Prevalence of Fluoroquinolone- and Ceftriaxone-resistant E. coli among U.S. Emergency Department Patients with Acute Pyelonephritis
To determine the prevalence of and potential risk factors for fluoroquinolone-resistant and ESBL-producing E. coli, we report preliminary results of patients with acute pyelonephritis presenting to a network of U.S. emergency departments (EDs, EMERGEncy ID NET).
This is a prospective observational study of patients ≥18 years old with flank pain and/or costovertebral angle tenderness, ED temperature ≥38įC, and clinically suspected acute pyelonephritis. Historical and examination data were collected during the index visit. Enrolled patients provided a urine specimen and cultures growing E. coli >103 cfu/ml were tested for antimicrobial susceptibility. Some isolates with a ceftriaxone MIC >1 μg/ml were tested for ESBL at site labs, and all will have confirmatory testing at a reference lab. Prevalence of resistance was compared to a similar study conducted in 2000-2004.
We have enrolled 371 subjects since July 2013 from 9 EDs; 62 were excluded because a urine culture was not done or the specimen was contaminated.† Of 309 subjects, median age was 37 years and 86.4% were female. Of the 230 (74.4%) that grew a pathogen, 210 (91.3%) grew E. coli. Among those with E. coli infection, the isolate was fluoroquinolone-resistant in 13.9% and ceftriaxone-resistant in 8.1%. Among those with any or none of antibiotic exposure in the previous 2 months, hospitalization or residence in a long term care facility (LTC) in the previous 90 days, the prevalence of fluoroquinolone resistance was 22.9% and 11.3%, and ceftriaxone resistance was 18.8% and 5.0%, respectively. Among those with ceftriaxone-resistant E. coli infection, 47.1% used antimicrobials in the previous 2 months, and 17.6% had been hospitalized or resided in a LTC in the previous 90 days. At site labs, 11/17 ceftriaxone-resistant E. coli isolates were tested for ESBL and all were positive. In 2000-2004, among a similar ED population, the prevalence of E. coli fluoroquinolone resistance was 4.0% and no ESBL infections were found.
Based on our preliminary data, the prevalence of E. coli fluoroquinolone resistance has increased, and ceftriaxone resistance, often due to ESBL production, is now being seen in U.S. ED patients, including among those without recent health care setting exposure.
W. Mower, None
F. Abrahamian, None
S. Takhar, None
D. Talan, Centers for Disease Control and Prevention: Grant Investigator, Research grant