Five-Year Antimicrobial Resistance Patterns of Urinary Escherichia coli at an Australian Tertiary Hospital: Time Series Analyses of Prevalence Data

PLoS One. 2016 Oct 6;11(10):e0164306. doi: 10.1371/journal.pone.0164306. eCollection 2016.

Abstract

This study describes the antimicrobial resistance temporal trends and seasonal variation of Escherichia coli (E. coli) urinary tract infections (UTIs) over five years, from 2009 to 2013, and compares prevalence of resistance in hospital- and community-acquired E. coli UTI. A cross sectional study of E. coli UTIs from patients attending a tertiary referral hospital in Canberra, Australia was undertaken. Time series analysis was performed to illustrate resistance trends. Only the first positive E. coli UTI per patient per year was included in the analysis. A total of 15,022 positive cultures from 8724 patients were identified. Results are based on 5333 first E. coli UTIs, from 4732 patients, of which 84.2% were community-acquired. Five-year hospital and community resistance rates were highest for ampicillin (41.9%) and trimethoprim (20.7%). Resistance was lowest for meropenem (0.0%), nitrofurantoin (2.7%), piperacillin-tazobactam (2.9%) and ciprofloxacin (6.5%). Resistance to amoxycillin-clavulanate, cefazolin, gentamicin and piperacillin-tazobactam were significantly higher in hospital- compared to community-acquired UTIs (9.3% versus 6.2%; 15.4% versus 9.7%; 5.2% versus 3.7% and 5.2% versus 2.5%, respectively). Trend analysis showed significant increases in resistance over five years for amoxycillin-clavulanate, trimethoprim, ciprofloxacin, nitrofurantoin, trimethoprim-sulphamethoxazole, cefazolin, ceftriaxone and gentamicin (P<0.05, for all) with seasonal pattern observed for trimethoprim resistance (augmented Dickey-Fuller statistic = 4.136; P = 0.006). An association between ciprofloxacin resistance, cefazolin resistance and ceftriaxone resistance with older age was noted. Given the relatively high resistance rates for ampicillin and trimethoprim, these antimicrobials should be reconsidered for empirical treatment of UTIs in this patient population. Our findings have important implications for UTI treatment based on setting of acquisition.

MeSH terms

  • Aged
  • Ampicillin / pharmacology
  • Ampicillin / therapeutic use
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / therapeutic use
  • Australia / epidemiology
  • Cross-Sectional Studies
  • Drug Resistance, Bacterial / drug effects*
  • Escherichia coli / drug effects*
  • Escherichia coli / isolation & purification
  • Escherichia coli Infections / drug therapy
  • Escherichia coli Infections / epidemiology*
  • Female
  • Humans
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Prevalence
  • Seasons
  • Tertiary Care Centers
  • Trimethoprim / pharmacology
  • Trimethoprim / therapeutic use
  • Urinary Tract Infections / drug therapy
  • Urinary Tract Infections / epidemiology*
  • beta-Lactamases / metabolism

Substances

  • Anti-Bacterial Agents
  • Ampicillin
  • Trimethoprim
  • beta-Lactamases

Grants and funding

This study was carried out as part of a doctoral research program. OF is supported by an Australian Catholic University Postgraduate Award. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.