Urinary tract infections due to extended-spectrum beta-lactamase-producing Gram-negative bacteria: Identification of risk factors and outcome predictors in an Australian tertiary referral hospital

Michael Osthoff, Sarah L. McGuinness, Aaron Z. Wagen, Damon P. Eisen

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Objectives: Extended-spectrum beta-lactamase-expressing Gram-negative bacilli (ESBL-GNB) now commonly cause community-acquired infections, including urinary tract infections (UTI), and represent a challenge for practitioners in choosing empirical antibiotics. The aim of this study was to describe the epidemiology and clinical characteristics of UTIs/bacteriuria due to ESBL-GNB in Australia. Methods: At a single-site tertiary referral hospital, 100 cases with UTIs/bacteriuria due to ESBL-GNB were matched to 100 cases where UTIs/bacteriuria were caused by organisms matching the ESBL bacterial species that had routine susceptibility to antibiotics. Potential risk factors for ESBL-GNB UTI/bacteriuria and differences in clinical outcomes were identified. Results: Length of admission prior to positive sample (odds ratio (OR) 1.3, p= 0.03, per week), exposure to antibiotics (OR 5.7, p<. 0.001), return from overseas travel (OR 6.5, p= 0.002), and nursing home residency (OR 4.2, p= 0.03) were identified as risk factors associated with ESBL-GNB UTI/bacteriuria in the multivariate analysis. In addition, ESBL-GNB-infected cases subsequently had a longer inpatient stay (median 6 vs. 2 days, p= 0.002) and were admitted to the intensive care unit more frequently (28/100 vs. 8/100, p<. 0.001). Conclusions: Our results emphasize the need for culture of a mid-stream urine specimen prior to commencing antibacterials, especially in patients with the risk factors identified herein associated with ESBL-GNB UTI/bacteriuria.

Original languageEnglish
Pages (from-to)79-83
Number of pages5
JournalInternational Journal of Infectious Diseases
Publication statusPublished - 1 May 2015
Externally publishedYes


  • Antibiotic resistance
  • ESBL
  • Gram-negative bacteria
  • Urinary tract infection

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