URINARY TRACT INFECTIONS: Edited by Suzanne E. GeerlingsFebrile urinary tract infections pyelonephritis and urosepsisSchneeberger, Carolinea; Holleman, Fritsb; Geerlings, Suzanne E.cAuthor Information aDepartment of Medical Microbiology, University of Amsterdam bDepartment of Internal Medicine cDepartment of Infectious Diseases, Centre for Infection and Immunity Amsterdam, Academic Medical Centre, Amsterdam, the Netherlands Correspondence to Caroline Schneeberger, Department of Medical Microbiology, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, the Netherlands. Tel: +31612388308; e-mail: firstname.lastname@example.org Current Opinion in Infectious Diseases: February 2016 - Volume 29 - Issue 1 - p 80-85 doi: 10.1097/QCO.0000000000000227 Buy Metrics Abstract Purpose of review Complicated infections of the urinary tract (UTI) including pyelonephritis and urosepsis are also called febrile UTI. This review describes insights from the literature on this topic since July 2014. Recent findings Recent studies regarding risk factors and consequences of febrile UTI confirmed existing knowledge. It remains difficult to obtain insight into the epidemiology of febrile UTI because urine and blood cultures are frequently missing. The relationship between host and virulence factors of Escherichia coli was further explored showing that less virulent strains can cause infection in immunocompromised patients. In contrast to obstructive uropathy, diabetes, and being older, neutropenia was not a risk factor for lower UTI or urosepsis. A randomized controlled trial revealed that ceftolozane–tazobactam was marginally superior to levofloxacin as treatment for complicated UTI. Case series supported the notion that xanthogranulomatous and emphysematous pyelonephritis are more common in diabetic patients and that drainage or surgery is often required. Summary Neutropenia was not a risk factor for lower UTI or urosepsis. When local resistance percentages to the frequently prescribed fluoroquinolones are high, the combination of ceftolozane–tazobactam may be an alternative as treatment for complicated UTI. Xanthogranulomatous and emphysematous pyelonephritis need to be considered in diabetic patients presenting with UTI symptoms. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.