Prevalence and risk factor analysis of trimethoprim-sulfamethoxazole and fluoroquinolone-resistant Escherichia coli infection among emergency department patients with pyelonephritis
Talan DA, Krishnadasan A, Abrahamian FM, Stamm WE, Moran GJ, for the EMERGEncy ID NET Study Group
Background. High rates of resistance to trimethoprim-sulfamethoxazole (TMP-SMX) among uropathogenicÂ Escherichia coliÂ are recognized, and concerns exist about emerging fluoroquinolone resistance.
Methods. Adults presenting to 11 US emergency departments with (1) flank pain and/or costovertebral tenderness, (2) temperature >38Â°C, and (3) a presumptive diagnosis of pyelonephritis were enrolled; patients for whom 1 uropathogen grew on culture were analyzed. Epidemiologic and clinical data were collected at the time of care. The prevalence ofÂ E. coliÂ in vitro antibiotic resistance and risk factors associated with TMP-SMXâ€“resistantÂ E. coliÂ infection were determined.
Results. Among 403 women with uncomplicated pyelonephritis caused byÂ E. coli, the mean site rate ofÂ E. coliÂ resistance to TMP-SMX was 24% (range, 13%â€“45%). Mean site rates ofÂ E. coliÂ resistance to ciprofloxacin and levofloxacin were 1% and 3%, respectively. Only TMP-SMX exposure within 2 days before presentation and Hispanic ethnicity A1:G39 associated withÂ E. coliÂ resistance to TMP-SMX (compared with resistance rates of âˆ¼20% among women lacking these risk factors); antibiotic exposure within 3â€“60 days before presentation, health care setting exposure within 30 days before presentation, history of urinary tract infections, and age >55 years were not associated withÂ E. coliÂ resistance to TMP-SMX. Among 207 patients with complicated pyelonephritis, mean site rates ofÂ E. coliresistance to ciprofloxacin and levofloxacin were 5% and 6%, respectively.
Conclusions. These results suggest that the prevalence of TMP-SMXâ€“resistant infection among patients with uncomplicated pyelonephritis is â©¾20% in many areas of the United States, and risk stratification cannot identify patients at low risk of infection. Rates of fluoroquinolone-resistantÂ E. coliÂ infection appear to be low among patients with uncomplicated pyelonephritis but higher among those with complicated infections. Fluoroquinolones should remain to be the preferred empirical treatment for women with uncomplicated pyelonephritis.
Full text available at: Clinical Infectious Diseases