Nursing homes as a reservoir of extended-spectrum beta-lactamase (ESBL)-producing ciprofloxacin-resistant Escherichia coli

J Antimicrob Chemother. 2009 Sep;64(3):635-41. doi: 10.1093/jac/dkp220. Epub 2009 Jun 23.


Background: To assess the prevalence and risk factors for faecal carriage of fluoroquinolone-resistant, extended-spectrum beta-lactamase (ESBL)-producing, Escherichia coli (MDR E. coli) among residents in nursing homes in Northern Ireland.

Methods: Between January 2004 and May 2006, retrospective histories of hospital admissions, antimicrobial treatment and co-morbidities were collected. Faecal samples were cultured for MDR E. coli. These isolates and their ESBL genes were typed by a reference laboratory.

Results: Of the 294 patients included in the study, faecal samples from 119 (40.5%) grew MDR E. coli. The proportion of carriers in the different homes ranged from 0% to 75%. Epidemic strain A belonging to the ST131, O25:H4 lineage with the CTX-M-15 enzyme accounted for 58 (49%) of all isolates; its proportion varied from 0% to 100% among homes. Fifty-one percent of carriers had no history of recent hospital admission and only 13.5% had a known history of ESBL E. coli colonization or infection. In a multivariate logistic regression model, days of fluoroquinolone use [odds ratio (OR) = 1.33, 95% confidence interval (CI) 1.04-1.69, P = 0.02] and a history of urinary tract infection (OR = 2.56, 95% CI 1.37-4.78, P = 0.003) were the only variables independently associated with the risk of carrying MDR E. coli.

Conclusions: The high level of faecal carriage of MDR E. coli in nursing home residents demonstrates their importance as a reservoir population. Public health measures to combat spread of these organisms should address the needs of this group.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / pharmacology*
  • Carrier State / epidemiology*
  • Carrier State / microbiology
  • Ciprofloxacin / pharmacology*
  • Drug Resistance, Multiple, Bacterial*
  • Escherichia coli / drug effects*
  • Escherichia coli / isolation & purification
  • Escherichia coli Infections / epidemiology*
  • Escherichia coli Infections / microbiology
  • Feces / microbiology
  • Female
  • Humans
  • Male
  • Northern Ireland / epidemiology
  • Nursing Homes
  • Prevalence
  • beta-Lactamases / biosynthesis*
  • beta-Lactams / pharmacology*


  • Anti-Bacterial Agents
  • beta-Lactams
  • Ciprofloxacin
  • beta-Lactamases