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

Abstract

<p>This study describes the antimicrobial resistance temporal trends and seasonal variation of<em> Escherichia coli </em>(<em>E</em>. <em>coli) </em>urinary tract infections (UTIs) over five years, from 2009 to 2013, and compares prevalence of resistance in hospital- and community-acquired <em>E</em>. <em>coli </em>UTI. A cross sectional study of <em>E</em>. <em>coli </em>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 <em>E</em>. <em>coli </em>UTI per patient per year was included in the analysis.</p> <p>A total of 15,022 positive cultures from 8724 patients were identified. Results are based on 5333 first <em>E</em>. <em>coli </em>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</p>