Emergence of ciprofloxacin-gentamicin resistant Escherichia coli: implications for the empirical management of urinary tract infections

Abstract number: O92

Plamondon M., Pépin J., Lacroix C., Deslandes S., Alarie I., Frost É.

Objectives: An increased incidence of urinary tract infections (UTI) caused by ciprofloxacin-gentamicin resistant E. coli (CiGREC) has been observed in our hospital, a tertiary care centre in Canada. Thus, we aimed to determine the risk factors associated with CiGREC UTI and its outcomes, in order to improve the empirical management of patients with UTI pending results of in vitro susceptibility.

Methods: A case control study was conducted between 2000 and 2007. Eighty-four cases and 168 randomly selected controls were identified using laboratory records of patients with >108 CFU of E. coli in a urinary specimen. Cases had E. coli with MIC to ciprofloxacin >2ug/L and MIC to gentamicin >8ug/L (CiGREC), and controls had E. coli with any other susceptibility pattern to ciprofloxacin and gentamicin. Clinical and laboratory data were collected. Univariate and multivariate analyses were used for case-control comparisons.

Results: Prevalence of CiGREC increased four-fold during the study period, from 0.5% to 2.1%. Strains resistant to both ciprofloxacin and gentamicin were more likely than susceptible strains to harbour concomitant resistance to TMP-SMX (62% vs 11%), ampicillin (90% vs 26%) and tobramycin (47% vs 0.4%) (all with p < 0.001), but conserved susceptibility to carbapenems. Risk factors associated with urinary tract infection with the resistant strain were: advanced age, male sex, underlying urologic abnormality, presence of comorbidities with a Charlson score >4, previous use of quinolones in the last month or year and hospital or healthcare acquisition (see table 1). Cases were also more likely to receive inactive antibiotics during the first 48h of treatment (70% vs 28%, p < 0.001) and even after the documentation of the resistance (37% vs 2%, p < 0.001). They also experienced more frequent relapses (28% vs 15%, p = 0.03) and a higher mortality than controls (6% vs 0%, p = 0.04).

Conclusion: The incidence of CiGREC as a cause of urinary tract infection is increasing in our hospital and impacts on the outcomes of our patients. Ciprofloxacin and gentamicin should no longer be used as empirical treatment of UTI among patients who have received quinolones in the previous year.

Table 1. Risk factors associated with urinary infection with a ciprofloxacin–gentamicin resistant strain of Escherichia coli

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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