Program Schedule

Using an Algorithm to Decrease Fluoroquinolone Use and Effects on Escherichia coli Resistance

Session: Poster Abstract Session: Antibiotic Stewardship
Thursday, October 9, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
  • Seymour_231_IDWeekPoster.pdf (625.3 kB)
  • Background:

    Between 1999 and 2005, fluoroquinolone resistance among urinary Escherichia coli (E. coli) isolates increased markedly at our institution following implementation of an algorithm recommending fluoroquinolones as first line therapy for uncomplicated cystitis (UTI).  In 2007, the algorithm was revised to direct providers to use nitrofurantoin as first line therapy.  The objectives of this study were to evaluate changes in fluoroquinolone and nitrofurantoin prescriptions following this intervention and assess the impact on fluoroquinolone resistance in E. coli.


    This single center, retrospective study included non-pregnant, adult outpatients diagnosed with acute cystitis and prescribed an antibiotic from the emergency department, adult urgent care clinic, or primary care clinic between 2003 and 2012. Changes in antibiotics prescribed for the treatment of UTIs before and after implementation of the algorithm in 2007 and changes in outpatient fluoroquinolone-resistant E. coli isolated from urine were evaluated over time.


    5717 patients and 11,416 E. coli isolates were included. Fluoroquinolones decreased from 65% of prescriptions to 35% while nitrofurantoin use increased from 17% to 29% (P<0.001), with the greatest impact immediately following the intervention. There was no further reduction in fluoroquinolone use in the remaining post-intervention period while nitrofurantoin use had a slight but significant downward trend. (Figure 1) Over the course of the study period E. coli resistance rates to fluoroquinolones increased from 1.5% to 7.6%, however, following the decrease in fluoroquinolone use resistance rates stabilized and decreased slightly each quarter in the post-intervention period. (-0.3%/quarter, P = 0.02) (Figure 2) There was no change in nitrofurantoin resistance, despite increased use.


    The halt and decline of a growing population of fluoroquinolone-resistant E. coli found in the community followed a marked reduction in fluoroquinolone use for UTI management. Despite increased nitrofurantoin use, there was no increase in nitrofurantoin-resistant E. coli. These findings suggest that antimicrobial stewardship interventions can impact the emergence of antimicrobial resistance.

    Rebecca Seymour, PharmD1, Bryan Knepper, MPH, MSc2, Kati Shihadeh, PharmD1, Mike Doody, PharmD1, Michelle Haas, MD3 and Timothy Jenkins, MD3, (1)Acute Care Pharmacy, Denver Health Medical Center, Denver, CO, (2)Patient Safety and Quality, Denver Health Medical Center, Denver, CO, (3)Medicine/Infectious Diseases, University of Colorado-Denver Health Sciences Center, Denver, CO


    R. Seymour, None

    B. Knepper, None

    K. Shihadeh, None

    M. Doody, None

    M. Haas, None

    T. Jenkins, None

    Findings in the abstracts are embargoed until 12:01 a.m. EDT, Oct. 8th with the exception of research findings presented at the IDWeek press conferences.

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