Preferential Use of Nitrofurantoin Over Fluoroquinolones for Acute Uncomplicated Cystitis and Outpatient Escherichia coli Resistance in an Integrated Healthcare System.

OBJECTIVES To evaluate changes in outpatient fluoroquinolone (FQ) and nitrofurantoin (NFT) use and resistance among E. coli isolates after a change in institutional guidance to use NFT over FQs for acute uncomplicated cystitis. DESIGN Retrospective preintervention-postintervention study. SETTING Urban, integrated healthcare system. PATIENTS Adult outpatients treated for acute cystitis. METHODS We compared 2 time periods: January 2003-June 2007 when FQs were recommended as first-line therapy, and July 2007-December 2012, when NFT was recommended. The main outcomes were changes in FQ and NFT use and FQ- and NFT-resistant E. coli by time-series analysis. RESULTS Overall, 5,714 adults treated for acute cystitis and 11,367 outpatient E. coli isolates were included in the analysis. After the change in prescribing guidance, there was an immediate 26% (95% CI, 20%-32%) decrease in FQ use (P<.001), and a nonsignificant 6% (95% CI, -2% to 15%) increase in NFT use (P=.12); these changes were sustained over the postintervention period. Oral cephalosporin use also increased during the postintervention period. There was a significant decrease in FQ-resistant E. coli of -0.4% per quarter (95% CI, -0.6% to -0.1%; P=.004) between the pre- and postintervention periods; however, a change in the trend of NFT-resistant E. coli was not observed. CONCLUSIONS In an integrated healthcare system, a change in institutional guidance for acute uncomplicated cystitis was associated with a reduction in FQ use, which may have contributed to a stabilization in FQ-resistant E. coli. Increased nitrofurantoin use was not associated with a change in NFT resistance. Infect Control Hosp Epidemiol 2017;38:461-468.