Background: Urinary tract infections (UTI) belong to the most frequent bacterial infections in outpatients. Increasing antibiotic resistance rates and a new appreciation of the epidemiological side effects of antibiotics ("collateral damage") have warranted an update of the guidelines on uncomplicated UTI as an S3 clinical guideline.
Methods: The guideline was developed by the Deutsche Gesellschaft für Urologie (DGU) in collaboration with the Deutsche Gesellschaft für Allgemein- und Familienmedizin (DEGAM), Deutsche Gesellschaft für Gynäkologie und Geburtshilfe (DGGG), Deutsche Gesellschaft für Hygiene und Mikrobiologie (DGHM), Deutsche Gesellschaft für Infektiologie (DGI), Deutsche Gesellschaft für Nephrologie (DGfN), Paul-Ehrlich-Gesellschaft für Chemotherapie (PEG) and a patient representative. The systematic review of the literature on the topics of the guideline was performed for the time period of 1 January 1998 to 30 April 2008 in the databases of the Cochrane Library and MEDLINE. International guidelines of the years 1999-2007 were included.
Results: Uncomplicated UTI comprise uncomplicated cystitis and uncomplicated pyelonephritis. The leading uropathogen is Escherichia coli. The choice of the antibiotic substance follows the five primary aspects: (1) individual patient risk and antibiotic pretreatment; (2) bacterial spectrum and antibiotic susceptibility; (3) effectivity of the antimicrobial substance demonstrated in clinical studies; (4) epidemiological effects ("collateral damage"); and (5) adverse effects. If antibiotics such as trimethoprim/sulfamethoxazole or fluoroquinolones have previously been given, the risk for pathogens to become resistant against these substances is increased. Because of increasing resistance rates of E. coli against trimethoprim/sulfamethoxazole also in uncomplicated UTI, trimethoprim alone or in combination with sulfamethoxazole is no longer regarded as the first-line agent in the empiric treatment of uncomplicated cystitis, unless the regional resistance rate is below 20%. The antibiotic resistance rates of fluoroquinolones in uncomplicated UTI are still below 10% in Germany, but there is a significant emergence of resistance compared to earlier years. Moreover, fluoroquinolones and group 3 cephalosporins exhibit negative epidemiological effects resulting in selection of multi-resistant pathogens. Because these antibiotic classes are needed in therapy of life-threatening infections, such effects should be taken seriously. For substances like fosfomycin, nitrofurantoin or mecillinam"collateral damage" has not been documented or only to a lesser degree. Therefore, for empiric therapy of frequent uncomplicated cystitis fosfomycin-trometamol, nitrofurantoin or pivmecillinam (not listed in Germany) are recommended as first-line antibiotics. For oral first-line treatment of uncomplicated pyelonephritis, fluoroquinolones are still recommended in sufficiently high dosage due to the resistance rates of E. coli still being below 10% and the superior effectivity compared to other antibiotics. Asymptomatic bacteriuria (ASB) should only be treated in exceptional cases such as pregnant women or prior to expected mucocutaneous traumatising interventions of the urinary tract.
Conclusion: The S3 guideline on uncomplicated urinary tract infections is a comprehensive set of evidence- and consensus-based recommendations dealing with epidemiology, diagnosis, therapy and management of uncomplicated bacterial UTI of adult outpatients. A broad implementation in all disciplines taking care of patients with UTI is necessary in order to ensure a prudent antibiotic policy in these frequent infections and thus improve patient care.