Different classification systems of UTI exist. Most widely used are those developed by the Centers for Disease Control and Prevention (CDC) [6], Infectious Diseases Society of America (IDSA) [7], European Society of Clinical Microbiology and Infectious Diseases (ESCMID) [8] as well as the U.S. Food and Drug Administration (FDA) [9, 10]. Current UTI guidelines frequently use the concept of uncomplicated and complicated UTI with a number of modifications (Figure 1). In 2011 the EAU/EAU Section of Infections in Urology proposed the ORENUC classification system based on the clinical presentation of the UTI, categorisation of risk factors and availability of appropriate antimicrobial therapy [11]. Figure 1-Concept of uncomplicated and complicated UTI The following classification of UTIs is adopted in the EAU Urological Infections Guidelines: Classification of UTI Uncomplicated UTIs Acute, sporadic or recurrent lower (uncomplicated cystitis) and/or upper (uncomplicated pyelonephritis) UTI, limited to non-pregnant, premenopausal women with no known anatomical and functional abnormalities within the urinary tract or comorbidities. Complicated UTIs All UTIs which are not defined as uncomplicated. Meaning in a narrower sense UTIs in a patient with an increased chance of a complicated course: i.e. all men, pregnant women, patients with anatomical or functional abnormalities of the urinary tract, indwelling urinary catheters, renal diseases, and/or with other concomitant immunocompromising diseases for example, diabetes. Recurrent UTIs Recurrences of uncomplicated and/or complicated UTIs, with a frequency of at least three UTIs/year or two UTIs in the last six months. Catheter-associated UTIs Catheter-associated urinary tract infection (CA-UTI) refers to UTIs occurring in a person whose urinary tract is currently catheterised or has been catheterised within the past 48 hours. Urosepsis A systemic, deleterious host response to infection originating from the urinary tract and/or male genital organs. Urosepsis is accompanied by signs of systemic inflammation, presence of symptoms of organ dysfunction and persistent hypotension associated with tissue anoxia. 3.2 Antimicrobial stewardship Antimicrobial stewardship programmes aim to optimise the outcome of prevention and treatment of infection whilst curbing overuse and misuse of antimicrobial agents [12-16]. Measures of success include regulating antimicrobial prescribing, and reduction in both the rate of healthcare associated infections such as Clostridium difficile and the emergence of resistant organisms [16]. In urology, antimicrobial stewardship programmes should include a series of measures to ensure rational, evidence based use of antimicrobials in the prevention and treatment of infections of the urinary tract and male accessory glands, as well as non-antimicrobial strategies. Programmes require a stewardship team approach comprising urologists, infectious diseases Cystitis Pyelonephritis Recurrent UTI Catheter-associated UTI Urosepsis Complicated UTI Uncomplicated UTI U...