orcid.org/0000-0001-8487-8125 Fateme Karimi https://orcid.org/0000-0002-9493-4204 Journal Article 10.34172/jrip.2022.02 2020 10 04 2021 08 02 Introduction: The prevalence of urinary tract infections (UTIs) due to extended-spectrum beta-lactamase (ESBL)-producing bacteria is rising, which needs more potent antibiotics, such as carbapenems. Objectives: To evaluate the clinical and laboratory differences between ESBL-positive and ESBL-negative bacteria in febrile UTI in children between one month to seven years to indicate prognostic parameters for ESBL+ UTI and to suggest appropriate antibiotic treatment. Patients and Methods: This cross-sectional study investigated 282 patients diagnosed with the first febrile UTI. The participants were assigned to ESBL-positive and ESBL-negative UTI groups. The groups were compared based on their clinical and laboratory characteristics and outcomes; the infant group was assessed separately (with the onset age of <3 months). Results: The ESBL UTI was detected in 10.2% of the cases with a history of more frequent hospitalization (P=0.002), longer hospitalization (P=0.04), higher recurrence rate (P=0.003), and more red blood cell count in urine analysis findings (P=0.02). In the antimicrobial susceptibility assay, the ESBL-positive UTI group indicated resistance to third-generation cephalosporins; nevertheless, 93.1% of the cases responded clinically. The infant group showed 13% of the patients with ESBL-positive UTI that was correlated with a history of longer preonset hospital stay (P=0.001), elevated C-reactive protein (CRP) concentration (P=0.002), and elevated recurrence rate (P=0.03), compared to the older group. Conclusion: The ESBL UTI should be further considered due to the resulted recurrence rate. The antimicrobial sensitivity assay indicated resistance to third-generation cephalosporins; however, these drugs are applied as the first choice due to the high response rate. Aminoglycosides are applicable as second choice drugs prior to initiating the use of carbapenems, if third-generation cephalosporins did not indicate bactericidal impacts on ESBL UTI.