title: Extended-spectrum β-lactamase-producing Gram-negative pathogens in community-acquired urinary tract infections: an increasing challenge for antimicrobial therapy.
abstract: BACKGROUND
  Extended-spectrum β-lactamases (ESBLs) are an increasing challenge in the treatment of urinary tract infections (UTIs), and also in the community. We aimed to investigate the characteristics of patients with UTIs due to ESBL-producing Escherichia coli and to assess the risk factors for ESBLs in community-acquired isolates.
  
  
  METHODS
  We performed a retrospective study from January 1, 2007 to December 31, 2009 at a tertiary care teaching hospital in Switzerland, comparing patients with community-acquired versus healthcare-associated UTIs due to ESBL-producing E. coli. Additionally, we investigated the antimicrobial susceptibility of these isolates.
  
  
  RESULTS
  A total of 123 patients were studied, of whom 79 (64%) had community-acquired and 44 (36%) had healthcare-associated UTIs. Community-acquired isolates were associated with acute uncomplicated UTIs (odds ratio [OR] 6.62, 95% confidence interval [CI] 1.83-36.5, P < 0.001). Risk factors were recurrent UTI (OR 3.04, 95% CI 1.14-9.14, P = 0.022) and female sex (OR 2.46, 95% CI 1.01-6.08). Community-acquired ESBL-producing E. coli urinary isolates showed high resistance rates to most of the currently used oral antimicrobial agents, including β-lactam antibiotics (amoxicillin-clavulanic acid, 69.6% resistance), quinolones (ciprofloxacin, 84.8% resistance; norfloxacin, 83.9% resistance), and trimethoprim-sulfamethoxazole (75.9% resistance), except for nitrofurantoin (15% resistance) and fosfomycin (0% resistance).
  
  
  CONCLUSIONS
  UTI due to ESBL-producing E. coli are emerging, and also in a country with low antibiotic use. Because of increasing antibiotic resistance rates of E. coli to current standard therapy and because of the resistance patterns of ESBL-producing E. coli, guidelines for the management of UTIs must be revised. Fosfomycin or nitrofurantoin are recommended for the first-line empirical oral treatment of community-acquired uncomplicated UTIs.
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Raemistrasse 100, 8091 Zurich, Switzerland. silvanmeier86@yahoo.ch
authors.forename: S
authors.initials: S
authors.lastname: Meier
authors.forename: R
authors.initials: R
authors.lastname: Weber
authors.forename: R
authors.initials: R
authors.lastname: Zbinden
authors.forename: C
authors.initials: C
authors.lastname: Ruef
authors.forename: B
authors.initials: B
authors.lastname: Hasse
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000453:epidemiology / Q000652:urine; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000201:enzymology* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology* / Q000652:urine; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology; D016896:Treatment Outcome; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology* / Q000652:urine; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000652:urine*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases