Antimicrobial resistance patterns in urinary E. coli isolates after a change in a single center's guidelines for uncomplicated cystitis in ambulatory settings.

Recommending nitrofurantoin to treat uncomplicated cystitis was associated with increased nitrofurantoin use from 3.53 to 4.01 prescriptions per 1,000 outpatient visits, but nitrofurantoin resistance in E. coli isolates remained stable at 2%. Concomitant levofloxacin resistance was a significant risk for nitrofurantoin resistance in E. coli isolates (odds ratio [OR], 2.72; 95% confidence interval [CI], 1.04-7.17).