Application of Fluoroquinolone Resistance Score in Management of Complicated Urinary Tract Infections.

ABSTRACT

The fluoroquinolone resistance score (FQRS) predicts the probability of fluoroquinolone resistance with good discrimination. The score has been derived from patients with bloodstream infections caused by Gram-negative bacteria and is based on fluoroquinolone use within the past 6 months, among other clinical and health care exposure criteria. This study aims to examine the utility of the FQRS in patients with complicated urinary tract infections (cUTI) and determine whether extension of prior fluoroquinolone use to 12 months improves model discrimination. Adults with cUTI at Palmetto Health in central South Carolina, USA, from 1 April 2015 through 31 July 2015 were prospectively identified. Multivariate logistic regression was used to examine the association between prior fluoroquinolone use and resistance. Among 238 patients, 54 (23%) had cUTI due to fluoroquinolone-resistant bacteria. Overall, the median age was 66 years, 162 (68%) patients were women, and 137 (58%) patients had cUTI due to Escherichia coli Prior exposure to fluoroquinolones within 3 months (adjusted odds ratio [aOR], 23.4; 95% confidence interval [CI], 8.2 to 76.8; P < 0.001) and within 3 to 12 months (aOR, 13.2; 95% CI, 3.1 to 68.4; P < 0.001) was independently associated with fluoroquinolone resistance compared to no prior use. The area under the receiver operating characteristic curve for the FQRS increased from 0.73 to 0.80 when prior fluoroquinolone use was extended from 6 to 12 months. FQRSs of ≥2 and ≥3 had negative predictive values of 91% and 90%, respectively. The modified FQRS stratifies patients with cUTI on the basis of the predicted probability of fluoroquinolone resistance with very good discrimination. Application of the modified FQRS may improve antimicrobial utilization in patients with acute pyelonephritis.