[Complicated urinary tract infections].

Urinary tract infections (UTIs) are among the most common bacterial infections in Germany, both in outpatient and inpatient settings. The clinical spectrum is heterogeneous and ranges from benign, often self-limiting, uncomplicated infections to complicated urinary tract infections (cUTIs) with life-threatening courses. Complicated urinary tract infections have a higher risk of chronicity, recurrence and/or progression than uncomplicated infections and may be associated with severe disease progression. Stratification of patients with urinary tract infections is, therefore, of utmost importance. Host factors rather than pathogen attributes determine the pathophysiology and therapy of complicated urinary tract infections and pyelonephritis. Complicated UTIs and pyelonephritis are also associated with high rates of antimicrobial resistance in the causative pathogens, so they should be given particular emphasis.